THE 
Parallax of a Lyrt and 61 Cygni. 
BY 
ASAPH HALL, 
PROFESSOR OF MATHEMATICS, U. S. NAVY. 
REAR-ADMIRAL JOHN RODGERS, U. S. NAVY, 
SUPERINTENDENT OF NAVAL OBSERVATORY. 
WASHINGTON: 
GOVERNMENT PRINTING OFFICE. 
1 8 8 2. TABLE OF CONTENTS. 
Page. 
Introduction v 
Method of observing Vi 
Corrections for differential refraction vii-vm 
Observations of a Lyrae and companion 9-30 
Observations of 612 Cygni and D. M. + 38°, 4345 31-41 
Probable errors of a single measurement 42 
Reduction for precession, nutation, and aberration 42-43 
Reduction for proper motion 44 
Reduction for temperature 44-46 
Numerical values of the reductions 47-51 
Formulae for equations of condition 51 
Equations of conditions a Lyrae, 111. A 52-53 
Equations of conditions a Lyrae, 111. B 53—54 
Equations of condition 6t3 Cygni 55-56 
Normal equations a Lyrae, 111. A 56 
Normal equations a Lyrae, 111. B 57 
Parallax of a Lyrae 58 
Nqrmal equations and Parallax of 61 Cj’gni 58-59 
Observations of a Lyrae, 1862-1867 61-63 
Coefficient of temperature for the screw of the micrometer 64 INTRODUCTION- 
Tn the year 1862 a series of observations of a Lyras was begun at the Naval 
Observatory by Prof. J. S. Hubbard, for the purpose of determining the annual 
parallax of this star, and also for obtaining new values of the constants of aberration 
and nutation. These observations were determinations of the declination of the star 
with the Prime Vertical Transit Instrument according to the method followed by AV. 
Struve. The work was continued by Professor Hubbard until his death, in 1863; 
and afterward by Professors Newcomb, Harkness, and myself until April, 1867. An 
examination of these observations was made by Professor Cleveland Abbe in the 
latter part of the year 1867, when it became apparent that a negative value of the 
parallax would result, a fact indicating some systematic error in the work. Although 
the parallax of this star has been determined by several astronomers, still, considering 
the above failure, it seemed worth while to make an attempt by the differential method 
while the Naval Observatory remains on its present site. Moreover, the parallaxes of 
the lixed stars being very small quantities, which have a period of a year, during 
which the observer and his instruments undergo great changes of temperature, the 
determination of the parallax of any star by a new observer with a new instrument, 
and under different climatic conditions, is not, I think, a superfluous work. 1 began, 
therefore, a series of observations of a Lyne on May 24, 1880, which was ended on 
duly 2, 1881; observations having been made on 77 nights. As the interesting 
double star, 61 Cygni could also be observed without spending much more time, a 
similar series of observations of tins 'Star was begun on October 24, 1880, and ended 
December 7, 1881. This star was observed on 66 nights. The observations were 
not made on every clear night, my purpose being to obtain only data enough to give 
trustworthy values of the parallax; but even with this limitation these observations 
have taken much more time than I expected. My house is distant about one mile 
from the Observatory, and frequently during the winter and spring months on reaching 
the Observatory I would find the images so bad that no measurements for parallax 
could be made, or the sky would become covered with clouds. During the spring 
months, when the observations came at an inconvenient hour of the night, General 
Hazen, of the Signal Office, very kindly sent me predictions of the weather which 
proved to be remarkably correct. 
I am indebted to Air. G. Anderson for faithful assistance during all this work. 
These observations have been made with the filar micrometer of the 26-inch 
refractor, and an achromatic eye-piece, giving a magnifying power of 383, has been used 
throughout. O11 some of the nights the images would .have borne a higher power, INTRODUCTION. 
but, as the work was differential, the was not changed. Since observations 
of the angle of position made with the circle of our micrometer are less accurate for 
distances that must be used in determinations of parallax, I have observed simply 
the difference of declination of a Lyrce and its companion of the iotli magnitude. In 
the case of 61 Cygni the difference of declination of the smaller of these stars and a 
star of the 9.5 magnitude, about 3'.3 south of the double star, was observed. This 
star is D. M. + 38°, No. 4345. The observations were made in the following manner: 
After the stellar focus of the telescope had been adjusted by examining a close double 
star with a high power, and the parallel of the wires had been carefully determined, 
the telescope was clamped in declination, the driving clock was put in, and the stars 
were placed so that they were equidistant from the center of the field in declination 
and midway in right ascension. Five bisections and readings for the difference of 
declination were made in the first position of the wires, then the wires were reversed 
and five more bisections were made. These ten readings having been made, the 
micrometer was reversed 180°, and a similar set was made in this position of the 
micrometer; the wires at the end of the work being restored to their first position. In 
making these bisections both screws were turned several revolutions after each read 
ing, in order to render the single measurements independent of each other. The side- 
real clock and the thermometer in the dome were read at the beginning and at the end 
of the bisections. After finishing the observation the driving clock was thrown out 
and the parallel of the wires was examined by the star observed for the purpose of 
detecting any erroneous setting of the position circle. This programme was strictly 
followed in all the observations except in the first observation of a Lyrce, on May 24, 
1880, when only four bisections were made in each position of the wires; but as the 
images were unusually good on that day I have considered this as a normal observa- 
tion. In the observations of a Lyrce two kinds of illumination were used, the bright 
wires being denoted by B and the dark wires with a bright field by A. For 612 Cygni 
only the dark wires were used. 
The following are the observations of these stars that I have made during the 
past eighteen months. All the readings of the micrometer are given, only a few 
incomplete observations being omitted, where the work was interrupted by clouds 
and which can give no results. An examination of the observations will show that a 
few cases occur where it is probable that an error of a tenth of a revolution was made 
in reading the head of the micrometer, but I have not ventured to make any change, 
since in most of these cases the images were poor, and the apparently erroneous 
readings are within the limits of possible error. Most of the quantities in the follow- 
ing table will be understood from the headings of the columns, and these need no 
explanation. The differences of declination given in the column AS have been com- 
puted from the quantities of the preceding column by the equation 
iR = 4."9737 
The column Ap contains the corrections for differential refraction. The principal part 
of this correction has been computed from the formula 
* Ap — AS.k (tan z2 cos <f -f- 1) INTRODUCTION. 
where z is the zenith distance, <y the parallactic angle, and the factor k, expressed in 
parts of radius, serves for the mean condition of the thermometer and barometer. 
Generally this quantity is of the form 
k — a /3K yA, 
where the factors that multiply a depend on the thermometer and barometer; and in 
our case these factors differ but little from unity. The first of the following tables 
gives the correction for differential refraction under the assumption 
k — a, 
and the second table gives the factor by which this correction is to be multiplied in 
order to give the correction corresponding to the actual state of the thermometer and 
barometer. 
Table I for dp. 
k — a. 
Hour 
Angle. 
Hour 
Angle. 
a Lyrne. 
612 Cygni. 
h. 
rri. 
h. 
m. 
» 
- 
o 
o 
24 
0 
0.012 
+ 0.056 
o 
20 
23 
40 
0.012 
0.056 
o 
40 
23 
20 
0.012 
0.056 
t 
O 
23 
O 
0.012 
0.056 
I 
20 
22 
40 
0.012 
0.056 
I 
40 
22 
20 
0.012 
0.056 
2 
o 
22 
O 
0.012 
0.056 
2 
20 
21 
40 
0.013 
0.057 
2 
40 
21 
20 
0.013 
0.057 
3 
° 
21 
o 
0.013 
0.058 
3 
20 
20 
40 
0.013 
0.059 
3 
40 
20 
20 
0.013 
0.061 
4 
0 
20 
o 
0.014 
0.063 
4 
20 
19 
40 
0.015 
0.067 
4 
40 
19 
20 
0.016 
0.073 
5 
° 
19 
o 
0.CI8 
0.081 
5 
20 
18 
40 
0.021 
0.093 
5 
40 
iS 
20 
4- 0.025 
+ 0.108 INTRODUCTION. 
Table II for dp. 
Therm. 
Barometer. 
26in.6. 
30in.6. 
° 
o 
1.11 
i.»5 
IO 
1.08 
1.12 
20 
1.06 
1.10 
> 
30 
1.04 
1.07 
40 
1.02 
1. os 
50 
1.00 
1.03 
60 
0.98 
1.01 
70 
0.96 
0.99 
80 
0.94 
0.97 
QO 
0.92 
0-95 
The weights given in the next column depend only on the condition of the 
images, and were estimated at the time of observation. In the column of “Remarks” 
the kind of illumination js distinguished for the observation of « Lyrce, and the notes 
of the observer recorded at the time of the observations are also given. Then are 
given the mean time of the observation, the mean values of the difference of declina- 
tion, the adopted correction for differential refraction, and the probable error of a 
single difference of declination, this value of the error being deduced from the work 
of each night. THE PARALLAX OF a AND 61 CYGNI. 
9 
Observations of a Jjyr<e and Companion. 
Date. 
< lock Time 
and ('orr. 
Hour 
Angle. 
Temp. 
M icr. 
Micr. 
2 A5 
AS 
A p 
Wt. 
Remarks. 
i8&>. 
May 24 
h. m. 
h. 
m. 
73-5 
r. 
59.678 
r. 
68.533 
8.855 
44 04 
" 
4 
111. A. 
.689 
539 
.850 
44 02 
16 42 
22 
6.3 
.688 
59.681 
•551 
68.559 
.863 
.878 
44.08 
44 16 
+ 
0.012 
T — 
AS = 
I2h 26™.5 
44”.122 
68.553 
59.678 
.875 
44M 
Ap = 
+ 
o".OI2 
- 2-8 
•539 
.672 
.867 
44.10 
1*1 = 
± 
o".o5i 
■554 
.661 
•893 
44 23 
73.2 
•555 
.667 
.888 
44.21 
May 25 
16 27 
21 
51 2 
77.0 
59.638 
68.567 
8.929 
44 4i 
+ 
0.012 
2 
111. A. 
.641 
•571 
.930 
44-42 
.638 
•545 
•9°7 
44 3° 
.660 
•543 
.883 
44.18 
— 2 "".9 
59.681 
68.536 
•855 
44.04 
T == 
I2h igm.g 
68.534 
59.668 
.866 
44.10 
AS = 
44”-i99 
•539 
.662 
.877 
44 15 
Ap - 
+ 
o".OI2 
•532 
.625 
•9°7 
44-3° 
r, = 
± 
o".ioo 
•532 
•679 
•853 
44.03 
16 52 
22 
16.2 
76.6 
•54° 
.682 
.858 
44.06 
+ 
0.012 
May 26 
16 16 
21 
40.2 
78.0 
59.664 
68.517 
8.853 
44.03 
+ 
0.012 
2 
111. A. 
•635 
•543 
.908 
44-31 
.660 
•579 
.919 
44-36 
.650 
.540 
.890 
44.22 
— 2".9 
59.676 
68.550 
.874 
44.14 
T = 
,2h 0 
68.512 
59.660 
.852 
44 03 
AS zr 
44".185 
•529 
.641 
.888 
44.21 
Ap = 
+ 
o".OI2 
•54° 
•637 
• 9°3 
44.28 
ri = 
± 
°"-°74 
• 520 
.647 
•873 
44-13 
17 5 
22 
29.2 
76-S 
.528 
•6*14 
.874 
44 14 
+ 
0.012 
May 27 
IS 33 
20 
57 1 
75.0 
59.700 
68.580 
8.880 
44.17 
+ 
O.OI3 
2 
111. B. 
•679 
556 
•877 
44-15 
•633 
•535 
.902 
44.28 
.670 
•579 
.909 
44-31 
59.688 
68.579 
.891 
44.22 
T = 
IIh 2Im.6 
- 3" ° 
68.494 
59.609 
.885 
44-19 
AS = 
44”.242 
•542 
.640 
.902 
44.28 
Ap = 
+ 
o".oi3 
•548 
.660 
.888 
44.21 
r, = 
± 
o".04i 
•552 
.641 
.911 
44-32 
16 5 
21 
29.I 
74-5 
•553 
.648 
•9°5 
44.29 
+ 
0.013 
May 27 
16 29 
21 
53-1 
73.6 
59.670 
68.562 
8.892 
44 23 
+ 
0.012 
2 
111. A. 
.664 
•559 
895 
44 24 
715 
•521 
.806 
43.80 
•654 
•535 
.881 
4417 
— 3“o 
59-637 
68.553 
.916 
44-35 
T = 
I2h I3m.O 
68.543 
59-632 
.911 
44-32 
AS = 
44".168 
•539 
.660 
.879 
44.16 
Ap - 
+ 
o".OI2 
•534 
•639 
• 895 
44 24 
1*1 = 
± 
o".n8 
.561 
.665 
.896 
44 25 
16 52 
22 
l6. I 
73-2 
.509 
.679 
.830 
43.92 
+ 
0.012 
May 31 
IS 23 
20 
57 0 
72.0 
59-65° 
68.556 
8.906 
44-3° 
+ 
0.013 
2 
111. B. 
.671 
•575 
.904 
44 29 
• 
.675 
.550 
•875 
44 M 
.685 
•554 
.869 
44.11 
- 3". 1 
59 623 
68.550 
•927 
44-4° 
T — 
nh 5m.8 
68.552 
59.687 
.865 
44.09 
AS = 
44".212 
•54° 
.669 
.871 
44.12 
Ap = 
+ 
o".oi3 
561 
.666 
•895 
44-24 
1*1 - 
± 
o,f.ogi 
•559 
.630 
.929 
44-41 
16 s 
21 
29.0 
71-5 
•521 
.671 
.850 
44.02 
+ 
O.OI3 10 
THE PARALLAX OF a LYR.E AND 61 CYGNI. 
Observations of a Lyra? and Companion—Continued. 
Date. 
Clock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2AS 
AS 
A p 
Wt. 
Remarks. 
1880. 
h. 
m. 
h. 
m. 
0 
r. 
r. 
r. 
// 
// 
May 31 
l6 
7 
21 
31.° 
7i-5 
59.686 
Os 
00 
VO 
8.873 
44 
J3 
+ 
0.013 
2 
111. A. 
.658 
• 531 
•873 
44 
13 
.671 
• 563 
.892 
44 
23 
■657 
•553 
.896 
44 
25 
59■634 
68.548 
.914 
44 
34 
T = 
II* 
36m.2 
- 3' 
n.i 
68.551 
59.683 
.868 
44 
II 
AS = 
44' 
.201 
■563 
.666 
•897 
44 
25 
A p = 
+ 
O' 
.OI3 
•541 
•653 
.888 
44 
21 
± 
O' 
.047 
■550 
• 665 
.885 
44 
19 
l6 
32 
21 
56.0 
71.0 
,53g 
•659 
.880 
44 
17 
+ 
O.OI2 
June 2 
15 
50 
21 
13.2 
55-8 
68.587 
59.660 
8.927 
44 
40 
+ 
0.013 
2 
111. B. 
•579 
.617 
.962 
44 
57 
•574 
• 652 
.922 
44 
38 
•573 
.660 
•9I3 
44 
33 
68.580 
59-644 
•936 
44 
44 
T = 
IIh 
i3nl.6 
- 3 
“9 
59-653 
68.549 
.896 
44 
25 
AS - 
44' 
•33.3 
•649 
•55i 
.902 
44 
28 
Ap = 
+ 
o' 
■013 
•634 
.570 
•936 
44 
44 
r, = 
± 
0' 
.098 
.663 
•527 
.864 
44 
09 
l6 
21 
21 
44.2 
55-o 
.648 
•525 
•877 
44 
15 
+ 
0.013 
June 2 
16 
*4 
21 
47.2 
55-o 
68.510 
59-651 
8.859 
44 
06 
+ 
0.013 
2 
111. A. 
•533 
•693 
.840 
43 
97 
•537 
.682 
•855 
44 
04 
•567 
•657 
.910 
44 
32 
68.564 
59-658 
.906 
44 
3° 
T = 
II1' 
48m.o 
- 3 
”•9 
59.662 
68.538 
.876 
44 
15 
AS = 
44' 
.l6l 
.685 
■549 
.864 
44 
09 
Ap = 
+ 
O' 
•013 
.662 
• 526 
. .864 
44 
09 
rt = 
± 
O' 
.088 
• 
.668 
•569 
.901 
44 
27 
l6 
56 
22 
19.2 
54-7 
.649 
.560 
.911 
44 
32 
+ 
0.013 
June 17 
l6 
20 
21 
47.1 
68.5 
68.552 
59-675 
8.877 
44 
15 
+ 
0.012 
2 
111. A. 
•533 
.670 
• 863 
44 
08 
■548 
.678 
.870 
44 
12 
•545 
.701 
■844 
43 
99 
68.560 
59.666 
.894 
44 
24 
IOh 
44™-4 
o1 
n.o 
59.698 
68.505 
. 807 
43 
80 
AS - 
44' 
.060 
.671 
•524 
•853 
44 
°3 
Ap = 
+ 
O' 
.012 
.669 
•513 
.844 
43 
99 
r\ = 
± 
O' 
.085 
.699 
•548 
■849 
44 
OI 
16 
43 
22 
IO. I 
68.5 
.646 
•53° 
.884 
44 
19 
+ 
0.012 
June 18 
16 
22 
2T 
49.1 
71.0 
68.540 
59.663 
8.877 
44 
15 
+ 
0.012 
2 
111. A. 
•521 
•637 
.884 
44 
19 
•5” 
.669 
.842 
43 
98 
•555 
•649 
.906 
44 
3° 
68.545 
59-623 
.922 
44 
38 
T = 
IOh 
54,n-S 
0 
n.o 
59.648 
68.522 
•874 
44 
14 
AS = 
44' 
.146 
.670 
•531 
.861 * 
44 
07 
Ap = 
+ 
0' 
.012 
.683 
•54° 
•857 
44 
°5 
r, = 
± 
o' 
.099 
.699 
.529 
.830 
43 
92 
17 
9 
22 
36.1 
69.8 
■639 
•542 
•9°3 
44 
28 
+ 
0.012 
June 21 
16 
3i 
21 
58.0 
77.0 
68.562 
59.628 
8-934 
44 
44 
+ 
O.OII 
2 
111. A. 
•53i 
•654 
•877 
44 
15 
•539 
• 656 
.883 
44 
18 
•545 
•^97 
.848 
44 
OI 
68.563 
59.661 
.902 
44 
28 
T = 
10" 
4im.i 
— 0 
".I 
59-679 
68.539 
.860 
44 
°7 
AS = 
44' 
.165 
• 659 
.560 
.901 
44 
27 
Ap - 
+ 
0' 
.Oil 
.682 
•527 
•845 
43 
99 
= 
± 
o' 
.099 
.656 
•554 
.898 
44 
26 
16 
57 
22 
24.O 
77.0 
.681 
.528 
.847 
44 
OO 
+ 
O.OII THE PARALLAX OF a LYR.K AND 61 CYGNI. 
11 
Observations of a Lyras and Companion—Continued 
| Date. 
Clock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2A6 
AS 
Ap 
Wt. 
Remarks. 
1880. 
h. m. 
h. 
m. 
0 
r. 
r. 
r. 
„ 
n 
June 22 
16 49 
22 
15.9 
77 5 
68.554 
59-67° 
8.884 
44.19 
-f- O.OII 
3 
III. B. 
.556 
.660 
.896 
44 25 
•53* 
.681 
.850 
44.02 
.526 
.676 
.850 
44.02 
— 0**.2 
68.562 
59.691 
.871 
44.12 
H 
II 
\ 
ut 
3 
b 
59-647 
68.557 
.910 
44-32 
AS = 44".191 
.659 
.566 
.907 
44-3° 
Ap = 4" o".oi 1 
.667 
■572 
• 9°5 
44-29 
T| = + o".oj8 
.658 
.562 
.904 
44 29 
•7 9 
22 
35-9 
76.2 
.680 
.548 
.868 
44-II 
-)- O.OII 
June 22 
17 12 
22 
389 
76.2 
68.569 
59.642 
8.927 
44-4° 
4~ O.OII 
3 
111. A. 
•543 
.670 
.873 
44-13 
•543 
.689 
.854 
44.04 
•546 
.650 
.896 
44-35 
68.575 
59.681 
.894 
44.24 
r = nh is^-g 
— o".2 
59-66o 
68.544 
.884 
44.19 
AS = 44".172 
■673 
•539 
.866 
44.10 
Ap = 4" o".on 
.680 
.580 
.900 
44 27 
r, = ± o".o92 
.670 
■554 
.884 
44.19 
‘7 34 
*3 
0.9 
76.0 
.705 
•534 
.829 
43-91 
4- O.OII 
June 23 
16 4 
21 
30.8 
80.0 
68.569 
59-658 
8.911 
44-32 
+ O.OII 
2 
111. B. 
•57° 
.652 
.918 
44 36 
•557 
.640 
.917 
44-35 
•547 
.665 
.882 
44.18 
68.572 
59.669 
• 9°3 
44.28 
T — IOh 7m. I 
- °"-3 
59.620 
68.554 
•934 
44-43 
A« = 44"-279 
.642 
•552 
.910 
44-32 
Ap = 4- o".on 
.660 
•559 
• 899 
44.26 
II 
H- 
0^ 
*0 
00 
.678 
.580 
.902 
44.28 
16 32 
21 
58.8 
79 1 
.681 
•53° 
.849 
44.01 
-f- O.OII 
June 23 
•6 35 
22 
1.8 
79.0 
•68.542 
59.667 
8.875 
44 14 
4- O.OII 
3 
111. A. 
•572 
.687 
.885 
44.19 
•546 
.654 
.892 
44-23 
•553 
•649 
•9°4 
44.29 
68.518 
59.688 
.830 
43-92 
t — ioh 37m.o 
- °"3 
59-672 
68.554 
.882 
44.18 
AS = 44".204 
.654 
•565 
.911 
44-32 
Ap 4" o".ou 
•675 
■556 
.881 
44-17 
f| = ± o".o9o 
■635 
•569 
•934 
44-43 
>7 » 
22 
27.8 
78.5 
.661 
•541 
.880 
44 17 
4- O.OII 
June 24 
16 39 
22 
5-7 
82.0 
68.536 
59.667 
8.869 
44.11 
4- O.OII 
3 
111. B. 
•55° 
.662 
.888 
44.21 
Clouds. 
•527 
.650 
• 877 
44-15 
•549 
.639 
.910 
44-32 
- 0-.4 
68.521 
59-644 
.877 
44-15 
t = ioh 35l*.o 
59-63I 
68.587 
.056 
44-54 
AS = 44".262 
.648 
•563 
•9i5 
44-34 
Ap = 4- o".on 
.638 
•554 
.916 
44-35 
r 1 = ± o".o8g 
.651 
•53° 
.879 
44.16 
*7 1 
22 
27-7 
81.9 
.650 
•554 
.904 
44-29 
4- O.OII 
June 26 
16 6 
21 
32 5 
76.0 
68.531 
59-638 
8.893 
44-23 
4- O.OI2 
2 
111. B. 
•536 
.608 
.928 
44.40 
Clouds. 
•552 
•597 
•955 
44-54 
•53° 
•591 
'■939 
44 46 
— o“.6 
68.532 
59.629 
■9°3 
44.28 
T = 9k 59”-6 
59651 
68.539 
.888 
44.21 
A 6 = 44"-413 
.631 
.562 
•93i 
44.42 
Ap = 4" o".OI2 
.625 
•59° 
•965 
44-59 
r, = ± o".o94 
.654 
.619 
.965 
44-59 
16 39 
# 
22 
5-5 
76.0 
.638 
•565 
•927’ 
44-4° 
4- 0.012 12 
THE PARALLAX OF a LYR.E AND 61 CYGNI. 
Observations of a Lyrce and Companion-—Continued. 
Date. 
Clock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2 A6 
AS 
Ap 
Wt. 
Remarks. 
1880. 
h. m. 
h. 
III. 
•0 
r. 
r. 
r. 
,/ 
„ 
June 27 
15 45 
21 
11.4 
81.8 
68.550 
59.640 
8.910 
44-32 
-f- 0.012 
3 
111. A. 
•531 
.666 
.865 
44.09 
.546 
.661 
.885 
44^9 
•531 
.620 
.911 
44-32 
- om.7 
68.531 
59.640 
.891 
44.22 
T := 
9h 30m.o 
59657 
68.528 
.871 
44.12 
AS =z 
44".189 
.678 
•517 
•839 
43-96 
Ap = 
-j- o".OI2 
.651 
•54° 
.889 
44.21 
r, = 
+ o".074 
•654 
•54° 
.886 
44.20 • 
16 9 
21 
35-4 
81.0 
.602 
.501 
.899 
44.26 
-f- 0.012 
June 28 
16 8 
21 
34-3 
80.8 
68.546 
59.666 
8.880 
44.17 
0.012 
3 
111. A. 
.510 
.652 
.858 
44.06 
•554 
.659 
•895 
44.24 
•509 
.640 
.869 
44.n 
- o'".8 
68.513 
59-665 
.848 
44.01 
T — 
911 46'"-9 
59.660 
68.526 
.866 
44.10 
AS = 
44"-,3z 
.644 
•564 
.920 
44-36 
Ap = 
-|- Or/.OI2 
•675 
•514 
■839 
43-96 
r 1 = 
± o".IOI 
•637 
• 555 
.918 
44-36 
16 28 
21 
54-3 
80.5 
.684 
.520 
.836 
43-95 
-f- 0.012 
June 28 
16 31 
21 
57-3 
80.5 
68.569 
59-65I 
8.918 
44-36 
-f- O.OII 
3 
111. 11. 
•54° 
.678 
.862 
44.08 
•53° 
•7°5 
.825 
43-89 
•573 
.668 
•9°5 
44.29 
- o'".8 
68.572 
.662 
.910 
44-32 
T = 
ioh 9n'.9 
59.630 
68.542 
.912 
44-33 
AS =: 
44".230 
.649 
•55° 
.901 
44.27 
Ap z= 
+ o".OII 
•673 
•531 
.858 
44.06 
r, zz 
± o".iog 
•633 
•55i 
.918 
44-35 
16 51 
22 
17-3 
80.0 
•639 
• 555 
.916 
44-35 
-j- O.OII 
June 3c 
16 22 
21 
48.1 
76.8 
68.519 
59.660 
8.859 
44.06' 
-f- O.OII 
2 
111. A. 
•553 
• 659 
• 894 
44.24 
.578 
.636 
.942 
44.48 
•555 
.652 
•9°3 
44.28 
68.552 
59.660 
.892 
44.23 
T — 
9'' 55m-3 
— Im.O 
59.685 
68.550 
.865 
44.09 
AS zz 
44".209 
.670 
•5°3 
•833 
43-93 
Ap zz 
4- o,,.oii 
•639 
•545 
?9o6 
44-3° 
r 1 = 
± o".io3 
.656 
.562 
.906 
44.29 
16 47 
22 
131 
76.0 
.664 
•548 
.884 
44-!9 
-f- 0.011 
June 30 
16 52 
22 
l8. I 
76.0 
68.585 
59.672 
8-9!3 
44-33 
-J- O.OII 
2 
HI. B. 
.586 
.660 
.926 
44.40 
•575 
.666 
.909 
44-31 
•587 
.660 
.927 
44.40 
68.581 
59-650 
•93i 
44.42 
T — 
io1' 26"1.7 
— Im.O 
59.627 
68.556 
.929 
44.41 
AS zz 
44"-338 
.650 
•569 
.919 
44-36 
Ap = 
-f- o".on 
.666 
•565 
•899 
44.26 
r, zz 
-fc o".049 
•643 
•53i 
.888 
44.21 
17 20 
22 
46.1 
75-° 
.651 
•553 
.902 
44.28 
-j- O.OII 
July 3 
16 26 
21 
5i-9 
72-5 
68.558 
59.640 
8.918 
44-35 
-f- O.OII 
3 
111. B. 
.520 
.662 
.858 
44.06 
•548 
.668 
.880 
44.17 
•53i 
r68o 
■ 851 
44.02 
— Im. 2 
68.550 
•659 
.891 
44.22 
T — 
9h 48m.8 
59-647 
68.576 
.929 
44.41 
AS - 
44”.243 
\ 
.640 
•539 
.899 
44.26 
Ap zz 
-f- o".OIl 
.661 
•59° 
.929 
44.41 
n = 
± 0" .089 
.668 
.568 
.900 
44-27 
* 
16 54 
22 
19.9 
7r-7 
.669 
.568 
.899 
44.26 
-)- O.OII 
% THE PARALLAX OF a LYR.E AND 61 CYGNI. 
13 
Observations of a Lyras and Companion—Continued. 
Date. 
Clock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2AS 
AS 
Ap 
wt. 
Remarks. 
1880. 
h. 
111. 
h. 
m. 
r. 
r. 
r. 
// 
// 
July 
3 
l6 
57 
22 
22.9 
7'-7 
68.537 
59.640 
8.897 
44-25 
4- 
O.OII 
3 
III. A. 
•543 
.678 
.864 
44.09 
•540 
•655 
.885 
44-19 
•556 
.656 
.900 
44-27 
T = 
ioh 
l8m.2 
— 1 
■•3 
68.576 
59.681 
•895 
44-24 
AS = 
44' 
•'45 
59.683 
68.531 
.849 
44.01 
■V - 
+ 
O' 
.Oil 
.643 
.566 
.924 
44.38 
ri = 
± 
o' 
•095 
.680 
•542 
.862 
44.08 
.686 
•524 
.838 
43.96 
*7 
22 
22 
47-9 
70.9 
.686 
•528 
.842 
43-98 
+ 
0.011 
July 
26 
l6 
m 
31 
38.0 
82.5 
68.551 
59.656 
8.895 
44.24 
+ 
O.OII 
2 
111. B. 
•527 
.660 
.867 
44.10 
•55° 
.664 
.886 
44.20 
.548 
.653 
.895 
44.24 
~ 3 
■.I 
68-535 
59 657 
.878 
44.16 
T = 
8h 
4ni.o 
59.660 
68.524 
.864 
44.09 
AS = 
44' 
.l8l 
.670 
•550 
.880 
44'7 
Ap = 
+ 
O' 
.Oil 
.649 
•543 
•894 
44.24 
n = 
± 
O' 
.067 
.659 
•577 
.918 
44-36 
l6 
4' 
22 
5-o 
81.8 
.700 
•548 
.848 
44.01 
+ 
O.OII 
July 
27 
*7 
5 
22 
38.9 
76.6 
68.510 
59.664 
8.846 
44.00 
+ 
o.oll 
2 
111. A. 
•543 
•675 
.868 
44” 
•542 
.670 
.872 
44 '3 
•551 
.680 
.871 
44.12 
r = 
8h 
45m-3 
- 3 
".2 
68.530 
59-643 
.887 
44.20 
AS = 
44' 
.IOI 
59.640 
68.509 
.869 
44.11 
Ap = 
+ 
o' 
.Oil 
.669 
•531 
.862 
44.08 
r 1 = 
± 
0' 
•057 
.648 
•543 
•895 
44.24 
.660 
.520 
.860 
44.07 
>7 
21 
22 
44-9 
76.0 
.693 
•529 
.836 
43-95 
H- 
O.OII 
July 
38 
l6 
33 
21 
56.8 
CO 
59.669 
. 68.549 
8.880 
44.17 
+ 
O.OII 
2 
111. B. 
.661 
.560 
.899 
44.26 
■649 
• *3*3 
.864 
44.09 
.663 
.568 
.906 
44.30 
- 3 
-■3 
59.666 
68.546 
.880 
44'7 
T — 
8h 
'3“4 
68.561 
59.630 
•93' 
44-42 
AS = 
44' 
.225 
• 
•536 
.671 
.865 
44.09 
Ap _ 
+ 
o' 
.OH 
.560 
•657 
•903 
44.28 
n — 
± 
0' 
.072 
•535 
•657 
.878 
44.16 
l6 
57 
22 
30.8 
73-7 
.566 
.658 
.908 
44-3' 
+ 
O.OII 
July 
38 
•7 
O 
22 
23.8 
73-6 
59.676 
68.536 
8.860 
44.07 
+ 
O.OII 
2 
111. A 
.662 
•532 
.870 
44.12 
.661 
.520 
•859 
44.06 
.656 
•54' 
.885 
44.19 
T = 
8h 
39m-8 
- 3 
"•3 
59.667 
68.528 
.861 
44-07 
AS - 
44' 
•'33 
68.556 
59-657 
•899 
44.26 
Ap = 
+ 
o' 
.Oil 
•549 
.669 
.880 
44'7 
n = 
± 
0" 
•043 
•550 
.671 
•879 
44.16 
•551 
.672 
•879 
44.16 
'7 
»3 
22 
46.8 
73.8 
•53° 
.670 
.860 
44.07 
-1- 
O.OII 
July 
39 
l6 
5* 
22 
14.8 
75-o 
59-624 
68.576 
8.952 
44-52 
+ 
O.OII 
2 
111. B. 
.671 
•57' 
.900 
44.27 
.652 
•578 
.926 
44.40 
.642 
•555 
•9'3 
44-33 
T = 
8h 
32"-4 
~ 3 
“•3 
59.660 
68.581 
.921 
44-37 
AS = 
44' 
•327 
68.542 
59.622 
.920 
44.36 
Ap = 
+ 
O' 
.Oil 
•539 
•653 
.886 
44.20 
n = 
± 
O" 
.069 
•557 
•639 
.918 
44 36 
4 
•546 
•639 
.907 
44-3° 
l7 
25' 
22 
48.8 
73-3 
•538 
•659 
.879 
44.16 
+ 
O.OII 14 
THE PARALLAX OF a LYR.E AND 61 CYGNI 
Observations of a Lyroe and Companion—Continued. 
Date. 
Clock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2A8 
AS 
Ap 
Wt. 
Remarks. 
1880. 
h. m. 
h. 
m. 
0 
r. 
r. 
r. 
// 
,, 
July 30 
16 S3 
22 
16.7 
74-5 
68.520 
59.676 
8.844 
43-99 
-f- O.OII 
3 
111. A. 
•533 
•637 
.896 
44-25 
•559 
.681 
.878 
44.16 
■542 
.656 
.886 • 
44.20 
68.548 
59.676 
.872 
44-13 
T = 
8h 24m.9 
- 3n,-4 
59.681 
68.545 
.864 
44.09 
AS = 
44"-I37 
.678 
•563 
.885 
44.19 
Ap — -f- 
o".OII 
•653 
•5*4 
.861 
44 °7 
U = ± 
°"-°55 
•657 
•547 
.890 
44.22 
17 12 
22 
35-7 
73-9 
.674 
■535 
.861 
44.07 
-f- O.OII 
July 31 
17 17 
22 
40.6 
78.3 
59.640 
68.546 
8.906 
44-3° 
-f- O.OII 
2 
111. A. 
.682 
• 548 
.866 
44.10 
.626 
• 52° 
.894 
44.24 
.669 
.512 
.843 
43-98 
- 3m-5 
59-658 
68.548 
.890 
44.22 
T = 
8h 43m-8 
68.561 
59.648 
■913 
44-33 
AS = 
44"-17S 
• 550 
.660 
.890 
44.22 
Ap = + 
o".on 
.518 
•675 
• 843 
43 98 
D = ± 
o".o84 
* 
•534 
• 659 
.875 
44.14 
17 38 
23 
1.6 
77.8 
•55i 
.650 
.901 
44.27 
-(- O.OII 
Aug. 12 
17 16 
22 
38.8 
76.5 
59.66a 
68.534 
8.874 
44.14 
-|- O.OII 
2 
111. A. 
.64O 
•551 
.911 
44-32 
.644 
•549 
■9°5 
44.29 
.672 
•514 
.842 
43 98 
- 4m-3 
59.660 
68.550 
.890 
44.22 
T = 
7h 56"'.3 
68.522 
59.661 
.861 
44.07 
AS = 
44".107 
•509 
.662 
•847 
44.00 
Ap - + 
o".OII 
■539 
•695 
.844 
43-99 
D = ± 
o".o8y 
•521 
.664 
• 857 
44-°5 
17 40 
23 
2.8 
75-6 
.509 
.660 
.849 
44.01 
-f- O.OII 
Aug. 12 
19 26 
O 
48.8 
72-5 
68.556 
59.661 
8.895 
44.24 
-(- O.OII 
2 
111. B. 
•554 
.660 
.894 
44.24 
•55° 
.625 
.925 
44-39 
.560 
.663 
.897 
44-25 
68.566 
59.642 
.924 
44-38 
T = 
ioh 5m .9 
- 4m-3 
59.668 
68.558 
.890 
44-22 
AS -- 
44".274 
.658 
•55i 
• 893 
44-23 
Ap = + 
©".on 
.669 
.560 
.891 
44.22 
n = ± 
o".°43 
•644 
•552 
.908 
44-3' 
19 5° 
I 
12.8 
71.0 
.646 
•545 
•899 
44.26 
-(- O.OII 
Aug. 15 
l8 l6 
23 
38.5 
72.0 
68.548 
59-635 
8.913 
44-33 
-4- O.OII 
2 
111. A. 
•572 
.650 
.922 
44 38 
•565 
.663 
.902 
44.28 
•53° 
• 674 
.856 
44-°5 
- 4m.6 
68.506 
59.672 
•834 
43-94 
T = 
8h 47m-5 
59-656 
68.539 
.883 
44.18 
AS -- 
44”.184 
■659 
•552 
•893 
44-23 
Ap = + 
o".on 
.629 
•53° 
.901 
44.27 
r, = ± 
o".ioi 
•654 
•542 
.888 
44.21 
18 47 
O 
95 
70.5 
.667 
• 5°7 
.840 
43-97 
+ O.OII 
Aug. 16 
16 58 
22 
20.5 
73-5 
59.640 
68.544 
8.904 
44.29 
-f- O.OII 
3 
111. A. 
•679 
.567 
.888 
44-21 
Twilight. 
•644 
■530 
.886 
44.20 
.658 
•546 
.888 
44.21 
59.662 
68-537 
•875 
44.14 
T = 
7h i9m-3 
— 4m.6 
68.532 
59.646 
.886 
44.20 
AS = 
44".199 
• 552 
.669 
.883 
44.18 
Ap = + 
o".oii 
•569 
.641 
.928 
44.40 
r, = ± 
o".o64 
•539 
.679 
.860 
44.07 
17 16 
22 
38.5 
73-° 
•552 
.688 
.864 
44.09 
-|- O.OII THE PARALLAX OF a LYR.E AND 61 CYGNI. 
15 
Observations of a Lyrce and Companion—Continued. 
Date. 
('lock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Mies. 
2 A<$ 
AS 
Ap 
Wt. 
Remarks. 
1880. 
h. in. 
h. 
m. 
0 
r. 
r. 
r. 
// 
// 
Aun. >6 
17 21 
22 
43 5 
72.7 
59-674 
68.538 
8.864 
44-09 
-f- 0.012 
2 
111. H. 
.671 
•539 
.868 
44“ 
.680 
•529 
• 849 
44-oi 
.668 
•546 
.878 
44.16 
- 4".6 
59.642 
68.549 
•9°7 
44 3° 
r = 7k. 46“.9 
68.562 
59657 
.905 
44.29 
AS — 44".188 
•545 
.643 
.902 
44.28 
Ap =r -(- o".OI2 
•569 
.656 
.913 
44-33 
7*1 = db o".076 
.526 
.663 
.863 
44.08 
*7 48 
23 
10.5 
7«-5 
■55a 
.659 
•893 
44-23 
-4- 0.012 
Sept. 14 
«9 44 
I 
12.8 
59-7 
68-544 
59-641 
8.903 
44.28 
-(- 0.012 
2 
III. A. 
•5*4 
.616 
.898 
44.26 
Images very blazing 
.520 
.641 
•879 
44.16 
•55a 
•633 
•9*9 
44 36 
+ I--7 
68.530 
59631 
•899 
44.26 
t = 8k 25“.6 
59-593 
68.496 
.903 
44.28 
AS — 44".246 
.60I 
.522 
.921 
44-37 
Ap =r -|- o".oi2 
.624 
•489 
.865 
44.09 
T\ = ± o".059 
.615 
•498 
.883 
44.18 
20 19 
I 
47.8 
58.8 
.614 
•s°4 
.890 
44.22 
-(- 0.012 
Sept. 15 
19 42 
I 
10.9 
62.0 
59.630 
68.528 
' 8.898 
44.26 
-j- 0.012 
2 
III. A. 
•635 
•531 
.896 
44-25 
.640 
•537 
•897 
44 25 
.650 
.520 
.870 
44.12 
+ >"-8 
59.629 
68.549 
.920 
44 36 
r = 8k 17".3 
68.486 
59-631 
•855 
44.04 
AS - 44"-233 
•542 
.616 
.926 
44-4° 
Ap o".OI2 
• 5°2 
.626 
.876 
44-15 
= ± o".o72 
.520 
.619 
.901 
44-27 
20 12 
I 
40.9 
60.5 
.520 
.628 
.892 
44-23 
-J- 0.012 
Sept. 15 
20 15 
I 
43-9 
60.5 
59-644 
68.527 
8.883 
44.18 
-(- 0.012 
2 
111. B. 
•635 
•548 
•913 
44-33 
.638 
.511 
.873 
44.1.3 
.624 
.498 
.874 
44-M 
+ i". 8 
59.640 
68.533 
•893 
44-23 
r = 8k 46“. 7 
68.515 
59639 
.876 
44-15 
AS = 44". 185 
•554 
•659 
.895 
44-24 
Ap = -f- o".oi2 
.516 
■655 
.861 
44.07 
II 
H- 
0^ 
‘8! 
00 
•517 
•663 
.854 
44.04 
20 38 
2 
6.9 
59.6 
•53° 
.616 
.914 
44-34 
+ 0.012 
Sept. 16 
20 20 
I 
49.1 
65.0 
59-623 
68.485 
8.862 
44-°8 
-(- 0.012 
2 
111. B. 
•653 
•504 
.851 
44.02 
.600 
.521 
.921 
44-37 
• 
.665 
.526 
.861 
44-07 
-j- 2m.O 
59.609 
68.538 
.929 
44-41 
T = 8k 49" .0 
68.506 
59658 
.848 
44.01 
AS = 44”.165 
•540 
.640 
.900 
44-27 
Ap = -(- o".OI2 
.526 
.638 
.888 
44-21 
rt = ± o".o97 
•5°3 
.627 
.876 
44-15 
20 45 
2 
14.1 
64.5 
.511 
•653 
.858 
44.°6 
+ 0.012 
Sept. 17 
20 6 
, 
35-3 
74 6 
59.610 
68.515 
8.905 
44.29 
-f- O.OII 
2 
III. A. 
.646 
.506 
.860 
44.07 
.641 
•523 
.882 
44.18 
•657 
.522 
.865 
44.09 
-f 2-2 
59.644 
68.498 
•854 
44.04 
T = 8k 40™.2 
68.520 
59.630 
.89O 
44-22 
AS = 44".212 
.501 
•590 
.911 
44-32 
Ap = -f- o''.OI2 
.490 
.610 
.880 
44 • *7 
ri = + o".o84 
.521 
•592 
•929 
44-41 
20 49 
2 
18.3 
73° 
•543 
.631 
.912 
44-33 
+ 0.012 16 
THE PARALLAX OF a LYR.E AND 61 CYGNI 
Observations of a Lyras and Companion—Continued. 
Date. 
Clock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2 AS 
AS 
A P 
Wt. 
Remarks. 
1880. 
h. m. 
h. 
m. 
O 
r. 
r. 
r. 
„ 
„ 
Sept. 17 
20 54 
2 
23-3 
73-° 
59-644 
68.531 
8.887 
44.20 
+ 
0.012 
2 
111. B. 
.603 
•548 
•945 
44-49 
Images 
very blazing 
.632 
•526 
.894 
44.24 
and u 
nsteady. 
.613 
•545 
•932 
44.42 
+ 2n>.2 
59-637 
68.528 
.891 
44.22 
T = 
9h 25“'. 1 
68.500 
59-655 
•845 
43-99 
AS = 
44,,-I36 
•493 
•637 
.856 
44-05 
Ap = 
-j- o".oi2 
.484 
.680 
.804 
43-79 
n = 
± o".I52 
•515 
.646 
.869 
44-ii 
21 21 
• 0 
3 
00.3 
72.0 
•493 
■677 
.816 
43-85 
+ 
0.012 
Sept. 18 
19 8 
O 
37-4 
78.0 
68.539 
59-598 
8.941 
44-47 
+ 
0.0H 
3 
111. A. 
.526 
.612 
.914 
44-34 
# 
•524 
.628 
.896 
44-25 
•559 
.619 
.940 
44.46 
T = 
7h 26m.i 
+ 2m.3 
68.542 
59-657 
.885 
44.19 
AS - 
44".263 
59.632 
68.515 
.883 
44.18 
Ap = 
-f- o".on 
.632 
• 5*3 
.881 
44.17 
n = 
± o".o83 
■655 
.522 
.867 
44.10 
.651 
•547 
.896 
44-25 
19 26 
O 
55-4 
77.6 
.629 
•5i9 
.890 
44.22 
+ 
O.OII 
Sept. 18 
19 29 
O 
58.4 
77.6 
68.528 
59.620 
8.908 
44-31 
+ 
O.OII 
3 
111. B. 
•546 
.616 
.930 
44.42 
•555 
.620 
•935 
44.44 
T = 
7h 52m-5 
•634 
.879 
44.16 
AS — 
44"-342 
68.526 
59.620 
.906 
44.30 
Ap = 
+ o".OII 
+ 2 "'■3 
59.620 
68.554 
•934 
44.44 
n = 
± o".o6o 
.631 
•539 
.908 
44-31 
.640 
•54° 
.900 
44-27 
.636 
.561 
•925 
44-39 
19 58 
I 
27.4 
75-6 
.624 
■546 
.922 
44-38 
+ 
O.OII 
Sept. 22 
19 25 
O 
54-5 
66.5 
59.628 
68.500 
8.872 
44-13 
+ 
0.012 
3 
111. A. 
.611 
.506 
•895 
44.24 
.626 
■497 
.871 
44.12 
.650 
•54° 
.890 
44.22 
T = 
7h so1”.4 
+ 2"‘-4 
59.640 
68.519 
•879 
44.16 
AS = 
44"-249 
68.543 
59.608 
■935 
44-44 
Ap = 
+ o".OI2 
• 521 
.612 
.909 
44-31 
n = 
± o".o68 
.522 
.602 
.920 
44-36 
•531 
• 636 
.895 
44.24 
19 49 
I 
18.s 
65-8 
• 529 
.628 
.901 
44-27 
+ 
0.012 
Sept. 22 
19 52 
I 
21-5 
65.8 
59-631 
68.519 
8.888 
44.21 
+ 
0.012 
3 
111. B. 
.647 
•513 
.866 
44.10 
.634 
•537 
•9°3 
44.28 
.678 
•533 
■855 
44.04 
+ 2"'-4 
59-641 
68.536 
.895 
44.24 
T = 
7h 57“-8 
68.533 
59-634 
.«99 
44.26 
AS = 
44".217 
.516 
.610 
.906 
44-3° 
Ap = 
-p o”.Ol2 
.519 
.658 
.861 
44.07 
r\ = 
± o".075 
•537 
.628 
•9°9 
44-31 
20 17 
I 
46-5 
64.9 
.520 
.600 
.920 
44.36 
+ 
0.012 
Oct. 20 
>9 39 
I 
9-3 
56.5 
• 
59.629 
68.520 
8.891 
44.22 
+ 
0.012 
3 
111. A. 
.622 
.528 
.906 
44-30 
• 630 
•529 
.899 
44.26 
.618 
•513 
.895 
44.24 
T = 
5h 53”-1 
+ 3ra-2 
59-657 
68.538 
.881 
44.17 
AS = 
44"-'37 
68.488 
59.660 
.828 
43-91 
Ap « 
+ o".OI2 
• 
-518 
•644 
•874 
44.14 
r\ = 
3- o".09i 
■499 
•655 
• 844 
43-99 
.480 
.640 
.840 
43-97 
19 59 
I 
29.3 
55-8 
.510 
.629 
.881 
44 *7 
+ 
0.012 THE PARALLAX OF a LYR/E AND 61 CYGNI. 
17 
Observations of a Lyras and Companion—Continued. 
Date. 
Clock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2 AS 
AS 
Ap 
Wt. 
Remarks. 
1880. 
h. m. 
h. m. 
O 
r. 
r. 
r. 
// 
// 
Oct. 20 
20 4 
* 34-3 
55-8 
59-64° 
68.526 
8.886 
44.20 
4- 0.012 
3 
111. B. 
.625 
.526 
.901 
44-27 
.662 
•537 
• 875 
44-*4 
.624 
•54° 
.916 
44-35 
+ 3*a 
59-632 
68.555 
.923 
44-38 
t = 6k i9m.o 
68.539 
59.640 
.899 
44.26 
A8 = 44".230 
•5*4 
■644 
.870 
44.12 
Ap =: 4" o".OI2 
■547 
.640 
.907 
44 3° 
T\ = i o".o64 
•524 
.648 
.876 
44*5 
20 26 
1 56.3 
54-o 
•5*5 
.642 
•873 
44 *3 
-(- 0:012 
Oct. 24 
*9 43 
1 13.4 
46-5 
68.509 
59.629 
8.880 
44-*7 
4- 0.012 
3 
111. A. 
.518 
•653 
.865 
44-°9 
Windy. 
.521 
•63* 
.890 
44.22 
.520 
.628 
.892 
44-23 
+ 3"*3 
68.520 
59.620 
.900 
44-27 
r = 5h 41-5 
59-639 
68.535 
.896 
44-25 
AS = 44". 201 
.630 
.520 
.890 
44.22 
Ap = 4" o".OI2 
.638 
•524 
.886 
44.20 
Ti = ± o".o36 
.625 
.5*6 
.891 
44-22 
20 3 
* 33-4 
45-5 
.613 
.488 
.875 
44-*4 
4- 0.012 
Oct. 24 
20 8 
1 38.4 
45-5 
68.502 
59656 
8.846 
44.00 
+ 0.013 
3 
111. B. 
•539 
.613 
.926 
44-4° 
■53° 
.630 
.900 
44-»7 
.528 
.624 
.904 
44-39 
68.508 
59.620 
.888 
44.21 
H 
II 
On 
00 
vb 
+ 3“-3 
59-658 
68.539 
.881 
44-*7 
AS = 44"-183 
.646 
•5*9 
•873 
44-*3 
Ap = 4" o".oi3 
.630 
•493 
.863 
44.08 
r, = ± o".o79 
.620 
.504 
.884 
44*9 
20 33 
2 3.4 
45-2 
.656 
■52* 
.865 
44 °9 
4- 0.013 
Oct. 25 
19 50 
z 20.4 
49 5 
68.511 
59-64* 
6.870 
44.12 
4- 0.012 
3 
IU. A. 
•54* 
.646 
• 895 
44 24 
•5°3 
•633 
.870 
44.12 
•527 
•634 
•893 
44-23 
• 
+ 3"-3 
68.540 
59.642 
.898 
44.26 
T = 5k 43“-5 
59-632 
68.509 
•877 
44 *5 
AS = 44".162 
.646 
.492 
.846 
44.00 
Ap = 4" o".OI2 
.656 
.5*2 
.856 
44 °5 
r, — ± o".ooi 
.630 
.529 
.899 
44.26 
20 8 
I 38.4 
49.0 
• 655 
•539 
.884 
44-*9 
4 0.012 
Oct. 25 
20 IO 
I 40.4 
49.0 
68.515 
59-65* 
8.864 
44.09 
4- 0.012 
3 
111. B. 
■ 5°4 
.650 
.854 
44 °4 
•525 
.621 
.904 
44-39 
•S32 
.640 
.892 
44 23 
+ 3--3 
68.516 
59-64° 
.876 
44 *5 
r = 6k 6m.5 
59-639 
68.515 
.876 
44.15 
AS = 44".217 
.646 
•542 
.896 
44-25 
Ap = 4" o".oi2 
.628 
•55° 
.922 
44-37 
rt = ± o".o7i 
.640 
•544 
•9°4 
44-39 
20 34 
* 4-4 
48.5 
.631 
•539 
.908 
44-3* 
4- 0.012 
Oct. 31 
20 4 
1 31.8 
52.0 
59-634 
68.529 
8.895 
44-24 
4- 0.012 
3 
IU. A. 
•633 
•53* 
.898 
44.26 
•655 
.522 
.867 
44.10 
•633 
•547 
•9*4 
44-34 
+ °“-7 
59.638 
68.528 
.890 
44.22 
T = 5h 32”-8 
68.511 
59-639 
.872 
44 *3 
AS = 44".214 
•5** 
.644 
.867 
44 *0 
Ap = 4" o".oi2 
•542 
.626 
.916 
44-35 
rj = ± o".o6i 
•5*9 
•639 
.880 
44 *7 
20 25 
1 52.8 
5*-5 
•538 
.646 
.892 
44-23 
4- 0.012 18 
THE PARALLAX OF a LYRvE AND 61 CYGNI. 
Observations of a Lyrce and Comjyanion— Continued. 
Date. 
Clock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2 A<5 
AS 
Ap 
wt. 
Remarks. 
1880. 
h. m. 
h. m. 
0 
r. 
r. 
r. 
„ 
,, 
Oct. 31 
20 30 
1 57-8 
SI-S 
59-639 
68.534 
8.895- 
44.24 
0.012 
3 
111. B. 
•630 
.538 
.908 
44.31 
•643 
•507 
.864 
44.09 
.629 
.512 
.883 
44.18 
59.660 
68.542 
.882 
44.18 
T = 6h Om.2 
+ °m-7 
68.530 
59.641 
.889 
44.21 
AS = 44".167 
.516 
.639 
•877 
44-15 
Ap = -f- o".OI2 
.500 
■644 
.856 
44-°5 
r 1 = ± o".o52 
•524 
•657 
.867 
44.10 
20 54 
2 21.8 
51.0 
•527 
•649 
.878 
44.16 
-|- 0.012 
Nov. 1 
20 16 
1 43-8 
5i-5 
59.641 
68.522 
8.881 
44 17 
+ 0.012 
3 
111. A. 
.632 
•532 
.900 
44-27 
.640 
.501 
.861 
44.07 
.636 
•524 
.888 
44.21 
+ om.7 
S9-6i5 
68.524 
•9°9 
44-31 
r = 5k 36™.8 
68.529 
59-655 
•874 
44.14 
AS = 44".127 
•511 
.664 
•847 
44.00 
Ap = 0" .012 
.518 
•677 
.841 
43-97 
rt = ± o'7.076 
.527 
.669 
.858 
44.06 
20 29 
1 56-8 
51-0 
•525 
.665 
.860 
44.07 
-j- 0.012 
Nov. 1 
20 32 
1 59.8 
510 
59•662 
68.530 
8.868 
44.11 
4- 0.012 
3 
111. B. 
.670 
■53° 
.860 
44.07 
.672 
520 
.848 
44.01 
.664 
•SO 
• 853 
44-°3 
+ °m-7 
59-653 
68.511 
.858 
44.06 
T = 5h 55m-8 
68.514 
59-643 
.871 
44.12 
AS = 44".122 
•546 
• 656 
.890 
44.22 
Ap o".012 
.511 
•634 
.877 
44-15 
D = ± o".o57 
■53° 
.648 
.882 
44-i8 
20 51 
1 18.8 
50.0 
•551 
.650 
.901 
44-27 
-f- 0.012 
Nov. 2 
20 24 
1 Si-9 
55-5 
59.640 
68.498 
8.858 
44.06 
-(- 0.012 
2 
111. A. 
.668 
•521 
•853 
44-°3 
.648 
•483 
.835 
43-94 
•647 
•529 
.882 
44.18 
+ 
0 
a 
bo 
59 631 
68.531 
.900 
44.27 
T - 5h 43m-5 
68.511 
59.624 
.887 
44.20 
O? 
II 
4*- 
00 
.516 
.608 
.908 
44-31 
Ap = -|- o".OI2 
•544 
.640 
•9°4 
44.29 
r 1 = ± o".o83 
•493 
• 632 
.861 
44.07 
20 42 
2 9.9 
54-o 
•511 
•639 
.872 
44-13 
-(- 0.012 
Dec. 3 
21 43 
3 12-4 
38.0 
59.611 
68.500 
8.889 
44-21 
-f- 0.014 
3 
111. A. 
‘ -633 
•5i5 
.882 
44.18 
Twilight. 
.616 
•5°5 
.889 
44.21 
•637 
.490 
•853 
44-03 
59.640 
68.516 
876 
44-15 
r = 5h °m-4 
+ 2 ”'•3 
68.526 
59-643 
.883 
44.18 
Ad = 44"-i03 
9 
.484 
.648 
.836 
43-95 
Ap = -f- o".oi4 
•489 
.640 
.849 
44.01 
Vi = ± o".070 
.490 
.651 
839 
43-96 
21 58 
3 27.4 
37-6 
•53° 
•654 
.876 
44-15 
+ 0.014 
Dec. 3 
22 O 
3 29.4 
37-6 
59.632 
68.520 
8.888 
44.21 
-}- 0.014 
3 
111. B. 
.621 
•511 
.890 
44.22 
636 
•5°5 
.869 
44.11 
•634 
•5°5 
.871 
44.12 
59.644 
68.491 
.847 
44.00 
T = 5h 20m.8 
+ 2”-3 
68.493 
59.623 
.870 
44.12 
AS 44".ii4 
.510 
■ 625 
.885 
44.19 
Ap = + o".oi5 
■477 
.641 
.836 
43-95 
II 
H- 
0^ 
b 
Cn 
00 
.502 
.630 
.872 
44-13 
22 22 
3 5»-4 
36.7 
.505 
.641 
.864 
44.09 
+ 0015 THE PARALLAX OF a LYRvE AND 61 CYGNI. 
19 
Observations of a Lyr<r and Companion—Continued. 
Date. 
Clock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2 A6 
A< 
Ap 
Wt. 
Remarks. 
1880. 
h. in. 
h. m 
D 
r. 
r. 
r. 
n 
// 
Dec. 7 
21 58 
3 37-8 
23.0 
68.519 
59-667 
8.852 
44-°3 
+ 0.014 
2 
111. A. 
•549 
.640 
.909 
44-3* 
Twilight. 
•536 
.656 
.880 
44-17 
•552 
.672 
.880 
44- *7 
+ a"7 
68.548 
59.656 
.892 
44-23 
r = 5‘ >“-5 
59-658 
68.521 
.863 
44.08 
A« = 44”-i33 
.696 
.526 
.830 
43.92 
Ap = -|- o".oi5 
.642 
•527 
.885 
44 >9 
rt = ± o".o73 
.652 
•524 
.872 
44-*3 
22 16 
3 45-8 
22.5 
.643 
■509 
.866 
44.10 
-f 0.015 
Dec. 9 
22 9 
3 39 0 
24.O 
59.628 
68.493 
8.865 
4409 
+ oo'4 
a 
111. A 
.601 
•509 
.908 
44-31 
.620 
•456 
.836 
43-95 
.624 
•495 
•871 
44.12 
1 a".9 
59.621 
68.503 
.882 
44.18 
T ~ 5h 5“-3 
68.510 
59.621 
.889 
44.21 
A8 = 44".125 
.502 
.632 
.870 
44.12 
Ap =r -(- o".oi5 
.508 
.640 
.868 
44“ 
r, = ± o".o8o 
.472 
.640 
.832 
43-93 
22 28 
3 58.0 
*3-5 
.520 
.628 
.892 
44-23 
+ 0-015 
Dec. 9 
22 30 
4 0.0 
*3-5 
59-650 
68.500 
8.850 
44.02 
+ 0.015 
a 
111. B. 
•634 
. -489 
.855 
44.04 
.628 
■503 
•875 
44 14 
.630 
•5» 
.881 
44 17 
+ 2®.9 
59627 
68.507 
.880 
44-17 
r = 5k 28“.7 
68.491 
59-639 
.852 
44 03 
A8 = 44"-049 
.508 
.680 
.828 
43-91 
Ap = -f- o".oi6 
.501 
.664 
■837 
43-95 
r, = ± o''.059 
.490 
.640 
.850 
44.02 
22 54 
4 24.0 
22.8 
.511 
.657 
.854 
44-°4 
-f- 0.016 
Dec. 11 
22 15 
3 45-1 
29.4 
68.502 
59.618 
8.884 
44-19 
+ 0.014 
3 
111. A. 
•5*3 
.620 
• 893 
44-23 
•5*3 
■647 
.866 
44.10 
.501 
.622 
.879 
44.16 
+ 3"° 
68.515 
59.612 
•9°3 
44.28 
r = 5h o®.5 
59.660 
68.481 
.821 
43-87 
A« = 44,,-i37 
.630 
.490 
.860 
44 07 
Ap = -f- o”.oi5 
.618 
.505 
.887 
44.20 
r, = ± o".o78 
.638 
.501 
.863 
44-°8 
22 28 
3 58.1 
28.6 
.622 
.507 
.885 
44-19 . 
+ 0.015 
Dec. 11 
22 30 
4 °-i 
28.6 
68.493 
59.666 
8.827 
43.90 
-f 0.015 
a 
111. B. 
.510 
.647 
.863 
44-°8 
.496 
.665 
.831 
43-92 
■494 
.650 
.844 
43-99 
68.483 
59.666 
.817 
43-85 
r = 5k i7m-o 
f 3* 0 
59.670 
68.513 
.843 
43 98 
A« = 44"-°37 
.616 
.500 
.884 
44-19 
Ap = -f" o".oi6 
.642 
•508 
.866 
44.10 
r, = ± o".o88 
.631 
.529 
.898 
44.26 
22 46 
4 16.1 
28.2 
.620 
.486 
.866 
44.10 
4- 0.016 
Dec. 13 
22 27 
3 57-3 
4i-y 
59.622 
68.486 
8.864 
44.09 
+ 0.015 
2 
111. A. 
.640 
.490 
.850 
44.02 
636 
.469 
•833 
43-93 
.630 
•497 
.867 
44.10 
+ 3"-a 
59-647 
68.480 
•833 
43-93 
r = 5k 8m.3 
68.469 
59.602 
.867 
44.10 
Ai = 44".005 
•448 
.613 
•835 
43-94 
Ap = -\~ o".oi6 
, 
•463 
.641 
.822 
43-88 
Tj — ± o".o56 
•473 
.610 
.863 
44-08 
22 47 
4 17-3 
40.0 
.490 
•647 
.843 
43-98 
-f- 0.016 20 
THE PARALLAX OF a LYRvE AND 6r CYGNI. 
Observations of a Lyce and Companion—Continued. 
Date. 
Clock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2A5 
AS 
Ap 
wt. 
Remarks. 
1880. 
h. m. 
h. m. 
0 
r. 
r. 
r. 
„ 
tt 
Dec. 13 
22 49 
4 19-3 
40.0 
59-617 
68.499 
8.882 
44.18 
-)- 0.016 
2 
111. B. 
•584 
•483 
.899 
44.26 
.669 
.518 
•849 
44.01 
.632 
•494 
.862 
44.08 
T = 5I> 3Im.3 
59.610 
68.469 
.859 
44.06 
AS = 44". 120 
+ 3m-2 
68.500 
59.604 
.896 
44-25 
Ap — -f o".oi7 
.483 
•643 
.840 
43-97 
n = + o".o6g 
•S°9 
.621 
.888 
44.21 
•5” 
.636 
•875 
44 •I4 
23 11 
4 4i-3 
39-5 
.486 
• 632 
•854 
44.04 
4- 0.017 
Dec. 15 
22 40 
4 io-4 
4i-5 
59.628 
68.459 
8.831 
43-92 
4- 0.015 
2 
111. A. 
.658 
.482 
.824 
43-89 
.646 
.488 
.842 
43 98 
.632 
.470 
•.838 
43.96 
II 
M 
S 
b 
4 3m-3 
59-617 
68.474 
.857 
44-05 
AS = 44".022 
68.478 
59.624 
•854 
44.04 
Ap = 4 o".oi6 
• 444 
•644 
.800 
43-77 
T\ = ± o".I02 
.482 
.582 
.900 
44.27 
.482 
•597 
.885 
44.19 
22 57 
4 27.4 
41.0 
.498 
.622 
.876 
44-15 
4- 0.016 
Dec. 16 
22 40 
4 10-5 
40.0 
68.508 
59-654 
8.854 
44.04 
4- 0.015 
3 
111. A. 
-516 
.622 
.894 
44.24 
•494 
.620 
•874 
44.14 
.478 
•639 
•839 
43.96 
T — 5h 6”.7 
68.482 
59.601 
.881 
44.17 
AS — 44,/.o4o 
+ 3n'-4 
59-647 
68.480 
.833 
43-93 
Ap = 4- o".oi6 
.618 
.482 
.864 
44.09 
T1 = ± o".o77 
.620 
•458 
.838 
43-96 
.628 
-452 
.824 
43-89 
22 54 
4 24.5 
39-o 
.6ll 
•454 
.843 
43-98 
4- 0.016 
Dec. 16 
22 57 
4 27.5 
39-o 
68.495 
59-597 
8.898 
44.26 
4- 0.016 
3 
111. B. 
•5°i 
.624 
•877 
44-15 
•493 
.616 
•877 
44-15 
• 5°4 
.623 
.881 
44-17 
r — 51' 25m.2 
+ 3m-4 
68.480 
59.644 
.836 
43-95 
AS = 44”-i37 
59-64I 
68.500 
• 859 
44.06 
Ap = 4 o".oi7 
.630 
.502 
.872 
44-13 
ri = ± o".os6 
.618 
•503 
.885 
44-*9 
.638 
.516 
.878 
44.16 
23 M 
4 44 5 
38-5 
.620 
•496 
.876 
44-15 
4 0.017 
Dec. 18 
22 S3 
4 19-9 
35-5 
59-634 
68.496 
8.862 
44.08 
4- 0.016 
2 
111. A. 
.620 
•495 
•875 
44.14 
.623 
•5°3 
.880 
44-17 
.612 
•477 
.865 
44.09 
— Om.2 
59-654 
68.497 
.843 
43-98 
t = 5h 9m.7 
68.480 
59-638 
.842 
43-98 
AS = 44".052 
.500 
.669 
.831 
43-92 
Ap = 4 o".oi6 
-451 
.582 
.869 
44.11 
ri = ± o".o69 
.520 
.641 
.879 
44.16 
23 IO 
4 36-9 
35° 
.448 
.623 
825 
43-89 
4- 0.017 
Dec. 18 
23 12 
4 38.9 
35-o 
59.603 
68.489 
8.886 
44.20 
4- 0.017 
2 
111. B. 
.631 
.458 
.827 
43-9° 
.6ll 
.470 
•859 
44.06 
• 
.601 
•5°7 
.906 
44-3° 
T = 5h 29m.7 
— Ora.2 
59.629 
68.482 
•853 
44-°3 
AS = 44".016 
68.444 
59.656 
.788 
43-71 
Ap = 4 o".oi8 
.480 
•633 
.847 
44.00 
ri = ± o".io7 
.461 
.621 
.840 
43-97 
» 
.516 
.666 
.850 
44.02 
23 31 
4 57-9 
34° 
•5<?3 
.663 
.840 
43-97 
4- 0.019 THE PARALLAX OF a LYRyE AND 61 CYGNI. 
21 
Observations of a Lyrce and (Companion—Continued. 
Date. 
Clock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2A8 
A5 
Ap 
Wt. 
Remarks. 
1880. 
h. m. 
h. 
m. 
O 
r. 
r. 
r. 
t» 
Dec. 32 
23 II 
4 
38.0 
32.7 
68.529 
59.671 
8.858 
44.06 
+ 0.017 
2 
111. B. 
•S5° 
•654 
.896 
44-25 
.500 
.664 
.836 
43-95 
.511 
•633 
.878 
44.16 
T = 5k 13" 0 
— o~.i 
68.472 
59.627 
.845 
43-99 
A« = 44"-°53 
59-59i 
68.484 
•893 
44-23 
Ap =: -|- o".oi8 
.630 
.472 
.842 
43-98 
r 1 = ± o".o8i 
.614 
•440 
.826 
43-9° 
• 
•599 
•449 
.850 
44.02 
*3 3° 
4 
57-o 
31-5 
.618 
.462 
.844 
43-99 
-f- 0.019 
1881. 
Keb. 6 
15 22 
20 
5°-3 
8.7 
59-6ii 
68.544 
8.933 
44-43 
+ 0.015 
I 
111. B. 
.614 
•536 
.922 
44 38 
Images very blazing 
.612 
•5°5 
8.893 
44-23 
and unsteady. 
.503 
•535 
9.032 
44.92 
+ 1-2 
59-604 
68.527 
8.923 
44 38 
r = i8h 23".8 
68.520 
59-633 
.887 
44-20 
Ai = 44”-342 
.470 
.568 
.902 
44.28 
Ap = -|- o".oi5 
•539 
.618 
.921 
44-37 
Tl = + o".j6o 
•472 
.623 
•849 
44.01 
>5 4S 
21 
*3-3 
8.0 
•493 
• 603 
.890 
44.22 
+ 0015 
Keb. 10 
IS 23 
20 
Si-2 
340 
59.630 
68.534 
8.904 
44-29 
-f 0.014 
3 
111. A. 
.600 
.529 
•929 
44 41 
.611 
•520 
.909 
44-31 
•589 
.510 
.921 
44-37 
r = i8h la^.o- 
59.632 
68.564 
.932 
44-42 
A« = 44"-3°7 
+ i".i 
68.511 
59-594 
•917 
44-35 
Ap = -f- o".oi4 
.480 
.580 
.900 
44-27 
n = ± o".059 
.511 
.604 
.907 
44-3° 
•459 
•584 
•875 
44-14 
is 5* 
21 
20.2 
33.6 
•484 
■595 
.889 
44.21 
+ 0014 
Keb. 12 
15 22 
20 
50.1 
31.0 
59-6ii 
68.521 
8.910 
44-32 
+ 0-014 
2 
111. B. 
.582 
•539 
•957 
44-55 
.620 
•527 
.907 
44-3° 
•564 
•558 
•994 
44 73 
T = i8h 5m.o 
-f- Im.O 
59.612 
68.541 
•929 
44-41 
A8 = 44"-384 
68.476 
59-586 
.890 
44.22 
Ap = -f- o'\oi4 
•533 
.600 
•933 
44-43 
ri = ± o".io5 
.518 
.621 
•897 
44-25 
•536 
.619 
.917 
44-35 
IS ss 
21 
23.1 
30.6 
.510 
.608 
.902 
44.28 
+ 0.014 
Keb. 13 
IS 35 
21 
3° 
26.8 
59.622 
68.482 
8.860 
44-°7 
4- 0.014 
2 
III. A. 
.586 
■521 
•935 
44-44 
.627 
•53° 
•9°3 
44.28 
•654 
•574 
.920 
44-36 
59.621 
68.507 
.886 
44.20 
t = i8h 9m.o 
4- o".9 
68.506 
59-594 
.912 
44-33 
A8 = 44"-259 
•494 
.612 
,882 
44.18 
Ap = -|- o".oi4 
•536 
•637 
• 899 
44.26 
ri = ± o”.o73 
.548 
.640 
.908 
44-31 
IS 58 
21 
26.0 
26.4 
.490 
.612 
.878 
44.16 
+ 0.014 
Keb. 14 
is 17 
20 
45.0 
22.8 
68.511 
59-633 
8.878 
44.16 
+ 0.014 
3 
111. B. 
.518 
.632 
.886 
44.20 
•53° 
.6ll 
.919 
44 36 
•536 
.614 
.922 
44-38 
r = M7k 46". 1 
4- o“-9 
68.524 
59-607 
.917 
44-35 
A5 = 44".250 
59 642 
68.506 
.864 
44.09 
Ap = o".oi4 
.625 
•529 
.904 
44 29 
ri = ± o".075 
• 632 
.506 
• 874 
44-14 
.640 
.518 
.878 
44.16 
»s 38 
21 
6.0 
22.5 
.6ll 
•533 
.922 
44-37 
+ o-oi4 THE PARALLAX OF a LYR2E AND 61 CYGNI. 
22 
Observations of a Lyrce and Companion—Continued. 
Date. 
Clock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2 AS 
AS 
Ap 
Wt. 
Remarks. 
1881. 
Feb. 14 
h. m. 
iS 4° 
h. m. 
21 8.0 
22.5 
r. 
68.507 
r. 
59-631 
r. 
8.876 
44-15 
-)- 0.014 
3 
111. A. 
.498 
.619 
.879 
44.16 
.498 
■623 
•875 
44.14 
•497 
.656 
.841 
43-97 
68.502 
59.600 
.902 
44.28 
r = i8h 8m.o 
+ °m.9 
59-649 
68.532 
.883 
44.18 
AS = 44".168 
• 653 
• 53° 
■877 
44-15 
Ap = o".oi4 
.621 
.526 
•9°5 
44.29 
f\ = H- o".os9 
.640 
.522 
.882 
44.18 
* 
15 59 
21 27.0 
22.0 
.642 
• 524 
.882 
44.18 
-(- 0.014 
Feb. 16 
IS 13 
20 4O.9 
25.0 
68.557 
59-6i7 
8.940 
44.46 
-f- 0.014 
3 
111. B. 
■477 
.613 
.864 
44.09 
• 546 
.624 
.922 
44.38 
•525 
.62a 
• 905 
44.29 
• 499 
.610 
.889 
44.21 
r = I711 36m.i 
+ om.8 
59.600 
68.522 
.922 
44-37 
AS =: 44".286 
.622 
• 524 
.902 
44.28 
Ap = -(- o',.oi4 
.604 
.490 
.886 
44.20 
T1 -= ± o".072 
.622 
• 518 
.896 
44.25 
15 38 
21 5-9 
24.6 
.602 
.516 
.914 
44-33 
0.014 
Feb. 16 
IS 40 
21 7.9 
24.6 
68.484 
59-6i4 
8.870 
44.12 
-f- 0.014 
3 
111. A. 
• 53° 
.619 
•9“ 
44-32 
■512 
.621 
.891 
44.22 
•5°7 
.620 
.887 
44.20 
68.507 
59.614 
.893 
44-23 
r = i8h 3m.o 
+ om.8 
59.628 
68.514 
.886 
44.20 
AS = 44".240 
.623 
.520 
.897 
44-25 
Ap = -)- o".oi4 
.629 
■517 
.888 
44.21 
r, = ± o".o45 
.624 
•535 
.911 
44-32 
16 5 
21 329 
24-3 
.624 
■537 
• 9i3 
44-33 
-)- 0.014 
Feb. 19 
15 7 
20 34.6 
28.0 
59-632 
68.528 
8.896 
44-25 
+ 0.014 
3 
111. B. 
.598 
•5i5 
.917 
44-35 
.607 
•534 
• 927 
44.40 
• 593 
• 536 
•943 
44.48 
59.611 
68.518 
.907 
44-3° 
T = I7h 20ni.5 
+ °ra-5 
68.505 
59.622 
.883 
44.18 
AS = 44".295 
.508 
.6ll 
.897 
44-25 
Ap o".oi4 
•51° 
.621 
.889 
44.21 
= ± 0" .062 
.528 
.630 
.898 
44.26 
15 37 
21 4.6 
27.8 
•518 
.618 
.900 
44-27 
-f- 0.014 
Feb. 19 
IS 39 
21 6.6 
27.8 
59-607 
68.510 
8.903 
44.28 
+ 0.014 
3 
111. A. 
.621 
.526 
• 9°5 * 
44.29 
.607 
•519 
.912 
44-33 
•598 
■ 515 
.917 
44-35 
59.618 
68.529 
.911 
44-32 
II 
M 
Crt 
0 
2 
+ °ro-5 
68.530 
59-632 
.898 
44.26 
AS — 44"-297 
.531 
•596 
•935 
44-44 
Ap = -f- o,/.oi4 
.518 
.636 
.882 
44.18 
Ti = ± o".o47 
•521 
•52° 
.901 
44.27 
16 5 
21 32.6 
27.2 
.528 
.632 
.896 
44-25 
+ 0.014 
Feb. 21 
IS 12 
20 39.4 
29.O 
59-6i3 
68.549 
8.936 
44-44 
-)- 0.014 
3 
111. B. 
.615 
•551 
•936 
44-45 
.614 
•519 
•9°5 
44.29 
.602 
■535 
•933 
44-43 
59.617 
68.540 
•923 
44-38 
T = I711 I5In.O 
+ o“.3 
68.511 
59.624 
.887 
44.20 
AS = 44".289 
.508 
.617 
.891 
44.22 
Ap = -(- o".oi4 
• 
.526 
.646 
,880 
44.17 
74 = ± o".o85 
•492 
.624 
.868 
44.11 
j • IS 37 
21 4-4 
28.8 
•5°7 
.620 
.887 
44.20 
+ 0.014 THE PARALLAX OF a LYR,E AND 61 CYGNI. 
23 
Observations of a Lyrce and Companion—Continued. 
Date. 
Clock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2A6 
AS 
Ap 
Wt. 
Remarks. 
1881. 
h. m. 
h. 
111. 
0 
r. 
r. 
r. 
„ 
n 
Feb. 21 
15 40 
21 
7-4 
28.8 
59-599 
68.518 
8.919 
44 36 
+ 0.014 
3 
111. A. 
.610 
.522 
.912 
44-33 
.607 
•507 
.900 
44-27 
.6ll 
•515 
•904 
44-29 
+ 0-.3 
59-598 
68.510 
.912 
44-3* 
T = I7k 40".9 
68.501 
59-632 
.869 
44.11 
AS — 44".290 
.522 
.607 
•915 
44-34 
Ap = -(- o".oi4 
•530 
.621 
.909 
44-31 
r, = ± o".o5i 
•53° 
.614 
.916 
44-35 
16 1 
21 
28.4 
28.5 
•501 
.610 
.891 
44-22 
+ 0.014 
Mar. 14 
«5 31 
20 
57° 
33-8 
59.616 
68.526 
8.910 
44-32 
4- 0.014 
3 
111. B. 
•578 
.526 
•948 
44-5° 
.621 
•534 
•913 
44-33 
.580 
•534 
•954 
44-54 
59.609 
68.528 
.919 
44-36 
T = i6h n,n.4 
- i".i 
68.518 
59632 
.886 
44.20 
A4 = 44"-387 
'5a4 
•579 
•945 
44-49 
Ap = -)- o".oi4 
.518 
.600 
.918 
44-36 
r, = ± o".077 
■529 
.628 
.901 
44-27 
15 59 
21 
25*° 
33-5 
•519 
•571 
.948 
44.50 
4- 0.014 
Mar. 14 
16 2 
21 
28.0 
33-5 
59.609 
68.498 
8.889 
44.21 
4- 0.014 
2 
111. A. 
•639 
•498 
•859 
44.06 
.609 
•538 
.929 
44 41 
• 634 
493 
•859 
44.06 
- 1”.1 
59-598 
68.505 
.907 
44-3° 
r = i6h 40*.9 
68.534 
59.611 
•923 
44-38 
A4 = 44"-193 
518 
.646 
.872 
44 13 
A P = + o".ox4 
•527 
•637 
.890 
44.22 
ri = ± 0" .090 
-500 
.644 
.856 
44.05 
16 27 
21 
53 0 
33 0 
•504 
•635 
.869 
44.11 
4 0.014 
Mar. 15 
15 26 
20 
51.9 
38.8 
59-6x8 
68.536 
8.918 
44 36 
+ 0.014 
3 
111. B. 
•597 
•538 
.941 
44-47 
.650 
.558 
.908 
44-31 
•59° 
.520 
• 93° 
44-41 
59-599 
68.524 
.925 
44-39 
T — x61’ om.4 
— 1".2 
68.530 
59-590 
.940 
44.46 
A6 — 44"-36o 
•525 
.614 
.911 
44-32 
Ap = -)- o".oi4 
'523 
•613 
.910 
44-32 
r, = i o".o47 
■5M 
.610 
.904 
44 29 
*5 5° 
21 
15-9 
38.5 
.520 
.619 
.901 
44-27 
4- 0.014 
Mar. 15 
15 52 
2X 
17.9 
38.5 
59.608 
68.497 
8.889 
44.21 
4- 0.014 
2 
111. A. Images blurred. 
.611 
.508 
•897 
44-25 
.609 
.5x8 
• 909 
44-31 
.628 
.520 
.892 
44-23 
59.611 
68.527 
.916 
44-35 
T — I61* 25m.<) 
— I®.2 
68.548 
59-575 
■973 
44-63 
AS = 44”.324 
— 
•513 
•637 
.876 
44 15 
Ap = -|- o".oi4 
•S32 
.618 
.914 
44-34 
»‘i — ± o".C90 
-550 
.622 
.928 
44.40 
16 15 
21 
40.9 
38-5 
.528 
.607 
.921 
44 37 
4- 0.014 
Mar. 21 
15 31 
20 
56.4 
34.0 
68-535 
S9-592 
8-943 
44 48 
+ 0.014 
, 2 
111. B. 
•536 
.582 
•954 
44-54 
.490 
.578 
.912 
44-33 
•569 
.581 
.988 
44.70 
- **-7 
68.548 
59.612 
•936 
44.44 
II 
Cn 
f- 
3 
GC 
59-599 
68.517 
•913 
44 36 
AS = 44"-442 
•591 
.521 
•930 
44-41 
Ap — -f- o".oi4 
.600 
•Si2 
.912 
44-33 
*"l = ± 0" .078 
.606 
.522 
.916 
44-35 
L_ 
15 58 
21 
33-4 
34° 
.602 
•546 
•944 
44 48 
+ 0.014 24 
THE PARALLAX OF a LYRyE AND 61 CYGNI. 
Observations of a Lyrce and Companion—Continued. 
Date. 
Clock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2AS 
AS 
Ap 
Wt. 
Remarks. 
1881. 
h. m. 
h. 
m. 
0 
r. 
r. 
r. 
// 
// 
Mar. 21 
16 2 
21 
27.4 
34-o 
68.537 
59612 
8.925 
44-39 
-(- 0.014 
2 
111. A. 
•514 
.582 
•932 
44.42 
.560 
.610 
•950 
44.51 
•512 
.629 
.883 
44.18 
T — 
l6h I2m.2 
68.482 
59.607 
.875 
44.14 
AS = 
44"-335 
- i“*.7 
59.620 
68.530 
.910 
44-32 
Ap = 
-f- o".oi4 
.629 
•53° 
.901 
44-27 
n = 
± o".oj6 
.603 
.520 
•9*7 
44-35 
.610 
•540 
•93° 
44.42 
16 26 
21 
51.4 
34-3 
.610 
•527 
.917 
44-35 
-f- 0.014 
Mar. 23 
16 7 
21 
32-3 
33-5 
68.521 
59-623 
8.898 
44.26 
-f- 0.0x4 
2 
111. B. 
•571 
.608 
.963 
44.58 
.528 
.638 
.890 
44.22 
•536 
.615 
.921 
44-37 
T = 
i6h 7m.3 
- iul.8 
68.530 
59-619 
.911 
44-32 
AS = 
44"-34* 
59-589 
68.523 
•934 
44-44 
Ap = 
+ o".oi4 
■592 
•53° 
•938 
44.46 
n = 
-t o".o8g 
.616 
.502 
.886 
44.20 
.630 
•5** 
.881 
44.17 
16 27 
21 
52.3 
33-° 
.605 
•53i 
.926 
44-39 
+ 0.013 
Mar. 23 
i6' 30 
21 
55-3 
33° 
68.497 
59-634 
8.863 
44.08 
+ 0.013 
2 
111. A. 
•538 
.623 
•9i5 
44-34 
•513 
.615 
.898 
44.26 
•503 
.627 
.876 
44-*5 
T = 
i6h 28,n.7 
68.528 
59.628 
.900 
44-27 
AS = 
44"-300 
“ im'8 
59-612 
68.525 
•913 
44-33 
AS = 
+ o".oi3 
.607 
•553 
•946 
44-49 
ri -- 
± o".079 
.600 
.520 
.920 
44-36 
.600 
•5M 
•9I4 
44-34 
16 47 
22 
12.3 
32-7 
.607 
•531 
•924 
44-38 
+ 0-013 
Mar. 26 
16 10 
21 
35-i 
31.8 
59-599 
68.530 
8.931 
44.42 
+ 0.014 
2 
111. B. 
•574 
•548 
•974 
44-63 
•597 
•527 
•93° 
44.42 
•599 
.566 
•967 
44.60 
r - 
i6h om,8 
— 2m.O 
59.600 
68.547 
•947 
44-50 
AS - 
44”-462 
68.538 
59.621 
.917 
44-35 
AP = 
+ o".oi4 
•549 
.600 
•949 
44-5* 
ri — 
± o".073 
•552 
.603 
•949 
44-5* 
•539 
.614 
•925 
44-39 
*6 35 
22 
O.I 
3i-5 
•53° 
.626 
•9°4 
44.29 
+ 0.014 
Mar. 26 
16 38 
22 
31 
3i-5 
59.614 
68.500 
8.886 
44.20 
+ 0.013 
2 
111. A. 
.614 
•532 
.918 
44-36 
.600 
•523 
•923 
44.38 
.614 
•519 
•9°5 
44.29 
T = 
I61* 27‘".7 
59.603 
68.518 
•9*5 
44-34 
AS = 
44,,-327 
— 2“,0 
68.511 
59.610 
.901 
44-27 
Ap = 
+ o".oi3 
•536 
.613 
•923 
44 38 
n — 
± o".o53 
•531 
.587 
•944 
44.48 
•524 
.620 
•9°4 
44.29 
17 I 
22 
26.1 
31.0 
• 520 
.617 
.903 
44.28 
+ 0.013 
Mar. 27 
l6 IO 
21 
35-o 
33-° 
68.536 
59.610 
8.926 
44.40 
. -j- 0.014 
3 
111. B. 
•533 
.600 
•933 
44-43 
•544 
.614 
•93° 
44.42 
•546 
.601 
•945 
44-49 
T — 
*5h 57m-2 
— 2n,.I 
68.512 
59-596 
.916 
44-35 
AS = 
44,r-385 
59-599 
68.498 
.899 
44.26 
Ap = 
+ o".oi4 
.632 
.523 
.891 
44.22 
n = 
.4; o".o62 
.603 
•S32 
•929 
44.41 
.600 
.520 
.920 
44-36 
16 36 
22 
1.0 
32.7 
•590 
•539 
•949 
44-5* 
+ 0.013 THE PARALLAX OF a LYRA AND 61 CYGNL 
25 
Observations of a Lyrce and Companion—Continued. 
Date. 
Clock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2Ad 
Ad 
A p 
Wt. 
Remarks. 
i Mi. 
h. m. 
h. 
III. 
O 
r. 
r. 
r. 
// 
n 
Mar. 27 
16 38 
22 
3.0 
32-7 
68.550 
59-579 
8.971 
44.62 
0.013 
3 
111. A. 
.500 
.588 
.912 
44-33 
•S31 
•594 
■937 
44-45 
•53° 
.584 
•946 
44-5° 
68.510 
59-5^> 
.920 
44.36 
r = i6k 23".6 
— 2*.I 
59.623 
68-544 
.921 
44 37 
Ad ~ 44"-4*4 
•59° 
.546 
•956 
44-54 
Ap = -(- o".oi3 
.631 
.528 
•897 
44-25 
f| = ± o".o82 
.618 
• 5*6 
.898 
44.26 
*7 * 
22 
26.0 
32,7 
•599 
•539 
.940 
44.46 
+ 0.013 
Apr. 27 
'7 39 
23 
5-7 
560 
68.564 
59-583 
8.981 
44-67 
-1- 0.012 
3 
111. H. 
•569 
•584 
•985 
44 69 
.560 
.614 
•946 
44-5° 
•57° 
•598 
.972 
44.62 
- 0-.4 
68.592 
59.621 
.971 
44.62 
T = I5k 28“.8 
59-577 
68.514 
•937 
44-45 
Ad = 44”.498 
•587 
•525 
•938 
44.46 
Ap = -j- o".OI2 
•637 
.520 
.883 
44.18 
r, = ± o".n8 
.586 
•545 
•959 
44 56 
18 11 
“3 
37-7 
55-8 
.620 
■ 5*3 
•893 
44 23 
-(- 0.012 
Apr. 27 
18 15 
23 
4*-7 
55-8 
68.529 
59.601 
8.928 
44-4° 
0.012 
2 
111. A. 
.528 
.604 
.924 
44 38 
•535 
.621 
•9*4 
44-34 
•512 
.623 
.889 
44.21 
- 0-.4 
68.510 
59.602 
.908 
44-3* 
T = i6h 1*.2 
59.620 
68.520 
.900 
44-27 
Ad = 44"-3*4 
.600 
.482 
.882 
44.18 
Ap = -|- o".oi2 
.602 
•53° 
.928 
44-4° 
r, = ± o".05i 
.604 
.520 
.916 
44-35 
18 40 
O 
6.7 
555 
.618 
•524 
.906 
44-3° 
+ 0.012 
Apr. 29 
16 49 
22 
15.6 
S2-7 
59.610 
68.560 
8.950 
44-52 
-f- 0.012 
2 
111. H. 
.608 
•55° 
•942 
44-47 
•577 
•543 
.966 
44 59 
.608 
.560 
.952 
44-52 
- 0-.5 
59.620 
68.550 
•93° 
44-42 
T = 14*1 30m.o 
68.549 
59-587 
.962 
44-57 
Ad = 44”.527 
■533 
.588 
•945 
44-49 
Ap = -|- o".oi2 
•559 
.615 
• 944 
4*-48 
r( = ± o".o6i 
•552 
.610 
.942 
44-47 
17 19 
22 
45-6 
52.0 
.564 
•569 
• 995 
44-74 
-(- 0.012 
Apr. 29 
*7 »5 
22 
516 
52.0 
59-551 
68.541 
8.990 
44-7* 
-t- 0.012 
2 
111. A. 
.6ll 
•55° 
•939 
44.46 
.617 
•554 
•937 
44-45 
.588 
.560 
.972 
44.62 
- 0-.5 
59-6I3 
68-537 
.924 
44-38 
t = I5h 6“.g 
68.568 
59.620 
•948 
44-5° 
Ad = 44"-5** 
•549 
•582 
.967 
44.60 
Ap = -(- o''.oi2 
•551 
•578 
•973 
44-63 
r 1 = ± o".o82 
■55° 
.628 
.922 
44-38 
>7 57 
a3 
a3.6 | 
510 
•563 
.639 
.924 
44-38 
-t- 0.012 
Apr. 30 
17 46 
a3 
12.8 
49.0 
68.556 
59-584 
8.972 
44.62 
-(- 0.012 
2 
111. B. 
•536 
•554 
■ 982 
44-67 
.560 
.580 
.980 
44.66 
* 
•572 
•598 | 
•974 
44 63 
- o“-3 
68.570 
59.586 
•984 
44.68 
T = I5h 2In,.6 
59-585 
68.542 
•957 
44-55 
Ad = 44".520 
.629 
•557 
.928 
44-4* 
Ap = -|- o''.OI2 
•633 
•524 
.89 c 
44-22 
n = ± o".io8 
.613 
•54* 
.928 
44-4° 
18 13 
23 
39-8 
48.2 i 
.604 
• 52* 
,qi8 
44-36 
-f- 0.012 
■ — ■■ ■ 
L 
L 
* 
' 26 
THE PARALLAX OF a LYRA5 AND 61 CYGNI. 
Observations of a Lyras, and Companion—Continued. 
Date. 
Clock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2A8 
AS 
Ap 
wt. 
Remarks. 
1881. 
h. m. 
h. m. 
0 
r. 
r. 
r. 
// 
// 
Apr. 30 
18 14 
23 40.8 
48.2 
68.554 
59.628 
8.926 
44.40 
-(- 0.012 
2 
111. A. 
.561 
•593 
.968 
44.60 
•54° 
•579 
.961 
44-57 
•55i 
.588 
•963 
44-58 
68.564 
59-6io 
•954 
44-54 
r = i5h 49m.s 
- o'". 3 
59-596 
68.550 
•954 
44-53 
AS = 44"-473 
.614 
•5°5 
.891 
44.22 
Ap z= o".OI2 
.606 
•5i7 
.911 
44-32 
= ± o".o86 
.596 
.528 
.932 
44.42 
18 41 
0 7.8 
47-4 
•585 
•542 
•957 
44-55 
-f- 0.012 
May 6 
17 56 
23 23.2 
56.2 
68.578 
59.600 
8.978 
44-65 
+ 0.012 
2 
111. A. Cloudy. 
•538 
.612 
.926 
44.40 
•552 
.591 
.961 
44-57 
•523 
.620 
.903 
44.28 
+ Om.I 
68.549 
59-58o 
•969 
44.61 
t = 15b iom.3 
59.642 
68-533 
.891 
44.22 
AS = 44"-442 
■575 
•53° 
•955 
44-54 
Ap = 4" 0,,.0I2 
.612 
•54° 
.928 
44.40 
r1 = -t o,/.ioi 
.629 
•534 
•905 
44.29 
18 27 
23 54-2 
SS-8 
.606 
•546 
.940 
44.46 
4" 0.012 
May 7 
*7 7 
22 34.1 
56.0 
68.530 
59-597 
8-933 
44-43 
-f- 0.012 
3 
111. A. 
.562 
.586 - 
.976 
44.64 
•545 
.618 
•927 
44.40 
•54i 
.602 
•939 
44.46 
68.539 
59-6i7 
.922 
44.38 
r = I4h iom.5 
om.o 
39-579 
68-544 
•965 
44-59 
AS = 44".481 
•593 
.520 
•927 
44.40 
Ap = -f- o".OI2 
.601 
•550 
•949 
44-5* 
r 1 = ± 0" .071 
.613 
•535 
.922 
44-37 
17 24 
23 5*-* 
56.0 
•598 
•572 
•974 
44-63 
-f- 0.012 
May 7 
17 28 
22 55.1 
56.0 
68.556 
59.600 
8.956 
44-54 
-(- 0.012 
3 
111. B. 
•5i5 
.620 
•895 
44.24 
•558 
.607 
•95i 
44-52 
•534 
•598 
•936 
44-44 
om.o 
68.553 
59.619 
•934 
44-44 
t = 14b 37“.4 
59.606 
68.561 
•955 
44-54 
AS = 44".464 
.616 
•542 
.926 
44.40 
Ap == -f- o".OI2 
.'602 
•554 
•952 
44-52 
= ± o".o63 
.609 
•565 
• 956 
44-54 
17 57 
55-2 
.601 
•54i 
.940 
44.46 
+ 0.012 
May 8 
16 58 
22 25.O 
59-5 
68.554 
59.600 
8-954 
44-54 
-f- 0.012 
3 
111. A. 
•521 
.630 
.891 
44.22 
•527 
•598 
• 929 
44.41 
.561 
.614 
•947 
44-5° 
68.542 
59.629 
.913 
44-33 
T = *3h 59n’-5 
— Om.I 
59-6h 
68-549 
• 938 
44.46 
AS = 44".448 
.608 
•539 
•93* 
44.42 
Ap = 4~ o".OI2 
•589 
•570 
.981 
44.67 
T\ = ± o'7.083 
.627 
•556 
•929 
44.41 
17 19 
22 46.0 
59-o 
•578 
•528 
• 95° 
44-52 
4- 0.012 
May 8 
17 22 
22 49.0 
59-o 
68.549 
59-594 
8-955 
44-54 
-f- 0.012 
3 
111. B. 
•5*6 
.619 
•897 
44 -25 
■574 
.619 
• 955 
44-54 
•547 
.618 
.929 
44.41 
— O'". I 
68.509 
59-59° 
•9*9 
44-36 
T = 14b 26™.4 
59.607 
68.552 
•945 
44-49 
AS = 44,,-5°9 
• -592 
•57° 
•978 
44-65 
Ap 4~ o".OI2 
•59° 
•572 
.982 
44.67 
rj = ± o,/.o9i 
•592 
•55° 
•958 
44-55 
*7 49 
23 16.0 
58 5 
.585 
•558 
•973 
44-63 
4- 0.012 THE PARALLAX OF a LYR/E AND 61 CYGNI. 
27 
Observations of a Lyroe and Companion—Continued. 
Date. 
Clock Tim< 
and Corr. 
s' Hour 
Angle. 
Temp. 
Micr. 
Micr. 
aA S 
AS 
Ap 
Wt. 
Remarks. 
1881. 
May 25 
h. m. 
16 16 
h. 
31 
m. 
423 
645 
r. 
68.562 
r. 
59-583 
r. 
8.979 
// 
44.66 
-j- 0.012 
3 
III. B. 
•549 
•599 
•950 
44-52 
.569 
.604 
•965 
44-59 
•S44 
•584 
.960 
44-56 
T = I2h Ilm.5 
- o",8 
68.56a 
59.600 
.962 
44-57 
AS = 44".506 
59.612 
68.542 
•93° 
44-42 
Ap = 4* o".OI2 
.614 
.540 
.926 
44-39 
T\ = ± o".o64 
.609 
.550 
.041 
44-47 
.609 
.561 
•952 
44-53 
x6 40 
32 
63 
64.0 
.620 
•539 
•9*9 
44 36 
+ 0.012 
May 35 
*6 43 
22 
9-3 
64.0 
68.544 
59-6*4 
8.930 
44.42 
-j- 0.012 
3 
111. A. 
•554 
.623 
•93* 
44-42 
•534 
.592 
.942 
44.48 
•54i 
.620 
.931 
44-37 
T = I2h SS"1.© 
- 0-.8 
68.532 
I 59-6i4 
.918 
44-36 
AS = 44"-434 
59.616 
68.570 
•954 
44-53 
Ap = -f- o".OI2 
.614 
■564 
95° 
44-52 
n = ± o".048 
.610 
•543 
•933 
44-42 
.616 
•564 
■948 
44-5° 
17 6 
22 
33.3 
635 
.612 
•522 
.910 
44-32 
-f- 0.012 
May 26 
16 25 
21 
51-3 
62.8 
68.558 
59.600 
8.958 
44-55 
-1- 0.012 
4 
111. B. 
•57° 
.58* 
•989 
44-7* 
■559 
.608 
•95* 
44-52 
•554 
.600 
•954 
44-54 
T — I2h I4m.6 
— o“.8 
68.566 
59.601 
•965 
44-59 
AS = 44,,.53° 
59-6i5 
68.539 
.924 
44-38 
Ap = + o".OI2 
.610 
•559 
•949 
44-5* 
n = ± o".o6g 
•59° 
•559 
.969 
44.61 
•599 
•552 
•953 
44-53 
16 45 
32 
”•3 
62.8 
.628 
•548 
.920 
44 36 
-)- 0.0*2 
May 26 
16 48 
22 
14 3 
62.8 
68-539 
59.618 
8.921 
44-37 
-f- 0.012 
3 
111. A. 
•538 
.609 
•929 
44 4* 
.527 
.620 
.907 
44-3<* 
.561 
.610 
.95* 
44-52 
r = I2h 37nl.o 
— om.8 
68.552 
59.623 
.929 
44-4* 
AS = 44"-44° 
59 607 
68.535 
.928 
44.40 
Ap = + o".Ol2 
•576 
■542 
.966 
44-59 
ri = ± o".058 
.606 
•532 
.926 
44.40 
.607 
.561 
.954 
44-53 
17 7 
23 
33-3 
62.5 
.605 
.546 
.94* 
44-47 
+ 0.012 
May 27 
*6 34 
22 
0.2 
67.0 
68.560 
59-6*0 
8.950 
44-52 
-f- 0.012 
3 
111. A. 
•54° 
•598 
.942 
44-47 
•554 
■599 
.955 
44-54 
.548 
.621 
.927 
44.40 
T = I2h 20m.0 
— om.g 
68-544 
59-572 
.972 
44.62 
AS = 44".466 
59-598 
68.539 
• 94* 
44-47 
Ap = + o".OI2 
•59° 
•53* 
• 94* 
44-47 
n = ± o".055 
.608 
•527 
• 9*9 
44-36 
.600 
•5*9 
• 9*9 
44-36 
16 55 
22 
21.2 
66.9 
.586 
•523 
-937 
44-45 
-j- 0.0*2 
May 27 
16 58 
22 
24.2 
66.9 
68.562 
59-58i 
8.981 
44-67 
-f- 0.0*2 
3 i 
111. B. 
•564 
•577 
.987 
44.70 
.562 
•599 
•963 
44-58 
•530 
.586 
•944 
44-48 
r = *2’’ 45™.o 
- o".9 
68.552 
59-585 
•967 
44.60 
AS = 44"-598 
59-6i7 
68.563 
•946 
44-49 
Ap = o".OI2 
.600 
.582 
.982 
44-67 
ri = ± o".o55 
•57* I 
•55° 
•979 
44-66 
.607 
•556 
•949 
44-5* 
X7 31 
.22 
47.2 
66.0 
.586 
.558 
.972 
44.62 
-f- 0.012 28 
THE PARALLAX OF a LYRyE AND 61 CYGNI. 
Observations of a Lyrce and Companion—Continued. 
Date. 
Clock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2A6 
AS 
Ap 
wt. 
Remarks. 
1881. 
h. m. 
h. 
m. 
0 
r. 
r. 
r. 
„ 
„ 
May 28 
16 32 
21 
58.2 
70. 2 
59.620 
68.552 
8.932 
44.42 
-)- 0.012 
3 
111. A. 
•599 
•551 
•952 
44-53 
596 
•533 
•937 
44-45 
.623 
•569 
•946 
44-5° 
T — 1 I2m. I 
59.623 
68.540 
•9*7 
44-35 
AS = 44"-537 
- o™.9 
68.569 
59.600 
•969 
44.61 
Ap = -J- o".OI2 
.560 
•596 
•964 
44-58 
**1 — i 0" .070 
.581 
.608 
• 973 
44.63 
•551 
•574 
•977 
44 65 
16 ,|9 
22 
15.2 
70.0 
.578 
.600 
•978 
44.65 
-f- 0.012 
May 28 
16 52 
22 
18.2 
70.0 
59.610 
68.562 
8.952 
44-52 
-|- 0.012 
3 
111. B. 
.590 
•549 
•959 
44-56 
•593 
•57* 
•978 
44-65 
.609 
•542 
•933 
44-43 
T — I2h 33m.O 
— om.9 
59-6I3 
68.570 
•957 
44-55 
AS = 44".536 
• 
68.559 
59-57* 
.988 
44.70 
Ap = -f- o".OI2 
•556 
.604 
•952 
44-52 
ri = ± 0" .061 
•554 
.618 
•936 
44-45 
•559 
.600 
• 959 
44-56 
17 11 
22 
37.2 
69.9 
•55i 
.621 
• 93° 
44.42 
-f- 0.012 
May 30 
16 29 
21 
S5-o 
73-2 
59-594 
68.560 
8.966 
44-59 
+ 0.012 
4 
111. B. 
•595 
•576 
.981 
44.67 
.605 
•57° 
.965 
44-59 
•509 
•543 
• 974 
44-63 
T = I2h 4”>,0 
— 1,n. 1 
59-578 
68.571 
• 993 
44-73 
AS = 44".578 
68.548 
59-595 
•953 
44-53 
Ap = -f- o".OI2 
■57° 
•583 
.987 
44.70 
ri = ± o".o77 
•543 
.622 
.921 
44-37 
•532 
•596 
• 936 
44.44 
16 52 
22 
18.0 
73 0 
•544 
•592 
• 952 
44-53 
-(- 0.012 
May 30 
16 55 
22 
21.0 
73° 
59.623 
68.550 
8.927 
44.40 
-J- O.OII 
3 
411. A. 
.610 
.•557 
•947 
44-5° 
,600 
•532 
•932 
44.42 
.615 
•547 
•932 
44-43 
T = 12*' 27d,.0 
— I"1. I 
59-592 
68.564 
•972 
44.62 
AS = 44"-432 
68.555 
59-634 
.921 
44-37 
Ap = -f- o".on 
•55° 
.622 
.928 
44.40 
r\ = ± o".o55 
.538 
.616 
.922 
44-38 
■5*2 
•599 
•9*3 
44-33 
17 12 
22 
38.0 
73-o 
•556 
•615 
•94* 
44-47 
-f- O.OII 
June 22 
16 36 
22 
3-9 
64.0 
68.577 
59.608 
8.969 
44.61 
-(- 0.012 
2 
111. B. 
• 570 
.625 
•945 
44-49 
• 542 
.600 
.942 
44.48 
.580 
.622 
•978 
44-65 
68.537 
59-604 
•933 
44-43 
T = IOh 4Im.O 
— 2n,.2 
59-588 
68.560 
.972 
44.62 
AS = 44"-574 
•596 
•539 
•943 
44.48 
Ap = -j- o".OI2 
• 596 
•558 
.902 
44-57 
n = ± o".o67 
.566 
■557 
•99* 
44-72 
17 2 
22 
26.9 
63-5 
• 590 
•575 
•985 
44.69 
-f- 0.012 
June 22 
*7 5 
22 
29.9 
63-S 
68.559 
59.600 
8-959 
44-56 
-f- 0.012 
2 
111. A. 
.561 
• 623 
•938 
44.46 
•567 
•595 
.972 
44.62 
.560 
.580 
.980 
44.66 
r = nh 7U\4 
68.564 
59.616 
8.948 
44-5° 
AS = * 44".572 
— 2m.2 
59.600 
68.602 
Q.002 
44-77 
Ap = + 0" ,012 
.631 
•574 
8-943 
44.48 
n = ± o".o63 
.604 
.561 
•957 
44-55 
.623 
•59* 
.968 
44.60 
17 26 
22 
50.9 
62.8 
.615 
•567 
.952 
44-52 
-|- 0.012 THE PARALLAX OF a LYR.E AND 61 CYGNI. 
29 
Observations of a Lyrce and Companion—Continued. 
Date. 
Clock Time Hour 
and Corr. Angle. 
Temp. 
Micr. 
Micr. 
2A5 
AS 
Ap 
Wt. 
Remarks. 
1881. 
h. m. 
h. 
m. 
0 
r. 
r. 
r. 
// 
// 
June 26 
»5 49 
21 
13-7 
75-4 
68.57! 
59-599 
8.972 
44.62 
+ O.OI2 
3 
111. H. 
•579 
.626 
•953 
44-53 
.582 
•634 
•948 
44-5° 
•57° 
.596 
■984 
44.68 
68-573 
59 579 
■994 
44-73 
r = 9k 38m.2 
- 2".4 
59-596 
68.565 
.969 
44.61 
Ad = 44"-639 
■584 
.560 
•976 
44 °4 
Ap = -(- o".OI2 
.591 
•564 
8-973 
44 63 
ri = ± o".056 
•583 
.586 
9.003 
44-78 
. 
16 15 
21 
39-7 
*74.8 
•57i 
•553 
8.982 
44-67 
-f- 0.012 
■ 
June 26 
16 20 
21 
44-7 
74.8 
68-533 
59.568 
8.965 
44-59 
-J- 0.012 
3 
111. A. 
.550 
•586 I 
.964 
44-58 
.560 
.613 
•947 
44-5° 
•527 
•594 
•933 
44-43 
— 2"'. 4 
68.561 
59.611 
•95° 
44-52 
T = IO*1 7“. I 
59.605 
68.549 
•944 
44.48 
• 
AS = 44"-49i 
.609 
•555 
•946 
44-5° 
Ap = -f- 0" .012 
.596 
•5*4 
.918 
44 36 
r 1 = .4; o''.050 
.586 
■54° 
•954 
44-54 
16 42 
22 
6.7 
74.0 
.618 
•548 
•93° 
44-4* 
-(- 0.012 
June 28 
16 30 
21 
54-6 
81.5 
68.590 
59-593 
8.997 
44-75 
-f- 0.012 
3 
111. H. 
•559 
•578 
.981 
44.67 
563 
•596 
•967 
44.60 
.560 
.590 
■97° 
44.61 
- 2“5 
68-543 
59.586 
•957 
44-55 
T = IO* 91".! 
59612 
68-554 
.942 
44.48 
AS — 44".6o3 
.603 
•587 
•984 
44.68 
Ap = -f" o".OI2 
.616 
.562 
•946 
44.49 
ri = 4- o''.o6o 
.610 
•564 
■954 
44-54 
16 52 
22 
16.6 
80.8 
•599 
•578 
•979 
44.66 
+ 0.012 
June 28 
16 56 f 22 
20.6 
80.8 
68.552 
59.610 
8.942 
44.48 
-)- 0.011 
2 
111. A. Images blurred. 
•534 
.606 
.928 
44.40 
•522 
•597 
•925 
44-39 
•578 
■614 
.964 
44-58 
68.554 
59-59° 
.964 
44-58 
r = iob 38m.o 
- 2-.5 
59 585 
68.556 
.971 
44.62 
AS = 44"-473 
.584 
•534 
■95° 
44-52 
Ap = -f- o".oii 
•639 
•539 
.900 
44-27 
ri = ± o".077 
.607 
•525 
.918 
44.36 
17 24 
22 
48.6 
79.2 
.620 
•574 
•954 
44 53 
-f- O.OII 
July 1 
16 25 
21 
49-4 
70.8 
68.551 
59.610 
8.941 
44-47 
-f- 0.012 
2 
111. A. Images blazing. 
•546 ' 
.631 
•9*5 
44-34 
.561 
.610 
•95* 
44-52 
•534 
.612 L 
.922 
44.38 
- 2™.7 
68.552 
59.612 
•94° 
44.46 
H 
II 
O. 
■ 
3 
59.600 
68.518 
.918 
44-36 
AS = 44"-465 
•592 
•59* 
•999 
44-76 
Ap — -f- o".OI2 
• 631 
•565 
•934 
44 43 
ri = ± o".079 
.620 
.566 
•946 
44-5° 
16 47 
22 
M.4 
69.7 
.619 
•552 
•933 
44-43 
-f- 0.012 
July 1 
17 0 
22 
24-4 
69.0 
59.604 
68.560 
8.956 
44-54 
-j- 0.012 
2 
111B. Images blazing. 
.614 
•579 
•965 
44-59 
.628 
•567 
•939 
44 46 
.606 
.580 
•974 
44-63 
59.616 
68.579 
•963 
44-58 
T = io* 28“.5 
- 2-.7 
68.591 
59-626 
•965 
44-59 
AS = 44".631 
•59i 
.608 
8.983 
44.68 
Ap — -|- o".oi2 
.628 
.580 
9.048 
45.00 
ri = ± o".ioo 
•579 
•595 
8.984 
44.68 
17 25 
22 
49-4 
68.0 
•594 
■594 | 
9.000 
44 76 
-j- 0.012 30 
THE PARALLAX OF a LYR/E AND 61 CYGNI. 
Observations of a Lyrce and Companion—Continued. 
Date. 
Clock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2A8 
AS 
A p 
Wt. 
Remarks. 
1881. 
July 2 
h. m. 
16 35 
h. m. 
21 59-3 
72.0 
r. 
68.544 
r. 
59-619 
r. 
8.925 
44-39 
-f- 0.012 
3 
111. A. 
.561 
•595 
.966 
44-59 
.560 
.612 
.948 
44-5° 
•572 
.613 
•959 
44.56 
- 2”8 
68.554 
59.610 
•944 
44.48 
T = 9h 55m-5 
59-593 
68.565 
.972 
44.62 
AS = 44,/-5°° 
•637 
•57i 
•934 
44-44 
Ap = -f- o".OI2 
.602 
.568 
.966 
44-59 
ri = ± o".o63 
.628 
•541 
•913 
44-33 
16 51 
22 15.3 
71.0 
.606 
•553 
•947 
44-5° 
-j- 0.012 
July 2 
16 54 
22 18.3 
71.0 
. 
68.560 
59-6i5 
8.945 
44.49 
-f- 0.012 
3 
111. B. 
.568 
•596 
.972 
44.62 
•550 
.627 
•923 
44-38 
•567 
•647 
.920 
44-36 
- 2"\8 
68.566 
59.601 
■965 
44-59 
t = ioh r6,n.5 
59-59° 
68.551 
8.961 
44-57 
AS = 44".560 
•567 
• 568 
9.001 
44-77 
Ap = -)- o".OI2 
•598 
.580 
8.982 
44.67 
ri = ± o".ogi 
.580 
•565 
•985 
44.69 
I7 iS 
22 39.3 
70.0 
.600 
•539 
•939 
44.46 
-(- 0.012 THE PARALLAX OF a LYRyE AND 61 CYGNI. 
31 
Observations of 6 r Cygni and 1). M. -j- 38°, 4345. 
Date. 
Clock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2A6 
Ai 
Ap 
Wt. 
Remarks. 
1880. 
h. m. 
h. m. 
O 
r. 
r. 
r. 
// 
// 
Oct. 24 
22 O 
1 1.7 
•43-o 
44 213 
84.004 
39-79* 
197.91 
-f- 0.058 
3 
.158 
84.010 
.852 
198.21 
>35 
83.971 
.836 
198.13 
.151 
84.003 
.852 
198.21 
T = 7h 59“-6 
+ 3"-3 
44 >43 
83963 
.820 
198.05 
Ai = 198”.142 
84.016 
44-*53 
.863 
198.27 
Ap = -|- o".058 
.005 
. 198 
.807 
*97-99 
rx = ± o".o82 
.007 
-*44 
.863 
198.27 
83.989 
.140 
•849 
198.20 
22 23 
1 24.7 
41.2 
84.021 
.176 
.845 
198.18 
-J- 0.058 
Oct. 25 
21 28 
O 29.7 
46.5 
83 99° 
44.196 
39-794 
197.92 
-f- 0.058 
3 
.996 
. 198 
•798 
*97 94 
.998 
.211 
-787 
197.89 
+ 3m-3 
•97* 
.202 
.769 
197.80 
T = 7h 23*.7 
83-999 
44-2*5 
•784 
197.87 
Ai = 197".870 
44.200 
83.961 
.761 
197.76 
II 
+ 
0^ 
b 
00 
.188 
83.956 
.768 
*97.79 
rt = +. o".o46 
.209 
84.012 
.803 
197.97 
.208 
83-994 
.786 
197.88 
21 51 
0 52.7 
455 
.196 
.982 
.786 
197.88 
+ 0.058 
1 Oct. 31 
21 4X 
O 4O.X 
495 
44.198 
83.961 
39-763 
*97-77 
+ 0.057 
3 
.194 
•984 
.790 
*97.90 
.201 
•972 
•77* 
197.81 
.200 
•995 
•795 
*97-93 
T = 7k 1 i”.o 
44-194 
83-972 
•778 
197.84 
A 6 =r I97".96i 
+ °m-7 
83-994 
44.176 
• .818 
198.04 
Ap = + o".057 
•99* 
.176 
.815 
198.03 
r, = ± o".o88 
83.990 
.165 
.825 
198.08 
84.029 
.186 
•843 
198.17 
22 5 
1 4.1 
48.5 
83 997 
. 180 
.817 
198.04 
+ 0.057 
Nov. 1 
21 48 
0 47.1 
48.5 
44.162 
84.002 
39-840 
198.15 
+ 0-057 
2 
.183 
83.988 
.805 
197.98 
. 196 
■978 
.782 
197.86 
.183 
•989 
.806 
197.98 
r = 7k is”.! 
+ °“7 
44.182 
83.986 
.804 
*97-97 
A6 = i97".95o 
83.985 
44 *94 
•79* 
197.91 
Ap = + o".os7 
.986 
.215 
•771 
197.81 
r, = ± o".o6g 
83.988 
.198 
.790 
197.90 
84.026 
.203 
.823 
198.07 
22 14 
* *3* 
47-5 
83.980 
. 196 
•784 
197.87 
+ 0.057 
Nov. 2 
22 3 
X 2.2 
51.0 
44 230 
83.994 
39 764 
*97-77 
-f- 0.056 
2 
•*74 
83.992 
.818 
198.04 
• *93 
84.006 
.813 
198.02 
.201 
84.032 
.831 
198.11 
T = 7k 26™.2 
+ o*".8 
44.181 
83-994 
.813 
198.02 
Ai = i98".oi5 
83-977 
44.176 
.801 
197.96 
Ap — -4- o".056 
84.005 
*39 
.866 
198.28 
rt = ± o".o92 
•973 
.183 
.790 
*97.90 
.007 
.178 
.829 
198.10 
22 29 
1 28.2 
5°-5 
83.991 
.191 
.800 
*97-95 
-f- 0.056 
Dec. 3 
• 22 29 
1 29.7 
36.2 
44-*72 
83.996 
39-824 
198.07 
+ 0-059 
3 
.191 
83-983 
•792 
197.91 
*49 
84.001 
.852 
198.21 
+ 2-3 
*43 
83 977 
•834 
198.12 
t = 5k 48">.7 
44.182 
•992 
.810 
198.00 
Ai n 198''.043 
83-993 
44.160 
•833 
198.12 
- -f o".o59 
.956 
. 160 
•796 
*97-93 
rx = ± o".o8o 
•984 
• *33 
.851 
198.21 
•957 
.l6l 
■796 
*97-93 
22 49 
1 49-7 
35-S 
.961 
. 166 
•795 
*97-93 
-f 0.059 32 
THE PARALLAX OF a LYRvE AND 61 CYGNI. 
Observations of 6i2 Cygni and 1). M. + 38°, 4345—Continued. 
Date. 
Clock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2AS 
AS 
A 9 
Wt. 
Remarks. 
1880. 
Dec. 7 
h. m. 
22 27 
h. m. 
1 28.1 
22.0 
r. 
44.174 
r. 
83.987 
r. 
39-813 
" 
198.02 
-)- 0.060 
3 
.142 
84.029 
.887 
198.39 
. 182 
•034 
.852 
198.21 
.208 
•035 
.827 
198.09 
r = 5h 30™.4 
44.207 
84.010 
•803 
197.97 
AS = 198".106 
+ 2ra.7 
83.997 
44-I7I 
.826 
198.08 
Ap = 0" .060 
84.004 
. 192 
.812 
198.01 
ri = ± o".o83 
83.996 
.179 
.817 
198.04 
84.020 
.179 
.841 
198.16 
22 45 
1 46.1 
21.5 
83.999 
. 172 
.827 
198.09 
+ 0.060 
Dec. 9 
23 4 
2 5-3 
22.7 
44.158 
84.007 
39-849 
198.20 
+ 0.061 
2 
.124 
83-971 
.847 
198.19 
•133 
84.006 
•873 
198.32 
.136 
.012 
.876 
I98-33 
II 
On 
0 
3 
+ 2m.9 
44-173 
84.000 
.827 
198.09 
AS = 198".120 
83.983 
44.189 
•794 
197.92 
Ap = -f- o".o6i 
•994 
. 182 
.812 
198.01 
n = ± o".o92 
.970 
.156 
.814 
198.02 
.981 
• 155 
.826 
198.08 
23 24 
2 25.3 
22.2 
•979 
. 162 
.817 
198.04 
-f- 0.061 
Dec. 11 
22 25 
1 26.4 
28.1 
84.022 
44.169 
39-853 
198.22 
+ °-°59 
3 
83.994 
.171 
■823 
198.07 
.994 
. 168 
.826 
198.08 
.996 
.169 
.827 
198.09 
1 
3 
b 
83.998 
44-156 
.842 
198.16 
AS = I98,,.i32 
+ 
44.162 
83.994 
.832 
198.11 
Ap = + o".o59 
. 160 
84.093 
•843 
198.17 
ri = ± o".o32 
.178 
84.016 
.838 
198.14 
.149 
83.982 
•833 
198.12 
23 31 
1 32-4 
27.2 
. 166 
84.008 
.842 
198.16 
+ 0-059 
Dec. 13 
23 16 
2 17.6 
39-5 
44.194 
83.980 
39.786 
197.88 
4* 0.060 
2 
• 
•125 
84.001 
.876 
198.33 
. 127 
83.980 
•853 
198.22 
. 169 
84.017 
.848 
198.19 
T = 5b 56“-7 
44.150 
83-974 
.824 
198.07 
AS = I98".ii4 
+ 3m-2 
83-975 
44.162 
.813 
198.02 
Ap = -|- o".o6o 
83.980 
.144 
.836 
198.13 
ri = ± o".o8s 
84.009 
. 161 
.848 
198.19 
83.980 
.160 
. 820 
198.05 
23 35 
2 36.6 
39° 
.984 
. 162 
.822 
198.06 
-)- 0.060 
Dec. 15 
23 3 
2 4-7 
44.142 
83-984 
39.842 
198.16 
+ •0-057 
2 
.124 
.990 
.866 
198.28 
. 140 
■971 
.831 
198.11 
. 140 
.981 
.841 
198.16 
T = 5h 37”-5 
44.148 
83.983 
.836 
198.13 
AS = 198".128 
+ 3m-3 
83.988 
44-179 
.809 
198.00 
> 
X' 
II 
+ 
0^ 
*0 
00 
.989 
.170 
.819 
198.05 
ri = ± o".o6i 
.980 
. 170 
.810 
198.00 
. 
83.998 
.150 
.848 
198.19 
23 25 
2 26.7 
40.3 
84.000 
.151 
.849 
198.20 
+- 0.058 
1881. 
Jan. 12 
1 17 
4 15-4 
28.5 
44-124 
. 120 
84.016 
3-993 
39.892 
•873 
198.41 
198.32 
+ 0.070 
3 
Images very good at 
times, but became 
. 160 
•963 
•803 
197-97 
poor. 
■ 134 
3-993 
•859 
198.25 
r = 5h 59m-2 
+ om.o 
44.121 
84.002 
.881 
198.36 
AS 198".322 
83-993 
44.124 
.869 
198.30 
Ap = + o".074 
84.014 
.117 
■897 
198.44 
ri = ± o".o94 * 
84.006 
.131 
■875 
I98-33 
83.984 
.099 
.885 
198.38 
I 42 
4 40.4 
28.0 
84.000 
.098 
.902 
198.46 
+ 0.077 THE PARALLAX OF LYR/E AND 61 CYGNI. 
33 
Observations of 6i2 Cyyni and I). M.+ 38°, 4345—Continued. 
Date. 
Clock Time 
and Coit. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2 A6 
Ap 
Wt. 
Remarks. 
188 
h. m. 
h. 
in. 
. 
r- 
r. 
r. 
// 
+ 0071 
Jan. 
*4 
1 23 
4 
21.5 
27.O 
44-1*7 
84.037 
39.920 
*98-55 
2 
.090 
.008 
.918 
198.54 
Very windy and tele- 
. 160 
.000 
.840 
198.15 
scope much shaken. 
. 102 
84.030 
.928 
*98.59 
44.140 
S%.q8o 
.840 
198.15 
-f o".i 
83.981 
44-°73 
.908 
198.49 
T = 5h 57m-4 
84.020 
.088 
•932 
198.61 
AS = 198".413 
83.982 
.124 
.858 
198.24 
Ap = + o".074 
83-974 
.138 
.836 
198.13 
r, - ± o".i49 
1 48 
4 
465 
25.0 
84.023 
.078 
•945 
198.68 
+ 0077 
Jan. 
*7 
1 25 
4 
23 7 
34.6 
44.100 
84.004 
39.904 
198.47 
+ 0-073 
3 
• *37 
83 977 
.840 
198.15 
.III 
84.019 
.908 
198.49 
*44 
.021 
•877 
*98-34 
44.114 
84.041 
•927 
*98-58 
T _ 5h 45»..8 
+ °“-3 
83-974 
44.070 
.904 
198.47 
AS = 198". 389 
83.980 
. IOI 
•879 
198.35 
Ap = -|- (>".076 
84.000 
.Il8 
.882 
198.36 
r, = ± o".o82 
83.979 
. Ill 
.868 
198.29 
1 46 
4 
44-7 
33-8 
83.980 
.092 
.888 
*98-39 
+ 0.079 
Jan. 
*9 
2 IX 
5 
9-7 
310 
84.045 
44.122 
39-923 
198.56 
-)- 0.091 
2 
Comp, faint after re- 
.035 
• 123 
.912 
198.51 
versal; cloudy. 
•035 
.142 
•893 
198.42 
83.992 
. IOI 
• 891 
*98 4* 
+ °"-3 
84.031 
44-*22 
.909 
198.50 
t = 6h 26™.3 
44.156 
83.961 
.805 
197.98 
AS .= 198".358 
•*3* 
.960 
• .829 
198.10 
Ap = -(- o''.ioo 
■°S7 
.910 
•853 
198.22 
r, = j- o".i39 
.046 
•974 
.928 
198.59 
2 37 
5 
35-7 
30.2 
. 122 
•989 
.867 
198.29 
-(- 0. no 
Jan. 
22 
1 48 
4 
46.8 
35-8 
83.997 
44.060 
39-937 
198.64 
-f- 0.080 
2 
84.023 
.1*7 
.906 
198.48 
83.998 
.140 
.858 
198.24 
84.050 
. 129 
.921 
198.55 
83-977 
44.086 
.891 
198.41 
r = 5h 50“.2 
+ °"-4 
44.090 
84.025 
•935 
198.62 
AS = 198".431 
.092 
83.985 
•893 
198.42 
Ap = -(- o".o85 
.O92 
.950 
.858 
198.24 
r 1 = ± o".og6 
.103 
•978 
■875 
108.33 
2 II 
5 
9.8 
35*o 
• IIO 
•995 
.885 
198.38 
-|- 0.090 
Jan. 
26 
2 4 
5 
3° 
34-5 
44.104 
84.041 
39-937 
198.64 
+■ 0.085 
3 
"3 
83.976 
.863 
198.27 
.146 
84.009 
.863 
198.27 
.136 
84.023 
.887 
198.39 
44.128 
84.013 
.885 
198.38 
T = 5h 49“-6 
+ 0-.6 
83.981 
44-095 
.886 
198.38 
AS = 198".362 
.980 
. 106 
.874 
198.32 
Ap = -f- o".092 
■984 
.138 
.846 
198.18 
r, = ± o''.o84 
83-972 
.094 
.878 
198.34 
2 25 
5 
24.0 
34-4 
84.010 
.110 
.900 
198.45 
-f- 0.100 
Jan. 
28 
2 II 
S 
IO. I 
26.5 
44.070 
83-963 
39-893 
198.42 
+ 0-094 
3 
■°95 
84.008 
•9*3 
198.52 
*35 
84.003 
.868 
198.29 
.078 
83 999 
.921 
198.55 
t = 5k 47"'-4 
+ 0 -7 
44.110 
84.014 
.904 
198.47 
Ad = 198".421 
84.017 
44.110 
.907 
198.49 
Ap = -)- o".ioi 
83 979 
.107 
.872 
198.31 
= ± 0" .066 
.990 
.IIO 
.880 
*98-35 
•993 
. 122 
.871 
198.31 
2 29 
5 
28.1 
25.2 
.990 
.o8l 
.909 
198.50 
4- 0.108 34 
THE PARALLAX OF re LYRA*: AND 61 CYGN1. 
Observations of 6r Gygni and I). M. +38°, 4345—Continued. 
Date. 
Clock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2A6 
AS 
Ap 
Wt. 
Remarks. 
1881. 
h. m. 
h. 
m. 
0 
r. 
r. 
r. 
,, 
// 
Mar. 14 
16 36 
19 
33-3 
32.8 
84.104 
44.097 
40.007 
198.98 
+ 0.073 
2 
.060 
.n8 
39.942 
198.66 
.112 
.090 
40.022 
199.06 
.041 
.091 
39-95° 
198.70 
— Im.I 
84.087 
44.077 
40.010 
199.00 
T = I7k. I9“.5 
44.080 
84.083 
40.003 
198.96 
AS = 198".829 
.080 
•037 
39-957 
198.73 
Ap = -)- o".o69 
.096 
.049 
•953 
198.71 
r, = ± o".io7 
•073 
•054 
.981 
198.85 
17 10 
20 
7-3 
32.2 
.110 
.049 
•939 
198.64 
+ 0.065 
Mar. 15 
16 26 
*9 
23.2 
38.0 
84.126 
44.072 
40.054 
199.22 
+ 0.073 
2 
.129 
.067 
40.062 
199.26 
Images blurred. 
.070 
.082 
39-988 
198.89 
•134 
047 
40.087 
199.38 
— Im.2 
84.150 
44.059 
40.091 
199.40 
r = i7h 3m.2 
44.040 
84.041 
40.001 
198.95 
AS — i99".o97 
.018 
.063 
40.045 
199.17 
Ap = -|- 0” .070 
.074 
.051 
39-977 
198.83 
r, = ± o''.i56 
•033 
.069 
40.036 
*99-*3 
16 56 
19 
53-2 
38.0 
. 102 
.061 
39-959 
198.74 
-J- 0.067 
Mar. 21 
16 54 
19 
50.; 
34-2 
84.095 
44.061 
40.034 
I99.12 
-)- 0.067 
2 
•053 
•075 
39-978 
198.84 
.072 
.095 
•977 
198.83 
.079 
.090 
•989 
198.89 
84.052 
44.114 
39-938 
198.64 
T = I7h 5m.i 
- i™.7 
44-063 
84.066 
40-003 
198.96 
AS = i98".98o 
.028 
.063 
•°3S 
199.12 
Ap = -f- o".o65 
.040 
.077 
•037 
*99-*3 
= ± o".II9 
.044 
.089 
.045 
199.17 
17 20 
20 
16.7 
33-8 
.041 
.072 
.031 
199.10 
+ 0.063 
Mar. 23 
16 53 
19 
49.6 
32.6 
84.IOI 
44.052 
40.049 
199.19 
-f- 0.067 
2 
.080 
035 
.045 
199.17 
Very unsteady. 
.064 
.029 
• 035 
199.12 
.114 
.087 
.027 
199.08 
84.092 
44.040 
.052 
199.21 
T — i6h 57“. I 
- i".8 
44.040 
84.104 
.064 
199.27 
AS = 199".256 
.030 . 
.130 
. IOO 
199.44 
Ap = + o".o65 
.049 
. 120 
.071 
199.30 
rj = ± o".o92 
.028 
.090 
.062 
199.26 
17 21 
20 
17.6 
32.2 
.004 
.118 
.114 
199-52 
-)- 0.063 
Mar. 26 
17 12 
20 
8.4 
31.0 
84.056 
44.070 
39-986 
198.88 
-f- 0.064 
2 
.010 
.082 
.928 
198.59 
.042 
.051 
.991 
198.90 
.064 
.084 
39.980 
198.85 
— 2m.O 
84.080 
44-039 
40.041 
*99-15 
T = I7k 4m-l 
44.080 
84.083 
40.003 
198.96 
AS = 198".908 
.076 
.069 
39-993 
198.91 
Ap = -f- o".o63 
.044 
.049 
40.005 
198.97 
r, = ± o".099 
.058 
.076 
40.018 
199.04 
17 40 
20 
36-4 
30.8 
.062 
•039 
39-977 
198.83 
-j- 0.062 
Mar. 27 
17 9 
20 
5-3 
32-7 
84.150 
44.050 
40.100 
199.44 
-f- 0.064 
2 
.099 
.060 
•039 
199.14 
.156 
.085 
.071 
199.30 
.142 
.048 
.094 
199.42 
— 2m.I 
84.098 
44.088 
.OIO 
199.00 
T = i6b 56“". 1 
44-059 
84.081 
.022 
199.06 
AS = 199//-*74 
.036 
.056 
.020 
199-05 
Ap - -(- o".o63 
.046 
.050 
.OO4 
198.97 
ri = 4: o".II3 
.042 
■099 
•057 
199.23 
17 35 
20 
31-3 
32.6 
.019 
.056 
•037 
*99-*3 
-f- 0.062 THE PARALLAX OF a LYRAL AND 61 CYGNI. 
35 
Observations of 61* Cygni and 1). M. -\- 38°, 4345—Continued. 
Date. 
Clock Time Hour 
and Corr. Angle. 
Temp. 
Micr. 
Micr. 
2 A6 
Ai 
* 
W, 
Remarks. 
1881. 
h. 
m. 
h. 
m. 
0 
r. 
r. 
r. 
,/ 
Apr. 
27 
18 
45 
21 
43 0 
55-5 
84.138 
44-039 
40.099 
>99-44 
+ 0.057 
3 
.126 
.046 
.080 
>99-35 
•«33 
.052 
.081 
>99-35 
T = 
l6h 27m.> 
.128 
.060 
.068 
199.29 
A <5 = 
>99"-373 
84.113 
44-°43 
.070 
199.30 
Ap = 
+ 
°"-057 
— o«4 
44 034 
84->35 
.101 
>99-45 
*•1 = 
> 
o''.056 
.070 
.164 
094 
199.42 
°54 
.120 
.066 
>99.28 
.054 
. 129 
•075 
>99.32 
*9 
2 
22 
0.0 
55-3 
.031 
.149 
.118 
>99-53 
+ 0.056 
Apr. 
19 
18 
*5 
21 
12.9 
50.8 
84.113 
44.020 
40.093 
>99-4> 
+ o-°57 
2 
.114 
.058 
.056 
199.23 
. 121 
.OOI 
. 120 
>99-54 
.069 
•037 
.032 
>99.11 
T = 
>5h 53,d-2 
— O 
"•5 
84-145 
44.041 
.104 
>99 46 
AS = 
>99"-335 
44-056 
84.099 
043 
>99.16 
Ap = 
+ 
o".o57 
.081 
>36 
055 
199.22 
*•1 = 
± 
o".>oo 
.019 
• >3* 
.112 
>99-5° 
.031 
.120 
.089 
>99-39 
18 
4° 
21 
37-9 
50.2 
.060 
.136 
.076 
>99-33 
+ 0.057 
Apr. 
3° 
18 
46 
21 
44'1 
47-o 
84.154 
44-045 
40.109 
>99-49 
+ 0.058 
2 
.159 
.038 
. 121 
>99-55 
.148 
.029 
• >>9 
>99-54 
T = 
>6h >7m.9 
.152 
.025 
• .127 
>99.58 
AS = 
>99"-466 
84.114 
44-056 
.058 
199.24 
Ap = 
+ 
o".o58 
— O 
■3 
44.062 
84.174 
. 112 
>99-5° 
>•1 = 
± 
o".072 
.041 
.149 
.108 
199.49 
.040 
•»7 
.077 
>99-33 
.024 
.140 
.116 
>99-52 
•9 
6 
22 
4> 
46.5 
•034 
. 129 
-095 
199.42 
+ 0.057 
May 
6 
18 
35 
21 
33-5 
55-8 
84 >37 
44.009 
40.128 
>99-58 
+ 0-057 
3 
.119 
.030 
.089 
>99-39 
>44 
.021 
-123 
199.56 
. Z20 
.015 
• >°5 
>99-47 
T = 
>5h 45”-3 
84.167 
44.020 
• >47 
>99.68 
A5 = 
>99"-554 
+ 0 
■.1 
44.019 
84.165 
.146 
199.67 
Ap = 
+ 
o"-°57 
.019 
>39 
. 120 
>99-54 
= 
± 
o".o6i 
.012 
.150 
• 138 
199.63 
.023 
•>33 
.IIO 
>99.49 
18 
58 
21 
56-5 
55° 
.032 
.149 
.117 
>99-53 
+ 0.057 
May 
7 
18 
4 
21 
2.4 
55 -1 
84-155 
44.007 
40.148 
>99.68 
+ 0.058 
3 
.169 
43-978 
• *9* 
199.90 
.148 
44.017 
>3> 
>99.60 
. 160 
.014 
.146 
199.67 
T = 
>5h 8“ 8 
— O 
".O 
84-145 
44.025 
. 120 
>99-54 
AS = 
>99".627 
44.021 
84.132 
.III 
>99.50 
Ap = 
+ 
o".o58 
.029 
.139 
.IIO 
199.49 
r, = 
4; 
o".o8i 
44.005 
. 129 
->24 
199.56 
43.998 
>33 
■ >35 
>99.62 
18 
*4 
21 
22.4 
54-8 
• 999 
>52 
• >53 
>99-7> 
+ 0.058 
May 
8 
>7 
57 
20 
55-3 
58.2 
84.126 
44.006 
40.120 
>99-54 
-f- 0.058 
3 
.120 
.019 
. IOI 
>99-45 
• *3° 
.040 
.090 
199.40 
T = 
>4'' 57“-8 
>44 
.008 
.136 
>99.62 
AS = 
>99"-49° 
— O 
".I 
84.144 
44.018 
.126 
>99-58 
Ap = 
+ 
o".os8 
44.042 
84.138 
.096 
199-43 
1 r* = 
± 
o".o58 
.036 
• >53 
.117 
>99-53 
•037 
.138 
.IOI 
>99-45 
.030 
•>5» 
,121 
>99-55 
18 
>7 
21 
*5-3 
58.0 
.040 
. 121 
o8l 
>99-35 
+ 0.057 36 
THE PARALLAX OF a LYR.E AND 61 CYGNI. 
Observations of 6i2 Cygni and I). M. + 38° 4345—Continued. 
Date. 
Clock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2 A<$ 
AS 
Wt. 
Remarks. 
1881. 
h. m. 
h. 
m. 
O 
r. 
r. 
r. 
„ 
„ 
May 25 
17 14 
20 
II .6 
63.0 
84-193 
44.046 
40.147 
199.68 
-f- 0.062 
3 
. 192 
.046 
. 146 
199.67 
.186 
.026 
. 160 
199-74 
.205 
.047 
.158 
199-73 
T = 
13b 7” .9 
— o™.8 
84.179 
44.012 
• 167 
199.78 
AS = 
i99"-735 
43-982 
84.180 
199-93 
Ap - 
+ 
o".o6o 
44.002 
. 140 
.138 
199.63 
r, = 
± 
o".c>79 
43-961 
.141 
. 180 
199.84 
44.014 
. 192 
.178 
199.83 
17 35 
20 
32.6' 
62.6 
44-043 
•159 
.Il6 
199.52 
4- 0.060 
May 26 
17 i5 
20 
12.6 
62.3 
84.200 
43.990 
40.210 
199.99 
4- 0.062 
2 
.181 
43.960 
.221 
200.05 
.188 
44-037 
• 151 
199.70 
.238 
44.006 
.232 
200.IO 
T = 
13b 6m.i 
84.210 
43-957 
■ 253 
200.21 
AS - 
i99"-95i 
1 
0 
3 
bo 
43.982 
84-175 
•193 
199-91 
Ap = 
+ 
o".o6o 
.988 
.176 
.188 
199.88 
r1 = 
± 
o".o99 
43-996 
• 203 
.207 
199.98 
44.019 
.199 
. 180 
199.84 
17 38 
20 
35-6 
61.7 
43.966 
■147 
. l8l 
199.85 
+ 0059 
May 27 
17 28 
20 
25-5 
6s-9 
84.187 
43.989 
40.198 
199-93 
4- 0.060 
3 
•* 
.181 
44.003 
.178 
199.83 
•195 
43.990 
.205 
199.97 
.167 
44-ois 
.152 
199.70 
T = 
13b i5m.9 
84.192 
44.001 
.191 
199.90 
AS = 
199".794 
- om.9 
43.996 
84.139 
• 143 
199.66 
Ap = 
+ 
o''.o59 
44.016 
. 167 
-151 
199.70 
r, = 
± 
o".c>9i 
44.021 
■153 
.132 
199.60 
43972 
. 172 
.200 
199.94 
17 53 
20 
50.5 
65.0 
44.011 
.165 
• 154 
199.71 
+ 0.058 
May 28 
17 17 
20 
14-5 
69.9 
44.008 
84-154 
40.146 
199.67 
-)- 0.060 
3 
44.001 
.183 
.182 
199.85 
43.982 
.196 
.214 
200.01 
43.981 
. 176 
• 195 
199.92 
T = 
l2h 58m.o 
44.022 
84.177 
• 155 
199.72 
AS = 
199T852 
- o"-9 
84.181 
43.982 
• 199 
199.94 
Ap = 
+ 
o".059 
.205 
44.010 
• 195 
199.92 
r, = 
± 
°"-°75 
•159 
44.002 
• 157 
199-73 
•173 
43-977 
. 196 
199.92 
17 36 
20 
33-5 
695 
. 104 
43 984 
. 180 
199.84 
4- 0.058 
May 30 
17 18 
20 
15-3 
73-o 
43-99° 
84.180 
40.I90 
199.89 
4- 0.060 
2 
.978 
. 192 
.214 
200.01 
•999 
.210 
.211 
200.00 
.987 
.188 
.201 
199.95 
T = 
I2h 52"’.4 
— Im.I 
43-979 
84.189 
.210 
199.99 
AS = 
i99"-955 
84.169 
43.960 
.209 
199.99 
A p = 
+ 
°"-°59 
. 160 
• 998 
. 162 
199-75 
r, - 
± 
o".io5 
. 198 
43-93° 
.268 
200.28 
.156 
44.003 
■ 153 
199.71 
17 40 
20 
37-3 
72.9 
. .178 
43 97° 
.208 
199.98 
4- 0.058 
June 26 
18 15 
21 
II.O 
72.0 
84.238 
43-973 
4°. 65 
200.27 
+ 0-057 
3 
. 180 
44-015 
.165 
199.77 
.220 
43-978 
.242 
200.15 
T = 
nh 59'«.8 
.211 
■992 
.219 
200.04 
AS = 
200". 130 
84.183 
43-949 
.234 
200.11 
Ap = 
+ 
°"-°57 
- 2“ 4 
43.969 
84.225 
.256 
200.22 
1*1 = 
± 
o".roi 
.966 
.228 
.262 
200.25 
•995 
.220 
.225 
200.07 
•954 
.199 
•245 
200.I7 
18 33 
21 
29.O 
72.0 
.978 
.240 
.262 
200.25 
4- 0.056 THE PARALLAX OF I.YR.E AND 61 CYGNI. 
37 
Observations of 6r Cygni and I). M. + 38°, 4345—Continued. 
Date. 
Clock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2 A6 
AS 
Ap 
Wt. 
Remarks. 
1881. 
h. m. 
h. 
m. 
r. 
r. 
r. 
n 
„ 
June 
28 
18 15 
21 
10.9 
79.0 
84.191 
43-959 
40.232 
200.00 
+ °-°55 
2 
Images blazing and 
.270 
44.050 
. 220 
200.04 
unsteady. 
.211 
43 923 
.288 
200.38 
.171 
43-98° 
.191 
199.90 
— 2". 5 
84.228 
44.005 
.223 
200.06 
43-930 
84.210 
.290 
200.39 
t = n» 55“.3 
AS — 200".231 
■979 
.250 
.271 
200.30 
200.49 
Ap = + o".o54 
.920 
. 229 
.309 
.958 
223 
.265 
200.27 
r 1 = ± 0 .130 
18 40 
21 
39-9 
78.8 
.928 
.317 
.289 
200.38 
+ °-°54 
July 
I 
18 7 
21 
3.7 
67.2 
84-254 
43-951 
4°-3°3 
200.46 
+ 0.056 
2 
• 250 
•95° 
.300 
200.44 
.184 
•95° 
•234 
200.11 
.206 
•97° 
.236 
200.12 
- 2-.7 
84.251 
43.961 
.290 
2OO.39 
t = nk 33".4 
43-958 
84.229 
.271 
200.30 
AS = 200".259 
43.960 
.210 
.250 
200.19 
Ap = + o".055 
44.000 
• 235 
•235 
200.12 
rt = ± o".io3 
43.960 
.250 
.290 
2OO.39 
18 28 
21 
33 7 
66.9 
•963 
.189 
.226 
200.07 
+ °-°55 
July 
2 
18 4 
20 
59-6 
69-3 
84-233 
43-946 
40.287 
200.38 
+ 0.056 
3 
•234 
.951 
.283 
200.36 
.210 
.960 
.250 
200.I9 
.205 
• 965 
.240 
200.14 
84.224 
43.968 
.256 
200.22 
T = Ilh 26m.3 
- 2".8 
43.969 
84.203 
•234 
200.11 
AS = 200".209 
.966 
.186 
.220 
2OO.O4 
Ap = + o''.o55 
• 983 
.216 
• 333 
200.11 
r, = ± o".o77 
.956 
.230 
• 274 
2OO.3I 
18 25 
21 
20.6 
68.2 
• 943 
.201 
.258 
200.23 
+ 0.055 
July 
*9 
3i 33 
O 
3»° 
68.6 
43.960 
84-251 
4O.29I 
2OO.39 
+ 0.054 
2 
Clouds after first set; 
• 933 
■375 
• 342 
200.65 
the second set com- 
•941 
.262 
• 321 
200.55 
menced at 2ih 55'". 
.928 
.280 
• 352 
2OO.7O 
— o"4 
43-944 
84.269 
• 325 
200.56 
84 218 
43-914 
• 3°4 
200.46 
r = i3h 59“.3 
.248 
.9IO 
.338 
200.63 
AS = 200".595 
.221 
• 897 
.324 
200.56 
Ap = + o".o54 
.298 
.910 
.388 
200.88 
r, — ± o".ogo 
22 12 
I 
9.0 
68.2 
.225 
■899 
.326 
2OO.57 
+ °-°54 
July 
21 
2» 35 
O 
33 0 
72.2 
84.225 
43-942 
40.283 
200.36 
+ 0-054 
2 
.268 
■953 
•315 
200.52 
.227 
.961 
.266 
200.27 
.212 
• 946 
.266 
200.27 
- om.4 
84.218 
43-944 
• 274 
200.31 
T — I3k 46“.9 
43-946 
84-243 
.297 
.301 
200.42 
Ad = 200 .386 
Ap = -f o".o54 
223 
200.44 
.946 
.201 
• 255 
200.22 
T| = ± 0 .079 
•9*7 
• 237 
.320 
200.54 
22 I 
O 
59-o 
71.9 
•933 
.248 
• 3*5 
200.51 
+ 0.054 
July 
33 
21 20 
O 
17.9 
69.0 
43.916 
84.219 
4°•3°3 
200.46 
+ 0.054 
2 
.969 
.207 
.338 
200.13 
•9*9 
• 233 
• 3M 
200.51 
.928 
• 234 
. 306 
200.47 
T = 13k 24“.0 
- o«5 
43-958 
84.232 
• 274 
2OO.3I 
AS — 200".373 
84.243 
43-957 
. 286 
2OO.37 
Ap = + o".054 
257 
.946 
•3“ 
2OO.49 
= ± o".io3 
.222 
.969 
• 253 
200.21 
.249 
.921 
.328 
200.58 
21 46 
O 
43-9 
68.7 
. 220 
.969 
.251 
200.20 
+ 0-054 38 
THE PARALLAX OF a LYR.E AND 61 CYGNI. 
Observations of 612 Cygni and D. M. -f 38°, 4345—Continued. 
Date. 
Clock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2 A5 
A6 
Ap 
Wt. 
Remarks. 
1881. 
h. m. 
h. 
m. 
0 
r. 
r. 
r. 
// 
„ 
July 24 
21 21 
O 
18.9 
7!-3 
84-233 
43-923 
40.310 
200.49 
+ o-°54 
3 
* 
•243 
•957 
.286 
200.37 
.224 
.920 
•304 
200.46 
•234 
.926 
.308 
200.48 
84-253 
43-915 
•338 
200.63 
T 
- 
X3h I9"1.! 
- o"'.5 
43-934 
84-237 
•303 
200.45 
AS 
= 
200".450 
.940 
.230 
.290 
200.39 
Ap 
= 
+ 
o".o54 
.946 
.230 
.284 
200.36 
r, 
= 
± 
<>".052 
•934 
•232 
.298 
200.43 
21 43 
O 
40.9 
71.0 
•925 
.225 
3°° 
200.44 
+ o-o54 
July 25 
21 20 
O 
17.8 
75-o 
84.249 
43-922 
40-327 
200.57 
+ 0.054 
3 
.238 
.942 
.296 
200.42 
•251 
•938 
•3!3 
200.50 
• 250 
•935 
•3i5 
200.52 
84.266 
43-953 
•3*3 
200.50 
T 
= 
I3h I4m.i 
— Om.6 
43-928 
84.197 
.269 
200.29 
AS 
= 
200".465 
•93° 
.232 
.302 
200.45 
Ap 
= 
+ 
o"-°54 
•934 
.238 
• 304 
200.46 
U 
= 
± 
o".o5i 
•955 
.261 
.306 
200.47 
21 42 
O 
39-8 
74.8 
•927 
.232 
•305 
200.47 
+ 0.054 
July 28 
21 40 
O 
37-7 
66.0 
43.906 
84.258 
40.352 
200.70 
+ 0.054 
2 
.890 
.226 
•336 
200.62 
.917 
•273 
■356 
200.72 
.902 
.227 
•325 
200.56 
43-9°7 
84.240 
•335 
200.61 
T 
= 
I3h 24m.6 
- om.7 
84.242 
43-972 
.270 
200.29 
AS 
= 
20o".530 
.230 
.925 
■ 305 
200.47 
Ap 
+ 
°"-°54 
•233 
•943 
.290 
200.39 
n 
= 
± 
o".092 
.241 
•939 
-302 
200.45 
22 7 
I 
4-7 
65.8 
■253 
•943 
• 310 
200.49 
+ 0.054 
Aug. 22 
21 I4 
O 
10.8 
71-5 
84.267 
43-895 
40.372 
200.80 
+ 0.054 
2 
.230 
.908 
.322 
200.55 
•275 
.873 
.402 
200.95 
•247 
.878 
.369 
200.78 
— I®.6 
84.246 
43-9°5 
•341 
200.64 
T 
= 
nh i8nl.o 
43.896 
84.238 
•342 
200.65 
AS 
= 
200".722 
.890 
.229 . 
-339 
200.63 
Ap 
= 
+ 
°"-054 
.864 
.225 
.361 
200.74 
D 
= 
± 
o".076 
.872 
.241 
■369 
200.78 
21 38 
O 
34-8 
71.0 
.901 
•253 
•352 
200.70 
-(- 0.054 
Aug. 23 
19 24 
22 
20.8 
73-6 
43-9“ 
84.265 
40.354 
200.71 
+ 0-054 
2 
•927 
.272 
■345 
200.66 
.900 
277 
•377 
200.82 
.908 
.261 
•353 
200.70 
— im.6 
43-887 
84.272 
■385 
200.86 
T 
= 
9h 22m.4 
84.250 
43.863 
•387 
200.87 
AS 
= 
200". 720 
•195 
■894 
-301 
200.45 
Ap 
= 
+ 
o".o54 
.261 
•913 
• 348 
200.68 
D 
= 
± 
o”.o82 
.249 
.885 
• 364 
200.76 
19 44 
22 
40.8 
72.0 
.277 
.926 
•351 
200.69 
+ 0.054 
Aug. 24 
19 32 
22 
28.8 
75-5 
84.272 
43-9IQ 
40.362 
200.75 
+ 0.054 
2 
.256 
.924 
• 332 
200.60 
.284 
•899 
• 385 
200.86 
.263 
.919 
•344 
200.66 
84.241 
43-878 
•363 
200.75 
T 
9k 27“-4 
— i,u.6 
43-923 
84.240 
• 317 
200.52 
AS 
— 
200".687 
.900 
.236 
•336 
200.62 
Ap 
rs 
+ 
o"-°54 
.904 
.262 
•358 
200.73 
7*1 
= 
o' '.071 
.899 
.230 
■331 
200.59 
19 54 
22 
50.8 
| 74-0 
.902 
.272 
•37° 
200.79 
+ 0.054 THE PARALLAX OF a LYR/R AND 61 CYGNI 
39 
Observations of 6r Cygni and 1). M. -|- 38°, 4345—Continued. 
Date. 
Clock Time 
an<l Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2A6 
AS 
Ap 
YVt. 
Remarks. 
1881. 
h. m. 
h. 
m. 
» 
r. 
r. 
r. 
// 
» 
Aug. 25 
19 11 
22 
7-8 
74.0 
43-879 
84.260 
40.381 
200.84 
+ 
0054 
2 
.928 
.264 
•336 
200.62 
■9°3 
.287 
■384 
200.86 
.920 
• 255 
•335 
200.61 
T 
= 
9h *“-S 
43.920 
84.260 
.340 
200.64 
A3 
= 
200".691 
— i".6 
84 43 
43-888 
•355 
200.71 
Ap 
= 
+ 
o".os4 
•357 
.918 
•339 
200.63 
r\ 
= 
4; 
°"-°73 
.251 
.921 
•33° 
200.59 
.241 
.911 
•330 
200.59 
19 31 
22 
27.8 
73 5 
.267 
.891 
•376 
200.82 
+ 0-054 
Aug. 26 
*9 33 
22 
29.8 
73-° 
84.297 
43-9*0 
40.387 
200.87 
+ 
0.054 
2 
•353 
•907 
346 
200.67 
.284 
.902 
.382 
200.85 
■255 
.932 
.323 
200.56 
T 
= 
9h 20™. 5 
84.290 
43 926 
•364 
200.76 
AS 
= 
200".707 
- 1 “.6 
43-9o6 
84.260 
•354 
200.71 
Ap 
= 
+ 
o".o54 
.910 
.264 
•354 
200.71 
r, 
= 
± 
o".o82 
.891 
.238 
•347 
200.67 
.948 
■255 
•307 
200.48 
>9 55 
22 
51.8 
71.9 
.889 
259 
•370 
200.79 
+ 
0054 
Sept. 5 
22 O 
0 
56-5 
84.7 
84-275 
43.920 
40-355 
200.71 
+ 
0.053 
3 
.266 
.909 
•357 
200.72 
.272 
.901 
•37* 
200.79 
T 
nk 7”.5 
.271 
•894 
•377 
200.82 
AS 
= 
200".735 
84.280 
43.916 
.364 
200.76 
Ap 
= 
+ 
°".053 
- 1-.9 
43.898 
84.251 
•353 
200.70 
r* 
= 
± 
o".°35 
.906 
.262 
•356 
200.72 
J 
.900 
.241 
•34* 
200.64 
.887 
•353 
.366 
200.77 
22 22 
1 
18.s 
84.2 
.894 
.250 
•356 
200.72 
+ 
0.053 
Sept. 6 
*9 5i 
22 
47-4 
81.8 
84.251 
43.881 
40-370 
200.79 
+ 
0053 
3 
.252 
.901 
•35* 
200.69 
.278 
.921 
•357 
200.72 
243 
.908 
•335 
200.61 
T 
81' 54l”.3 
— 2“.0 
84.268 
43-909 
•359 
200.73 
A6 
= 
200".7I2 
43-9“ 
84.250 
•339 
200.63 
Ap 
= 
+ 
o".o53 
.908 
.257 
•349 
200.68 
— 
± 
o".o42 
.892 
.262 
•370 
200.79 
.897 
.263 
.366 
200.77 
20 12 
23 
8.4 
81.2 
.911 
• 265 
•354 
200.71 
+ 
0.053 
Sept. 24 
19 22 
22 
17.8 
81.0 
84.280 
43-907 
40.373 
200.80 
+ 
0.053 
2 
.278 
■923 
••355 
200.71 
.260 
■893 
•367 
200.77 
.291 
.910 
.381 
200.84 
r 
— 
7k 12® .0 
— 2". 6 
84.308 
43-9*8 
•390 
200.89 
AS 
= 
200".788 
43 926 
84.280 
•354 
200.71 
Ap 
- 
+ 
o".053 
•934 
.296 
.362 
200.75 
u 
= 
± 
o".o39 
.920 
.293 
•373 
200.80 
.921 
• 3°2 
.381 
200.84 
*9 39 
22 
34-8 
80.0 
.919 
.286 
•367 
200.77 
+ 
0 053 
Sept. 26 
19 22 
22 
*7-7 
84.7 
84.262 
43-9*5 
40-347 
200.67 
+ 
0053 
2 
.310 
•909 
.401 
200.94 
•279 
•924 
•355 
200.71 
T 
= 
7k 4m-* 
.299 
.908 
39* 
200.89 
AS 
= 
200" .88 r 
84.294 
43-9*2 
.382 
200.85 
Ap 
+ 
°"-°53 
- 2*.7 
43.892 
84.306 
•4*4 
201.01 
r, 
± 
o”.o88 
.889 
.291 
.402 
200.95 
.882 
•3*3 
•43* 
201.09 
.911 
.281 
•37° 
200.79 
19 39 
22 
34-7 
83.8 
.898 
.292 
•394 
200.91 
+ 
0.053 40 
THE PARALLAX OF rr LYR.E AND 61 CYGNI. 
Observations of 6i‘2 Cygni and 1). M. + 38°, 4345—Continued. 
Date. 
Clock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2AS 
AS 
■V 
wt. 
Remarks. 
1881. 
h. m. 
h. 
m. 
0 
r. 
r. 
r. 
,, 
» 
Sept. 37 
21 59 
O 
54-7 
80.0 
84-273 
43-9°9 
40.364 
200.76 
+ 0053 
2 
.262 
.918 
•344 
200.66 
.265 
•925 
•340 
200.64 
.264 
■9°4 
.360 
200.74 
84.288 
43.898 
•390 
200.89 
T = 9h 40'“. 2 
- 2m. 7 
43-927 
84.292 
•365 
2OO.76 
AS = 200".826 
•893 
.308 
.415 
201.01 
Ap = + o".o53 
■893 
.276 
•383 
200.85 
rt = ± o".ogo 
•893 
• 3°° 
•407 
2OO.97 
22 23 
I 
28.7 
80.0 
.891 
.300 
.409 
200.98 
+ o-°53 
Sept. 29 
22 IO 
I 
5-6 
78.8 
43.922 
84-3I5 
40.393 
2OO.9O 
+ 0.053 
2 
.908 
.302 
•394 
2OO.9I 
• 9°5 
.294 
.389 
200.88 
• 
•3°3 
.388 
200.88 
43-9l8 
84.297 
•379 
200.83 
T = 9b 42'“.2 
- 2“.8 
84.307 
43■9°5 
.402 
2OO.95 
AS = 200".884 
.296 
.908 
.388 
200.88 
Ap = + o".053 
• 3°7 
•93° 
■377 
200.82 
D = ± o".o3i 
.306 
-9°4 
.402 
200.95 
22 32 
I 
27.6 
78.5 
• 3°5 
•925 
.380 
200.84 
+ 0-053 
Oct. 22 
22 II 
I 
9.2 
58.2 
43-885 
84.272 
40.387 
200.87 
+ 0.055 
3 
.880 
•274 
•394 
2OO.9I 
% 
.9OO 
.290 
•390 
200.89 
.882 
.282 
.400 
2OO.94 
— 0™.2 
43.884 
84.269 
■385 
200.86 
r = 8h J5m.g 
84.275 
43-870 
•405 
200.96 
AS = 200". 943 
.298 
■875 
•423 
201.05 
Ap = + °"-°55 
-293 
.862 
•431 
201.09 
r, = ± o".o53 
.271 
.863 
.408 
200.98 
22 34 
I 
32.2 
57-7 
. 2 66 
•877 
•389 
200.88 
+ 0.055 
Oct. 26 
22 29 
I 
27.2 
53-2 
43-923 
84-305 
40-382 
200.85 
■+- 0.056 
2 
Images blazing. 
.900 
•315 
•415 
201.01 
.902 
•3°7 
•405 
2OO.96 
.884 
•314 
•430 
201.09 
43•9°4 
84.292 
.388 
200.88 
t = 81' i7,n.i 
— Om.2 
* 
84.291 
43-887 
.404 
2OO.96 
AS = 200".996 
.318 
.890 
.428 
201.08 
Ap = -)- o".os6 
-294 
.884 
.410 
200.99 
r, = ± o".o72 
.289 
.891 
•398 
200.93 
22 50 
I 
48.2 
53-o 
•3*5 
.861 
•454 
201.21 
+ 0.056 
Oct. 37 
22 33 
I 
31.2 
55’9 
43-879 
84.271 
40.392 
200.90 
+ 0.056 
2 
Images blazing. 
.909 
•313 
•404 
2OO.96 
• 899 
•305 
.406 
200.97 
.9OO 
.266 
.366 
200.77 
43-9QI 
84.301 
.400 
200.94 
r = 81' 
— Om.2 
84.292 
43-853 
•439 
201.13 
AS = 2oi".oi3 
•3°4 
.878 
.426 
201.07 
Ap =r -f- o".056 
• 333 
.887 
.446 
201.17 
r, — ± o".o94 
•332 
.872 
.460 
201.24 
22 53 
I 
51-2 
55-2 
.289 
.881 
.408 
200.98 
-j- 0.056 
Nov. 4 
22 34 
I 
32.1 
4i-5 
84.311 
43-885 
40.426 
201.07 
+ 0.058 
2 
Images blurred. 
.291 
•859 
•432 
201.IO 
.296 
• 847 
■449 
201.18 
•315 
.878 
•437 
201.12 
84.286 
43.848 
.438 
201.13 
r = 711 47,n.6 
- om.3 
43.861 
84-254 
•393 
2OO.9O 
AS = 201". 035 
.898 
.287 
■389 
200.88 
Ap := + o".058 
.869 
.294 
•425 
201.06 
r 1 = ± £>".073 
■895 
.285 
•390 
200.89 
22 57 
I 
55-i 
41.0 
.865 
.281 
.416 
201.02 
+ 0.058 THE PARALLAX OF a AND 61 CYGNI. 
41 
Observations of 6i3 Cyyni and D. M. +38°, 4345—Continued. 
Date. 
Clock Time 
and Corr. 
Hour 
Angle. 
Temp. 
Micr. 
Micr. 
2A8 
AS 
Ap 
wt. 
Remarks. 
1881. 
h. m. 
h. m. 
0 
r. 
r. 
r. 
» 
// 
Nov. s 
22 50 
I 48.I 
53-5 
43-853 
84.298 
40.445 
201.16 
+ 0.056 
3 
.844 
.296 
•452 
201.20 
.869 
.297 
.428 
201.08 
.840 
.292 
•452 
201.20 
43-866 
84-3*5 
•449 
201..8 
T » 7k 57“ * 
- o". 3 
84.317 
43863 
•454 
201.21 
AS = 201".137 
.291 
.865 
.426 
201.07 
Ap = -f- o,,.056 
.298 
.849 
•449 
201..8 
r. = 4- o".048 
.289 
.875 
•4*4 
201.OI 
2 6.1 
53-° 
.291 
.863 
.428 
201.08 
-f- 0.056 
Nov. 39 
22 27 
1 24.8 
43-8 
43.862 
84.301 
40.439 
201.13 
-f- 0.058 
3 
Very faint during last 
.663 
.291 
.428 
201.08 
set; moisture on ob- 
.848 
.30* 
•453 
201.20 
jective. 
.888 
.289 
.401 
2OO.94 
43 864 
84.302 
•438 
201.13 
r = 6h 2™.5 
— om.6 
84.286 
43858 
.428 
201.08 
AS ~ 2ox,,.o87 
.272 
.838 
•434 
201.11 
Ap = + o".058 
•3*3 
.891 
.422 
201.05 
r. = ± o".o54 
.300 
.853 
•447 
201.I7 
22 51 
1 48.8 
43.6 
.309 
.900 
•409 
200.98 
-f- 0.058 
Dec. 1 
22 33 
1 30.8 
53-8 
43-834 
84.287 
40453 
201.20 
-f- 0.056 
2 
Clouds, and windy. 
.815 
• 3°8 
■493 
20I.4O 
.851 
.262 
.411 
2OO.99 
.850 
• 275 
•425 
201.06 
43.818 
84-3** 
•493 
201.40 
r = 6h 3m.i 
— o".6 
84.291 
43.818 
•473 
201.30 
AS — 201”.200 
.28l 
■ 839 
•442 
201.15 
Ap = -f- o".o56 
.267 
.811 
.456 
201.22 
r, = ± o,/.io3 
.282 
.872 
.410 
200.99 
23 2 
1 59.8 
53° 
.291 
.821 
.470 
201.29 
-f- 0.056 
Dec. 4 
22 IO 
1 7.8 
46.0 
43-844 
84.308 
40.464 
201.26 
-f- 0.058 
3 
.852 
.297 
.445 
201..6 
.850 
• 3°° 
■450 
201.19 
.868 
.3*9 
.45* 
2OI.I9 
— o".6 
43-871 
84.282 
.411 
2OO.99 
T = 5k 23“.4 
84.280 
43850 
•43° 
2OI.O9 
AS = 201".no 
.269 
•859 
.4.0 
200.99 
Ap = -|- o".o58 
.290 
.848 
•442 
201.15 
Y\ = ± o".o69 
.273 
870 
.403 
200.95 
22 29 
1 26.8 
445 
84.290 
43-852 
.438 
201.13 
-f- 0.058 
Dec. 5 
22 41 
1 38.8 
42.0 
43-842 
84.298 
40.456 
201.22 
+ 0.058 
3 
.864 
•3*4 
•450 
201.19 
.84O 
•277 
•437 
201.12 
.858 
.2 71 
■4*3 
201.00 
— o".6 
43-845 
84-303 
.458 
201.23 
t = 5k 50”.4 
84.280 
43.828 
• 452 
201.20 
AS = 201". 157 
.267 
-848 
•4*9 
201.03 
Ap = + o".os8 
.300 
•84* 
•459 
201.23 
r, = ± o".o55 
.284 
•837 
-447 
201.17 
23 O 
1 57-8 
4i-5 
84.277 
43.829 
■ 448 
201.18 
+ 0.058 
Dec. 7 
22 36 
* 33 8 
41-5 
84.302 
43-825 
40-477 
201.32 
-f- 0.058 
2 
Very windy. 
•310 
.830 
.480 
201 34 
.304 
•853 
•45* 
201.19 
.289 
•835 
•454 
201.21 
— o".6 
84.281 
43-825 
•456 
201.22 
r = 5k 40”.0 
43.827 
84.3.8 
•49* 
201.39 
AS = 201".296 
.814 
.296 
.482 
201.34 
Ap = -f- o".058 
.829 
•338 
• 509 
201.48 
r, = ± o".o64 
.836 
.302 
.466 
201.27 
23 0 
1 57-8 
41.2 
43.828 
84.280 
•452 
201.20 
+ 0.058 42 
THE PARALLAX OF a LYR/E AND£6i CYGNI. 
From these observations we have for the mean values of the probable errors of a 
single measurement in the case of a Lyrce, 
Illumination A, rx — db 0A07365, 688 measurements 
Illumination B, ± 0A07732, 590 measurements 
These values of the probable errors are practically equal, and show that but little has 
been gained by illuminating the field. Still I am inclined to think that with a good 
field illumination under proper control, one is less liable to constant errors in any given 
position of the micrometer. The companion of a Lyrce, is too faint for a' strongly 
illuminated field; but, on the other hand, the image of the large star was generally 
better than I expected to find it, and the bisections could be made in a satisfactory 
manner. The color of this star seems well suited to our 26-incli objective. 
The observations of 612 Cyyni give 
Illumination A, r, — 4- 0A08 (14, 660 measurements 
This probable error is a little greater than for the measurements of a yrce, while 
from the magnitude of the stars one would expect a different result; 612 Cyyni being 
smaller than a Lyrce and the star D. M. -f- 38°, 4345, brighter than the companion of 
a Lyrce. But the color of 612 Cyyni is such that the image of this star is generally 
not well defined by our glass; and, again, the difference of declination is so great that 
the stars were too far apart to be observed with the best results. 
The observed differences of declination need three more corrections before they 
are ready to be introduced into the equations of condition for determining the differ- 
ential annual parallax. These are 
(a) The reductions for nutation, aberration, and for precession to 1881.0; 
(/?) The reduction to the same epoch for the proper motion of the principal stars; 
(y) A reduction for the influence of changes of temperature on the screw of the 
micrometer. 
(a) Since the differences of right ascension and declination are small we may 
consider them as differentials, and by differentiating the Besselian formula for the 
reduction of a star to mean place we shall have for the reduction under this head, 
d. z/d = \ A n sin a B cos a -f- C cos a sin d -f- D sin a sin S\ . da 
-f- \ C tan go sin d -f- C sin a cos d — I) cos a cos d} . dS 
or 
d. z/d — [y sin (Gr + a) + h sin (H -f- <2) sin d\ . da 
-f {i sin d — h cos (H -f a) cos d J . dS 
The symbols in these formulae are those of the American Ephemeris, 1880, p. 258; 
and the formulae will give the reduction to the beginning of the year by using the 
auxiliary quantities of that Ephemeris. As we wish to reduce all the observations to 
1881.0, those made in 1880 need the further reduction, on account of precession, given 
by the term, 
— n sin o', da THE PARALLAX OF n LYR.fc AND 61 CYGNI. 
43 
For a Lynn this terra is -|- c^.002; and for 6iJ Cygni it is -f- o//.ooo4. The values used 
for da and dS are for a Lyras, 
_ 20". 21 44//.24 
c a ~ 206265’ ( — 206265 
and for 6r Cygni, 
<?« = +-6 40 ; d<5 = — —^ 
206265 
The reductions of the differences of declination to 1881.0 are given in the follow- 
ing tables. The dates are for Washington midnight. 
a Ljjrce. 
co 
co 
co 
co 
co 
CO 
CO 
Cl 
Cl 
Cl 
■O 
_8 
8 
8 
8 
8 
8 
8 
8 
8 
8 
8 
8 
8 
8 
8 
c 
1 
o 
o 
6 
o 
o 
o 
o 
o 
o’ 
o 
o' 
o’ 
o 
1 
o' 
~T 
o 
vO 
O 
m 
IT) 
m 
in 
m 
in 
*T 
-r 
-t- 
Cl 
•— 
ci 
Cl 
Cl 
Cl 
« 
ri 
•Q 
0) 
Uh 
Mar. 
u« 
CU 
< 
May 
June 
Jo 
Q 
_r 
CO 
Cl 
8 
O 
Cl 
Cl 
CO 
CO 
CO 
CO 
CO 
8 
8 
8 
o 
8 
8 
o 
o 
8 
8 
8 
8 
8 
8 
O 
0^ 
o 
c 
o 
o 
o 
o 
o 
o 
d 
o' 
o' 
o 
o' 
o’ 
o 
+ 
+ 
1 
i 
vO 
o 
vO 
o 
O 
vO 
in 
in 
m 
o* 
*T 
rf 
** 
ci 
Cl 
Cl 
Cl 
ci 
ra 
u 
o 
Nov. 
Dec. 
Jan. 
Feb. 
Q 
o* 
oo 
CO 
CO 
CO 
Cl 
Cl 
Cl 
Cl 
Cl 
Cl 
Cl 
Cl 
Cl 
T3 
g 
8 
8 
8 
8 
8 
8 
8 
8 
8 
8 
8 
8 
8 
8 
O 
C* 
o' 
o 
o’ 
o" 
o 
d 
o 
o 
o 
o 
o' 
o’ 
o 
o' 
o' 
+ 
+ 
o 
o 
O 
o 
o 
o 
o 
CO 
CO 
CO 
rs 
Cl 
CO 
Cl 
Cl 
*■* 
Cl 
4> 
rt 
So 
a 
IS 
J unc 
July 
Aug. 
Sept. 
Oct. 
6 
CO 
162 Cygni. 
Date. 
Red. 
Date. 
Red. 
Date. 
Red. 
1880, Oct. 20 
n 
+ 0.010 
1881, Mar. 9 
— 0.004 
1881, July 27 
— 0.006 
30 
O.OII 
19 
0.006 
Aug. 6 
0.004 
Nov. 9 
O.OI2 
29 
0.007 
16 
— 0.002 
19 
0.012 
April 8 
0.009 
26 
0.000 
29 
0.012 
18 
0.010 
Sept. 5 
+ 0.002 
Dec. 9 
O.OII 
28 
0.011 
15 
0.004 
19 
O.OII 
May 8 
0.012 
25 
0.006 
29 
0.010 
18 
0.012 
Oct. 5 
0.007 
1881, Jan. 8 
O.OO9 
28 
0.012 
15 
0.009 
18 
0.007 
June 7 
0.012 
25 
0.010 
28 
0.005 
17 
O.OII 
Nov. 4 
O.OII 
Feb. 7 
0.003 
27 
0.010 
14 
O.OII 
17 
+ 0.001 
July 7 
0.009 
24 
0.012 
27 
— 0.001 
17 
0.008 
Dec. 4 
O.OII 
Mar 9 
— 0.004 
27 
— 0.006 
14 
+ O.OII 44 
THE PARALLAX OF a LYRyE AND 61 CYGNI 
(0) For the annual proper motion of a Lyras, I adopt the value given by Profes- 
sor Boss: 
// — -f- o".2724 
On account of the orbital motion of 6i2 Cygni I adopt the value of the proper 
motion which results from Boss’s investigation, combined with 0. Struve’s value of the 
relative motion in declination. We have, therefore, for 1881.0, 
M = + 3//-2276 — o".i838 = + 3//.0438 
(y) Our 26-inch refractor was not provided with an apparatus for adjusting the 
stellar focus, but at first this was done' by holding the micrometer with the hands and 
pushing in or drawing out the tube of the micrometer until the right position was 
found, when the tube was clamped by an assistant. This method was troublesome, 
and the observer was tempted to put up with an adjustment that was not quite satis- 
factory. To assist in this adjustment, and to enable one to find the focus easily after 
the micrometer had been removed, a scale reading to Lo of an inch was engraved on 
the tube in 1876. In the spring of 1880, before beginning the observations for par- 
allax, a new arrangement for adjusting the stellar focus was attached to this telescope 
by Mr. Gardner. This consists of three light brass rings fitting closely on the tube 
of the micrometer, the middle ring moving in a dovetail between the others. From 
the middle ring a knob of the metal projects, and through this is passed a screw which 
works into a fixed part of the telescope. When the tube is unclamped a slight motion 
can be given to it by means of this screw, and the focus can be adjusted deliberately; 
and at the same time the zero of the position circle can be changed as one pleases. 
I have found that the change of the focal adjustment from summer to winter is to of 
an inch, and, contrary to what might be expected, the tube has to be pushed in during 
cold weather, and drawn out in summer. If this were simply a change of focal dis- 
tance it would produce a change of 0T0038 in the difference of declination of a Lyras 
and its companion, and a change of 0T0177 in the case of 612 Cygni. But as the total 
effect of changes of temperature on the tube of the telescope and the screw and on 
the objective cannot well be separated, it seemed better to test the effect of changes 
of temperature on the whole apparatus, at the same time that the observations for par- 
allax were being made; I have therefore measured the difference of declination of the 
two stars No. 5 and No. 12 of Professor Krueger’s catalogue of the stars in the cluster 
li Persei. This difference of declination is 18' 38"; and by means of the stars situated 
between, one can pass easily from one of these stars to the other, using the same eye- 
piece that has been used in the observations for parallax. These observations were 
made in pairs on successive days, the movable wire being placed 011 different sides of 
the fixed wire on these days for the purpose of eliminating any error in the coinci- 
dence of the wires, although this was observed on each night, and also to render the 
observations like those made for parallax. I have assumed that these stars have no 
relative proper motion, which is indicated by the meridian observations, and by my 
own measurements made after the interval of a year. In the following table are given 
the results of the observations made on sixteen niodits : 
O THE PARALLAX OF « LYR/E AND 61 CVGNI. 
45 
Date. 
R. 
Temp. 
1880. Dec. 15-16 
9.9013 
0 
37-1 F. 
18-20 
9.9066 
30.9 
1881,Jan. 14-17 
9.9240 
27.7 
July 19-21 
9.9017 
69.4 
23-24 
9.8952 
69-3 
25-28 
9.8970 
70.0 
Dec. 10-15 
9.9067 
33-4 
16-17 
9.9U7 
34-2 
rrhe values of R have been found by bringing forward the positions of Krue- 
ger’s catalogue, which give for 1880.0. 
dd — 1117//.84 
The mean value of R differs from the value adopted in the reductions, but my 
purpose being to find the coefficient of temperature, and not the absolute value of the 
revolution, I have not endeavored to correct Krueger’s JS by means of meridian 
observations. The mean value is 
R = 9>55 
Subtracting each value from the mean value, the equation of condition for the 
residuals will be of the form 
+ (£ — 50°) y + n — o 
x being the correction to the mean value of R, y the temperature coefficient, and 0 the 
reading of the Fahrenheit thermometer. The observations give the following equa- 
tions of condition : 
Equations. 
Residuals. 
X — 
12.qy 
4 
42 
O 
+ 
0.0087 
X — 
ig.ljy 
- 
11 
= 
O 
+ 
0 0057 
X — 
22. jy 
- 
185 
= 
O 
- 
0.0106 
X + 
19.4y 
+ 
38 
= 
O 
- 
0.0031 
* + 
*9-3? 
4 
103 
= 
O 
+ 
0.0032 
•* 4 
20. oy 
4- 
85 
= 
O 
4- 
0.0012 
X — 
16.6y 
- 
12 
= 
0 
+ 
0.0047 
X — 
15.8y 
— 
62 
= 
O 
— 
0.0006 
Giving to these equations equal weight, we have, by the method of least squares, 
x — — o".oooioi zbo//.ooi648 
y — — o//.ooo36o54 db o//.oooo8976 46 
THE PARALLAX OF a LYRAi AND 61 CYGNI. 
Denoting by R0 the value of a revolution for the temperature 50° F. and by R„ 
the value for the temperature 0 we have therefore, 
R, — R0 — o/,.ooo36o54 (G — 50°) 
These observations were not reduced until January, 1882, and the coefficient 
for temperature is much greater than I expected to find, since in all our previous re- 
ductions it has been assumed that this coefficient is zero. According to my plan of 
observing the determination of this coefficient was to be made while the observations for 
parallax were going on, and I think that I must accept this result, although unexpected. 
At the same time I regret that more observations were not made for the determination 
of this coefficient. Indeed it was my intention to make a set during the warm weather 
in the early part of September, 1881, but by some oversight they were omitted, and 
perhaps the assurance that this coefficient was zero made me too negligent. It is not 
probable that this coefficient has been produced by a change of declination of one of 
the stars, caused by its annual parallax, since the observations were made at a time 
when the coefficient of parallax in declination was small. As the coefficient of tem- 
perature needs further investigation, and as the stars No. 5 and No. 12, ot Krueger’s 
catalogue are convenient for this purpose, I give the formula which I have computed 
for the reduction of the difference of declination. This difference is assumed to be 
positive, and the formula gives the correction to be added to the difference of the 
mean declinations to get the apparent difference. The notation is that of Bessel, 
which has been used in the American Ephemeris since 1864. 
1880. AS — A. (8.8513J + B. (7.7416.) + C. (7.9127») + D- (6.6467.) 
1885. AS — A. (8.8525.) + B. (7.7417.) + C. (7.9130J + D. (6.6635.) 
1890. AS — A. (8.8543.) + B. (7.7418.) + C. (7-9132 J + D. (6.6797.) 
1895. J6 = A- (8.8555n) + B. (7.7420.) + C. (7-9i34») + D- (6.6938.) 
1900. AS = A. (8.8567.) + B. (7.7421.) + C. (7• 9137w) + (6.7061.) 
1905. AS — A. (8.8585.) + B. (7.7423.) + C. (7.9140.) + D. (6.7220.) 
1910. AS — A. (8.8603.) + B. (7.7425.) + C. (7.9143*) + D- (67360.) 
The quantities in parentheses are logarithms, and the letter n after the logarithms 
denotes that the factor is negative. 
The following tables give the observed differences of declination corrected for 
refraction; the reduction of this apparent difference to 1880; then Afi the reduction 
for proper motion to the same epoch; the reduction to the temperature of 50° F.; 
the sum of the reductions denoted by 2, and finally the mean values of AS. The re- 
ductions have been given separately, so that if any change in the temperature coeffi- 
cient of the micrometer screw is indicated by future observations the proper correction 
may be made easily. THE PARALLAX OF a LYR.E AND 61 CYGNI. 
47 
a Lyrce. Illumination A. 
in 
co 
r— 
o* 
o 
o 
CO 
O 
O' 
CO 
O' 
O' 
co 
CO 
o 
CO 
vO 
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o 
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Cl 
CO 
8 
in 
Cl 
Cl 
O' 
O' 
CO 
o 
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o 
vO 
co 
CO 
m 
in 
in 
O 
o 
Cl 
O’ 
co 
O'- 
CO 
vO 
co 
CO 
CO 
Cl 
in 
o 
CO 
Cl 
VO 
O 
Cl 
co 
CO 
CO 
O’ 
co 
O' 
Cl 
in 
o 
NO 
CO 
O' 
O' 
O' 
O’ 
O’ 
Cl 
< 
co 
O 
O’ 
O' 
o- 
O’ 
o 
o* 
O’ 
1* 
O 
O’ 
O' 
O' 
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O’ 
co 
O 
Cl 
o 
CO 
o 
co 
o 
Cl 
o 
CO 
T 
CO 
O’ 
CO 
o 
CO 
o 
CO 
O’ 
CO 
O’ 
CO 
o 
Cl 
Cl 
O’ 
Cl 
Cl 
Cl 
O’ 
o 
o 
o 
o 
Cl 
O’ 
o 
Cl 
Cl 
O 
rr 
o 
O’ 
O' 
o- 
O' 
O 
O* 
O’ 
o 
o* 
O’ 
O’ 
O’ 
o 
O’ 
O 
O’ 
O’ 
O’ 
o* 
O’ 
O’ 
O’ 
O' 
O’ 
O’ 
O’ 
O’ 
O’ 
O’ 
O’ 
O’ 
O’ 
O’ 
O’ 
or 
O' 
O’ 
O’ 
'S 
8 
CO 
in 
s 
in 
tn 
St 
oo 
o 
o' 
o 
in 
o 
O' 
oo 
O' 
CO 
O’ 
Cl 
O’ 
in 
O' 
O' 
Cl 
CO 
CO 
O’ 
o 
in 
co 
o 
w 
S 
<i 
6a 
ci 
d 
o 
d 
w 
H 
2 
o 
o 
d 
d 
o 
o‘ 
8 
O 
o 
o 
8 
8 
8 
o 
'S 
o' 
o 
o 
o 
o 
o" 
o 
o’ 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o’ 
o 
o’ 
o 
o 
o 
o’ 
o 
o 
o 
o 
o’ 
+ 
4- 
1 
1 
CO 
O' 
CO 
-I" 
CO 
o 
CO 
CO 
0* 
vO 
o 
O' 
Cl 
o 
Cl 
h. 
O' 
in 
Cl 
O’ 
r> 
in 
CO 
CO 
in 
vO 
o 
o 
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Cl 
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o 
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Cl 
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W) 
O* 
r^» 
O’ 
O 
OO 
in 
o 
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y\ 
o 
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o 
o 
c 
8 
o 
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d 
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o1 
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d 
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8 
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d 
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+ 
+ 
1 
1 
4 
V 
1 
! 
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m 
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in 
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oo^ 
p. 
O’ 
o 
o 
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CO 
in 
O 
n 
o 
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CO 
r*. 
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CO 
o 
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in 
O’ 
CO 
o 
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Cl 
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in 
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o 
a. 
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o 
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8 
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o 
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o 
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o 
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o 
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o 
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o 
o 
o 
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o 
o 
o’ 
o’ 
o 
o 
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+ 
4- 
1 
1 
1 
1 
1 
1 
1 
1 
8 
8 
8 
8 
8 
8 
8 
8 
8 
Cl 
8 
Cl 
8 
Cl 
8 
Cl 
8 
Cl 
8 
Cl 
8 
Cl 
8 
Cl 
8 
Cl 
8 
Cl 
8 
Cl 
8 
Cl 
8 
8 
8 
8 
8 
8 
8 
8 
s 
8 
8 
8 
8 
8 
8 
CO 
8 
CO 
8 
CO 
8 
C<) 
8 
CO 
8 
CO 
8 
o" 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
0 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o 
o’ 
o 
o 
o 
o 
o’ 
+ 
4- 
1 
1 
O' 
m 
o* 
Jt 
Cl 
CO 
O 
CO 
in 
O* 
o 
nC 
Cl 
o 
CO 
O' 
CO 
in 
o 
CO 
in 
O’ 
O’ 
O' 
CO 
O’ 
vC 
O' 
o 
CO 
o 
Cl 
CO 
o 
CO 
CO 
Cl 
O’ 
< 
Cl 
N 
** 
o 
•M 
Cl 
<N 
Cl 
- 
►* 
►* 
- 
Cl 
Cl 
Cl 
Cl 
Cl 
s 
Cl 
- 
Cl 
- 
- 
« 
S' 
o 
o‘ 
o‘ 
o 
CO 
Cl 
- 
Cl 
CO 
o . 
co 
O' 
5 
O 
4 
4 
4 
** 
o 
5 
4 
5 
O 
5 
4 
4 
o 
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5 
O’ 
4- 
4 
O 
4 
5 
5 
4 
O’ 
4 
4 
4 
4 
O 
4 
4 
O’ 
4 
4 
O’ 
4 
O' 
4 
4 
O' 
O' 
O' 
4 
O 
u-» 
o 
Cl 
CO 
ci 
CO 
CO 
o 
co 
00 
o 
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in 
o 
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in 
CO 
Cl 
O 
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S' 
- 
M 
Cl 
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- 
CO 
in 
o 
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o 
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M 
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CO >v 
-1 
line 
Jo 
be 
3 
a. 
> 
o 
u 
CO 
CO ”5 
» 
*-o 
< 
in 
o 
Z 
c 48 
THE PARALLAX OF a: LYRJE AND 61 CYGNI. 
a Lyroe. Illumination A—Continued. 
Date. 
Ad 
dd 
A 
Ad 
2 
Ado 
1881. 
" 
n 
n 
„ 
Mar. 14 
44.207 
— 0.003 
- 0.055 
— 
0.027 
— 0.085 
44.122 
15 
44.338 
0.003 
0.056 
0.018 
0.077 
44.261 
21 
44-349 
0.003 
0.061 
0.025 
O.089 
44.260 
23 
44.313 
0.003 
0.062 
0.028 
O.O93 
44.220 
26 
44.340 
0.003 
0.064 
0.030 
O.O97 
44.243 
27 
44.427 
0.003 
0.065 
- 
0.028 
O.O96 
44.331 
27 
44.326 
0.003 
0.088 
+ 
0.009 
0.082 
44.244 
29 
44.523 
0.003 
0.090 
+ 
0.002 
O.O9I 
44.432 
30 
44.485 
0.003 
0.090 
- 
0.004 
O.O97 
44.388 
May 6 
44-454 
0.002 
0.095 
+ 
0.010 
0.087 
44.367 
7 
44-493 
0.002 
0.096 
0.010 
0.088 
44.405 
8 
44.460 
0.002 
0.096 
0.015 
0.083 
44-377 
25 
44.446 
0.002 
0.109 
0.022 
O.089 
44-357 
26 
44.452 
0.002 
0. no 
0.020 
O.O92 
44.360 
27 
44.478 
0.002 
0. no 
0.027 
O.085 
44-393 
28 
44.549 
0.002 
0. in 
0.032 
0.081 
44.468 
30 
44-443 
0.002 
0.113 
0.037 
O.O78 
44.365 
June 22 
44.584 
0.001 
0 
t>5 
O 
0.021 
0. no 
44-474 
26 
44-503 
0.001 
0.133 
0.039 
0.095 
44.408 
28 
44.484 
0.001 
0.134 
0.048 
0.087 
44-397 
July 1 
44-477 
o.oor 
0.136 
0.032 
0.105 
44-372 
2 
44-512 
— o.oor 
- 0.137 
+ 
0.034 
— 0.104 
44.408 
a Lyroe. Illumination B. 
i88o. 
May 27 
44.255 
0.000 
-f 0.162 
4- 0.040 
4- 0.202 
44-457 
3i 
44.225 
0.000 
0.159 
0.035 
0.194 
44.419 
June 2 
44.346 
0.000 
0.157 
0.009 
0.166 
44.512 
22 
44.202 
+ 0.001 
0.142 
0.043 
0.186 
44-388 
23 
44.290 
0.001 
0.142 
0.048 
0.191 
44.481 
24 
44.273 
0.001 
0.141 
0.052 
0.194 
44.467 
26 
44.424 
0.001 
0.140 
0.042 
c.183 
44.607 
28 
44.241 
0.001 
0.138 
0.049 
0.188 
44.429 
30 
44-349 
0.001 
0.137 
0.041 
0.179 
44.528 
July 3 
44.254 
0.001 
0.134 
0.036 
0.171 
44.425 
26 
44.192 
0.002 
0.117 
0.052 
0.171 
44-363 
28 
44.236 
0.002 
0.116 
0.039 
0.157 
44-393 
29 
44.338 
0.002 
0.115 
0.039 
0.156 
44.494 
Aug. 12 
44.285 
0.002 
0.105 
0.035 
0.142 
44.427 
16 
44.200 
0.C02 
0.102 
■* 0.036 
0.140 
44.340 
Sept. 15 
44-197 
0.002 
0.079 
0.016 
0.097 
44.294 
16 
44.177 
0.002 
0.078 
0.024 
0.104 
44.281 
17 
44.148 
0.002 
0.078 
0.036 
0.116 
44.264 
18 
44-353 
0.002 
0.077 
0.043 
0.122 
44-475 
22 
44.229 
0.002 
0.074 
0.025 
0.101 
44.330 
Oct. 20 
44.242 
+ 0.001 
+ 0.053 
+ 0.008 
4- 0.062 
44.304 THE PARALLAX OF a LYR.E AND 61 CYGNI. 
49 
a Lyrce. Illumination B—Continued. 
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Oct. 
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z 
Dec. 
1881 
Feb. 
Mar. 
a, 
< 
May 
O 
C 
3 
July 50 
THE PARALLAX OF a AND 6r CYGNI. 
612 Cygni. 
1 
Date. 
Ad 
d& 
A n 
Ad 
2 
Ad 
1880. 
II 
» 
n 
„ 
„ 
Oct. 24 
198.200 
+ 
0.010 
+ 
O.560 
- 
O.057 
+ 
0.513 
198.713 
25 
197.928 
0.010 
0-552 
0.029 
0-533 
198.461 
3i 
198.018 
O.OII 
0.502 
0.007 
0.506 
198.524 
Nov. 1 
198.007 
O.OII 
0.493 
- 
0.014 
0.490 
198.497 
2 
198.071 
0.011 
O.485 
+ 
0.006 
0.502 
198.573 
Dec. 3 
198.102 
0.012 
0.227 
- 
O. 102 
0.137 
198.239 
7 
198.166 
O.OII 
O.I94 
0.204 
+ 
0.001 
198.167 
9 
198.181 
O.OII 
0.177 
O.I99 
- 
O.OII 
T98.170 
11 
198.191 
O.OII 
O. l6l 
O. l6l 
+ 
O.OII 
198.202 
13 
198.174 
O.OII 
O.I44 
*0.078 
0.077 
198.251 
15 
198.186 
O.OII 
+ 
0.127 
0.068 
+ 
0.070 
198.256 
1881. 
Jan. 12 
198.396 
0.008 
- 
O. 106 
0-157 
- 
0.255 
198.141 
14 
198.487 
0.008 
0.123 
0.173 
0.288 
198.199 
17 
198.465 
0.007 
O. I48 
O. II4 
0.255 
198.210 
198.458 
0.007 
O.165 
O. I40 
0.298 
198.160 
22 
198.516 
0.006 
O. I90 
0.105 
0.289 
198.227 
26 
198.454 
0.005 
0.223 
O. II4 
0.332 
198.122 
28 
198.522 
+ 
0.005 
O.24O 
O.I74 
0.409 
198.113 
Mar. 14 
198.898 
— 
0.005 
O.618 
0.126 
0.749 
198.149 
!5 
199.167 
0.005 
0.627 
O.087 
0.719 
198.448 
21 
199.045 
0.006 
O.677 
O.II5 
0.798 
198.247 
23 
199.321 
0.006 
O.694 
O. 127 
0.827 
198.494 
26 
198.971 
0.007 
O.719 
O. 138 
0.864 
198.107 
27 
199.237 
0.007 
0.727 
— 
0.125 
0.859 
198.378 
Apr. 27 
199.430 
O.OII 
O.985 
\ + 
O.O39 
0.957 
198.473 
29 
199.392 
O.OII 
I .OOI 
+ 
0.004 
1.008 
198.384 
30 
199.524 
0.011 
I .OIO 
— 
0.023 
1.044 
198.480 
May 6 
199.611 
0.012 
1.060 
+ 
O.O39 
1-033 
198.578 
7 
199.685 
0.012 
1.068 
O.O36 
1.044 
198.641 
8 
199.548 
0.012 
I.O76 
O.O58 
1.030 
198.518 
25 
199-795 - 
0.012 
I.217 
O.O92 
I-I37 
198.658 
26 
200.01I 
0.012 
1.225 
O.087 
1.150 
198.861 
27 
I99-853 
0.012 
1-234 
O. Ill 
1-135 
198.718 
28 
I99.911 
0.012 
1.242 
O. I42 
1.112 
198.799 
30 
200.014 
0.012 
1-259 
O. 166 
1.105 
198.909 
June 26 
200.I87 
0.010 
1.484 
0.159 
1-335 
198.852 
28 
200.285 
0.010 
1.500 
0.208 
1.302 
198.983 
July 1 
2OO.3I4 
0.010 
t-525 
O.I23 
1.412 
198.902 
2 
2OO.264 
O.OOg 
1-533 
0.135 
1.407 
198.857 
19 
2OO.649 
0.008 
1.676 
0-133 
I-55I 
199.098 
21 
200.440 
0.007 
1.692 
O.I59 
1.540 
198.900 
23 
200.427 
0.007 
1.709 
O.I36 
1.580 
198.847 
24 
200.5O4 
0.006 
I-7I7 
0.152 
1 • 571 
198.933 
25 
2OO.5I9 
0.006 
I-725 
0.180 
I-55I 
198.968 j 
28 
2OO.584 
— 
0.006 
— 
1.75i 
+ 
0.II5 
— 
1.642 
198.942 THE PARALLAX OF a LYRyE AND 61 CYGNI. 
51 
612 Cygni—Continued. 
Date. 
A<* 
* 
A, 
A » 
S 
Ad 
1881. 
» 
" 
tt 
Aug. 22 
200.776 
— 
0.001 
- 1.958 
+ 
0.154 
- 1.805 
198.971 
23 
200.774 
- 
0.001 
1.966 
0.164 
1.803 
19S.971 
24 
200.741 
0.000 
1.974 
0.179 
t-795 
198 946 
25 
200.745 
0.000 
1.982 
0.171 
1.811 
198.934 
26 
200.761 
0.000 
1.991 
0.162 
1.829 
198.932 
Sept. 5 
200.788 
+ 
0.002 
2.075 
0.248 
1.825 
198.963 
6 
200.765 
0.002 
2.082 
0.227 
1.853 
198.912 
24 
200.84X 
0.006 
2.232 
0. 220 
2.006 
198.835 
26 
2OO.934 
0.006 
2.248 
O.247 
1.995 
198.939 
27 
2OO.879 
0.006 
2.258 
0.216 
2.036 
198.843 
29 
200.937 
0.006 
2.274 
0.206 
2.062 
198.875 
Oct. 22 
2OO.998 
0.010 
2.465 
O.O58 
2-397 
198.601 
26 
201.052 
0.010 
2.499 
0.022 
2.467 
198.585 
27 
201.069 
0.010 
2.507 
+ 
O.O4O 
2.457 
198.612 
Nov. 4 
201.O93 
O.OII 
2.573 
- 
O.063 
2.625 
198.468 
5 
201.I93 
O.OII 
2.582 
+ 
0.023 
2.548 
198.645 
29 
201.I45 
0.012 
2.781 
- 
O.O45 
2.814 
198.331 
Dec. 1 
201.256 
O.OII 
2.798 
+ 
0.025 
2.762 
198.496 
4 
201.l68 
O.OII 
2.822 
- 
0.035 
2.846 
198.322 
5 
201.215 
O.OII 
2.831 
0.060 
2.880 
198.335 
7 
201.354 
4- 
0.011 
- 2.854 
- 
0.062 
- 2.905 
198.449 
Iii the case of a Lyrce the reduced values of JS show that the adopted annual 
proper motion of this star represents the measurements very well. On the other 
hand, the observations of 6i2 Cygni indicate a small correction to the value of this 
proper motion, but this will be cared for by the equations of condition. These equa- 
tions are of the form, 
x + % + cz + du + n — o 
In this equation x is the correction to an assumed value of JS; y is the correction to 
the value of the annual proper motion which has been used in reducing the JS of the 
two stars to the epoch 1881.0; z is the difference of the constants of aberration, which 
have been assumed to be the same for both stars; and u is the annual relative parallax 
of the stars. The coefficients have the following values: 
h — 1881.0 — r 
O 1 
c—1(9.94578) sin (O + 264 11.1); a Lyrce 
c — {9.92225) sin (O + 238 15.2); 6r Cygni 
d— (9 945 78) R cos (O + 264 11.1); a Lyrce 
d— (9.92225) R cos (0 + 238 15.2); 61'- Cygni 
where O Is the longitude of the sun, and R its radius vector. The independent term 
n is the difference between an assumed value of JS and the observed value. These 
values have been assumed as follows: 
for a Lyrce; JS0 — 44".200: and JS0 — 44".300 
for 612 Cygni; 198".560 52 
THE PARALLAX OF a LYR.E AND 61 CYGNI, 
In nearly every case the weight unity has been assigned to the observation, but 
for a few nights, where the notes indicate unusual disturbance of the images, the 
weight has been reduced to one-lialf. The following are the equations of condition: 
a Lyrce. Illumination A. 
No. 
Date. 
Equations. 
Residuals. 
Wt. 
i 
1880. 
May 24 
x 4- 0.60239/ 
— 0.46082 
4- 0.7628w 
— 0.135 = 0 
4- 0.005 
1 
2 
25 
+ 0.5996 
— 0.4481 
4- 0.7707 
— 0.217 
- 0.075 
3 
26 
4- 0.5969 
- 0.4354 
4- 0.7783 
— 0.204 
— 0.060 
4 
27 
+ 0.5941 
— 0.4225 
4- 0.7857 
1 
0 
CO 
0 
- 0.035 
5 
3i 
+ 0.5832 
- 0.3703 
4- 0.8128 
— 0.207 
— 0.056 
6 
June 
2 
+ 0.5777 
— 0.3430 
4- 0.8253 
- 0.139 
4- 0.014 
7 
17 
4- 0.5367 
— 0.1316 
4- 0.8870 
— 0.049 
4- 0*120 
8 
18 
4- 0.5340 
— 0.1170 
4- 0.8891 
- 0.137 
4- 0.032 
9 
21 
4- 0.5258 
- 0.0733 
4- 0.8941 
— 0.163 
4- 0.008 
IO 
22 
+ 0.5230 
- 0.0583 
f 0.8953 
— 0.168 
4- 0.004 
ii 
23 
4- 0.5204 
— 0.0441 
4- 018961 
— 0.204 
— 0.031 
12 
27 
+ 0.5096 
4- 0.0135 
4- 0.8973 
— 0.191 
— 0.017 
13 
28 
+ 0.5068 
4- 0.0288 
4- 0.8969 
— 0.132 
4- 0.043 
14 
30 
4- 0.5012 
4- 0.0582 
4- 0.8955 
— 0.200 
— 0.025 
l5 
July 
3 
4- 0.4930 
4- 0.1024 
4- 0.8914 
— 0.125 
4- 0.051 
16 
27 
4- 0.4275 
4- 0.4346 
4- 0.7799 
— 0.072 
4- 0.095 
17 
28 
4- 0.4248 
4- 0.4473 
4- 0.7724 
— 0.099 
4- 0.067 
18 
30 
4- 0.4193 
4- 0.4723 
4- 0.7567 
— 0.103 
4- 0.062 
19 
3i 
4- 0.4166 
4- 0.4849 
4- 0.7484 
— 0.149 
4- 0.015 
20 
Aug. 
12 
4- 0.3838 
4- 0.6220 
4- 0.6343 
— 0.067 
4- 0.083 
21 
15 
4- 0.3755 
4- 0.6530 
4- 0.6010 
- 0.133 
+ 0.013 
22 
16 
+ 0.3729 
4- 0.6623 
4- 0.5904 
— 0.151 
— 0.007 
23 
Sept. 
14 
4- 0.2934 
4- 0.8592 
4- 0.2032 
- 0.155 
— 0.063 
24 
15 
4- 0.2906 
4- 0.8625 
4- 0.1885 
- 0.144 
- 0.055 
25 
17 
4- 0.2851 
4- 0.8684 
4- 0.1586 
— 0.142 
- 0.057 
26 
18 
4- 0.2825 
4- 0.8708 
4- 0.1444 
— 0.198 
— 0.115 
» 
27 
22 
4- 0.2715 
4- 0.8786 
4- 0.0842 
- 0.163 
— 0.089 
28 
Oct. 
20 
4- 0.1951 
4- 0.8176 
— 0.3308 
— 0.013 
0.000 
29 
24 
4- 0.1841 
4- 0.7926 
— 0.3860 
— 0.058 
- 0.054 
30 
25 
CO 
d 
4- 
4- 0.7856 
— 0.3996 
— 0.023 
— 0.021 
3i 
3i 
4- 0.1650 
4- 0.7394 
— 0.4782 
- 0.075 
— 0.085 
32 
Nov. 
1 
4- 0.1622 
4- 0.7308 
— 0.4909 
4- 0.014 
4- 0.002 
33 
2 
4- 0.1595 
4- 0.7219 
- 0.5034 
— 0.012 
— 0.028 
34 
Dec. 
3 
4- 0.0747 
4- 0.3536 
— 0.7968 
4- 0.084 
4- 0.022 
35 
7 
4- 0.0638 
4- 0.2954 
— 0.8191 
0.080 
4- 0.014 
36 
9 
4- 0.0583 
4- 0.2656 
— 0.8286 
4- 0.087 
4- 0.019 
37 
11 
4- 0.0528 
4- 0.2356 
— 0.8372 
4- 0.069 
0.000 
38 
13 
4- 0.0474 
4- 0.2052 
— 0.8448 
4- 0.182 
4- 0.111 
39 
15 
4- 0.0419 
4- 0.1746 
- 0.8513 
4- 0.166 
4- 0.094 
40 
16 
4- 0.0391 
4- 0.1592 
— 0.8541 
4- 0.151 
4- 0.078 
4i 
18 
4- 0.0337 
4- 0.1283 
— 0.8590 
4- 0.148 
4- 0.074 
42 
1881 
Feb. 
10 
- 0.1157 
— 0.6468 
- 0.5930 
— 0.060 
— 0.099 
43 
13 
— 0.1239 
— 0.6776 
— 0.5588 
4- 0.002 
— 0.031 THE PARALLAX OF a AND 61 CYGNI. 
53 
a Lyras. Illumination A—Continued. 
No. Date. 
Equations. 
Residuals. 
Wt. 
1881. 
11 
If 
44 Feb. 
14 
x — 0.1267? 
— 
0.68752: 
— 0.5469M 
-f- O.IOI = 0 
4- 0.069 
1 
45 
16 
— 0.1321 
- 
0.7065 
— 0.5231 
+ 0.026 
— 0.003 
46 
19 
— 0.1403 
- 
0.7333 
— 0.4860 
- 0.034 
— 0.056 
47 
21 
- 0.1457 
- 
0.7501 
— 0.4605 
— 0.027 
- 0.045 
48 Mar. 
14 
— 0.2031 
- 
0.8669 
— 0.1651 
+ 0.078 
4- 0.106 
49 
15 
— 0.2059 
- 
0.8696 
— 0.1503 
— 0.061 
— 0.030 
5° 
2r 
— 0.2223 
- 
0.8806 
— 0.0599 
— 0.060 
— 0.01^ 
51 1 
23 
— 0.2278 
- 
0.8821 
— 0.0294 
— 0.020 
+ 0.028 
52 
26 
— 0.2360 
- 
0.8825 
+ 0.0163 
— O.O43 
+ 0.015 
53 
27 
— 0.2387 
- 
0.8821 
+ 0.0314 
- O.I3I 
— 0.071 
54 Apr. 
27 
— 0.3236 
- 
0.7454 
+ 0.4763 
— 0.044 
4- 0.092 
55 ' 
29 
— 0.3290 
- 
0.7291 
+ 0.5014 
— 0.232 
— 0.091 
56 
30 
- 0.3317 
- 
0.7205 
+ 0.5141 
1 
O 
f 
CO 
— 0.045 
57 May 
6 
— 0.3481 
- 
0.6654 
+ 0.5855 
— 0.167 
— O.OII 
58 
7 
- 0.3507 
- 
0.6560 
+ 0.5964 
— 0.205 
- 0.047 
59 
8 
- 0.3534 
- 
0.6015 
+ 0.6525 
1 
0 
vj 
— 0.009 
60 
25 
- 0.3998 
- 
0.4511 
+ 0.7689 
- 0.157 
4- 0.034 
61 
26 
— 0.4026 
- 
0.4384 
+ 0.7765 
— 0.160 
4- 0.032 
62 
27 
— 0.4052 
- 
0.4257 
+ 0.7839 
- 0.193 
+ 0.001 
63 
28 
— 0.4080 
- 
0.4127 
+ 0.7911 
— 0.268 
- 0.073 
64 
30 
- 0.4135 
- 
0.3862 
+ 0.8050 
— 0.165 
-L- 0.033 
65 June 
22 
- 0.4763 
- 
0.0620 
+ 0.8950 
- 0.274 
- 0.053 
66 
26 
— 0.4872 
- 
0.0039 
+ 0.8974 
• — 0.208 
4- 0.015 
67 
28 
— 0.4926 
+ 
O 
b 
to 
cn 
CO 
+ 0.8970 
- 0.197 
+ 0.027 
68 July 
1 
— 0.5008 
+ 
0.0693 
+ 0.8947 
— 0.172 
+ 0.052 
69 
2 
— 0.5036 
+ 
0.0840 
+ 0.8933 
— 0.208 
4- 0.016 
a Lyrce. Illumination B. 
I 
1880. 
May 27 
* 4- 
0.5942^ 
0.42292 
+ 
0.7854// 
0.157 = 0 
— 0.006 
1 
2 
31 
4- 
0.5833 
- 
0.3704 
+ 
0.8127 
- 
0.119 
4- 0.038 
3 
June 
2 
+ 
0.5778 
- 
0.3434 
4- 
0.8251 
- 
0.212 
- 0.053 
4 
22 
4- 
0.5230 
— 
0.0586 
4- 
0.8953 
- 
0.088 
+ 0.091 
5 
23 
+ 
0.5204 
- 
0.0443 
+ 
0.8961 
- 
0.181 
— 0.008 
6 
24 
+ 
0.5177 
- 
0.0294 
+ 
0.8968 
- 
0.167 
+ 0.006 
7 
26 
+ 
0.5122 
- 
0.0004 
+ 
0.8974 
- 
0.307 
- 0.134 
8 
28 
+ 
0.5067 
4- 
0.0291 
+ 
0.8969 
- 
0.129 
+ 0.044 
9 
30 
+ 
0.5012 
4- 
0.0586 
+ 
0.8955 
- 
0.228 
— 0.056 
• 
IO 
July 
3 
+ 
0.4931 
+ 
0.1021 
+ 
0.8915 
- 
0.125 
+ 0.046 
11 
26 
4- 
0.4303 
+ 
0.4214 
+ 
0.7874 
- 
0.063 
+ 0.086 
12 
28 
+ 
0.4248 
+ 
o.4t7i 
+ 
0.7725 
- 
0.093 
+ 0.052 
>3 
29 
+ 
0.4220 
+ 
0.4599 
+ 
0.7646 
- 
0.194 
— 0.050 
«4 
Aug. 
12 
+ 
0.3838 
4- 
0.6230 
+ 
0.6333 
— 
0.127 
— 0.011 
15 
16 
4- 
0.3729 
+ 
0.6625 
+ 
0.5902 
— 
0.040 
— 0.067 
16 
Sept. 
15 
+ 
0.2906 
+ 
0.8625 
+ 
0.1882 
+ 
0.006 
+ 0.030 
*7 
16 
+ 
0.2879 
+ 
0.8656 
+ 
0.1733 
+ 
0.019 
4- 0.040 
. 54 
THE PARALLAX OF a AND 61 CYGNI. 
a Lyrce. Illumination B—Continued. 
No. 
Date. 
Equations. 
Residuals. Wt. 
1880. 
n 
n 
18 
Sept. 
17 
x 4- 0.2850^ 
4- 
0.86850 
4- 0.1581a 
4- 
O.O36 = O 
4 0.038 i 
19 
18 
4 0.2825 
4- 
0.8709 
4- 0.1441 
- 
0.175 
— 0.160 
20 
22 
4 0.2715 
4- 
0.8787 
4- 0.0839 
- 
O.O3O 
- 0.027 
21 
Oct. 
20 
4 0.1950 
4- 
0.8175 
— 0.3311 
- 
O.OO4 
— 0.084 ' • 
22 
24 
4- 0.1841 
4- 
0.7924 
— 0.3863 
4 
0.060 
— 0.030 
23 
25 
4- 0.1814 
+ 
0.7355 
- 0.3998 
4- 
0.023 
— 0.070 
24 
3i 
4 0.1650 
4- 
0.7392 
- 0.4784 
4 
0.073 
- 0.035 : • 
25 
Nov. 
1 
4- 0.1622 
4- 
0.7307 
— 0.4910 
4- 
O. 120 
4- a.009 ; . 
26 
Dec. 
3 
4- 0.0747 
4- 
0.3534 
— 0.7969 
4 
0.173 
4- 0.006 
,7 
9 
4- 0.0582 
4- 
0.2654 
— 0.8287 
4- 
O.263 
4- 0.091 
28 
11 
4- 0.0528 
+ 
0.2355 
- 0.8373 
4- 
O.269 
4- 0.096 
29 
13 
4- 0.0473 
+ 
0.2051 
— 0.8448 
4- 
O. 167 
— 0.007 
30 
16 
4- 0.0390 
4 
0.1590 
- 0.8541 
4- 
0.154 
— 0.021 
3i 
18 
4- 0.0336 
4- 
0.1280 
— 0.8590 
4- 
O.283 
4- 0.107 
32 
22 
4- 0.0227 
4- 
0.0659 
— 0.8656 
+ 
O.254 
4- 0.078 
1881. 
33 
Feb. 
6 
- 0.1047 
— 
0.6029 
— 0.6361 
4- 
O.O42 
— 0.052 4 
34 
12 
— 0.1212 
- 
0.6675 
- 0.5704 
- 
0.031 
— 0.132 
35 
14 
— 0.1267 
- 
0.6873 
- 0.5472 
4- 
O. Il8 
4- 0.022 
36 
l6 
— 0.1320 
- 
0.7063 
- 0.5233 
4- 
0.080 
— 0.010 
37 
19 
— 0.1402 
- 
o.733i 
— 0.4862 
4- 
0.068 
- 0.014 
38 
21 
- 0.1457 
- 
0.7496 
— 0.4611 
4- 
O.O74 
— 0.003 
39 
Mar. 
14 
— 0.2031 
- 
0.8668 
— 0.T654 
- 
0.017 
— 0.029 
40 
15 
— 0.2059 
- 
0.8696 
- 0.1505 
4- 
O.OO3 
— 0.005 
4i 
21 
— 0.2222 
- 
0.8806 
— 0.0602 
- 
0.066 
- O.055 ! . 
42 
23 
— 0.227S 
- 
0.8821 
— 0.0296 
4- 
O.O37 
4 0.055 . 
43 
26 
— 0.2360 
- 
0.8825 
4- 0.0160 
- 
O.O79 
- 0.051 
44 
27 
— 0.2386 
- 
0.8821 
4- 0.0311 
- 
0.003 
4- 0.028 
45 
April 
27 
- 0.3235 
- 
0.7455 
4- 0.4760 
- 
O. 128 
— 0.003 
46 
29 
— 0.3289 
- 
0.7295 
4- 0.5009 
- 
0.150 
— 0.020 
47 
30 
- 0.3317 
- 
0.7206 
+ 0.5139 
- 
0.137 
— 0.004 
48 
May 
7 
— 0.3508 
- 
0.6558 
4- 0.5966 
- 
O.087 
4 0.063 
49 
8 
- 0.3535 
- 
0.6456 
4- 0.6077 
- 
0.137 
4 0.015 
50 
25 
— 0.3997 
- 
0.45M 
4- 0.7687 
- 
0.130 
4 0.055 
51 
26 
— 0.4025 
- 
0.4386 
+ 0.7764 
- 
O.I5I 
4 0.036 
52 
27 
- 0.4053 
- 
0.4254 
4- 0.7841 
- 
0.224 
— 0.035 1 • 
53 
28 
— 0.4081 
- 
0.4125 
4- 0.7912 
- 
O.167 
4 0.023 1 . 
54 
30 
— 0.4134 
- 
0.3864 
4- 0.8049 
- 
0.212 
- 0.019 
55 
June 
22 
- 0.4763 
- 
0.0623 
4- 0.8950 
- 
0.177 
4 0.033 ! • 
56 
26 
- 0.4871 
- 
0.0048 
4- 0.8973 
- 
0.257 
— 0.046 
57 
28 
— 0.4926 
4- 
0.0255 
4- 0.8970 
- 
O.23O 
— 0.020 \ . 
58 
July 
1 
— 0.5008 
4- 
0.0697 
4- 0.8946 
- 
O.256 
— 0.046 * . 
59 
2 
— 0.5036 
4- 
0.0842 
4- 0.8933 
— 
O.167 
4- 0.042 THE PARALLAX OF a LYR.E AND 61 CYGNI. 
55 
612 Qygni. 
No. 
Date. 
Equations. 
Residuals. 
Wt. 
1880. 
11 
II 
i 
Oct. 
24 
x 4 o.i83qy 
4- 0.8361Z 
— 0.0040M 
— 
0.153 = 0 
— 0.149 
1 
2 
25 
4- 0.1812 
+ 0.8359 
— 0.0181 
+ 
0.099 
4- 0.097 
3 
31 
4- 0.1648 
4- 0.8294 
— 0.1045 
4- 
0.036 
— 0.007 
4 
Nov. 
1 
4 0.1621 
+ 0.S274 
— 0.1189 
+ 
0.063 
4- 0.013 
5 
2 
+ 0.1593 
4- O.8252 
- 0.1333 
- 
0.013 
— 0.069 
6 
Dec. 
3 
4- 0.0746 
4- O.6359 
- 0.5349 
4 
0.321 
4 0.064 
7 
7 
4- 0.0638 
+ O.5960 
- 0.5774 
4 
O 
<-0 
O 
4- 0.114 
8 
9 
4 0.0582 
4 O.5746 
— 0.5980 
4 
0.390 
4 0.099 
9 
11 
+ 0.0528 
+ O.5530 
— 0.6172 
+ 
0.358 
4 0.057 
IO 
13 
4- 0.0473 
4 O.530O 
— 0.6363 
4- 
0.309 
— 0.003 
11 
1881 
15 
4- 0.0418 
+ 0.5069 
— 0.6542 
4- 
0 
u 
0 
4- 
— 0.017 
12 
Jan. 
12 
- 0.0349 
+ O.1275 
— 0.8127 
4 
0.419 
— 0.003 
13 
M 
— 0.0404 
4 O.O981 
— 0.8168 
+ 
0.361 
— 0.046 
i 
M 
17 
— 0.0486 
+ O.0539 
— 0.8209 
+ 
0.350 
— 0.081 
15 
19 
— 0.0542 
4- 0.0237 
— 0.8225 
+ 
0.390 
— 0.031 
i 
16 
22 
— 0.0623 
— 0.0204 
— 0.8229 
4- 
0.333 
— 0.104 
17 
26 
— 0.0732 
— 0.0796 
— 0.8197 
4 
0.438 
— 0.002 
18 
28 
— 0.0787 
— 0.1090 
— 0.8167 
+ 
0.447 
4- 0.002 
>9 
Mar. 
14 
— 0.2032 
— 0.6700 
- 0.4977 
+ 
0.411 
4 0.088 
• 20 
15 
— 0.2060 
— 0.6785 
— 0.4863 
4- 
0.112 
1 
O 
O' 
i 
21 
21 
— 0.2224 
- 0.7255 
— 0.4143 
+ 
0.313 
4 0.027 
22 
23 
— 0.2279 
- C.7394 
- 0.3893 
+ 
0.066 
— 0.209 
23 
26 
— 0.2361 
— 0.7586 
- 0.3509 
+ 
0.453 
4- 0.195 
24 
27 
— 0.2388 
— 0.7646 
- 0.3379 
+ 
0.182 
— 0.070 
25 
April 
27 
— 0.3236 
— O.8308 
4 0.0949 
4 
CO 
O 
d 
4- 0.043 
26 
2q 
— 0.3290 
— O.S271 
4- 0.1229 
4 
0.176 
4- 0.151 
27 
30 
— 0.3318 
— 0.8249 
4 0.1373 
4 
0.070 
4- 0.048 
28 
May 
6 
— 0.3481 
— 0.8070 
+ 0.220S 
- 
0.018 
4- 0.003 
29 
7 
- 0.3509 
— 0.8033 
4- 0.2342 
- 
0.081 
- 0.053 
30 
8 
- 0.3535 
- 0.7993 
4 0.2478 
4 
0 
b 
£ 
(0 
4 0.077 
31 
25 
- 0.3998 
— 0.6984 
4 0.4659 
- 
0.098 
4- 0.054 
32 
26 
— 0.4026 
— 0.6906 
+ 0.4777 
— 
0.301 
- 0.143 
33 
27 
- 0.4053 
— 0.6826 
4 0.4895 
- 
0.158 
4- 0.007 
34 
28 
— 0.4081 
- 0.6745 
4 0.5010 
- 
0.239 
— 0.067 
35 
30 
- 0.4135 
— 0.6576 
+ 0.5237 
— 
0.249 
— 0.065 
36 
June 
26 
- 0.4874 
— 0.3680 
+ 0.7633 
- 
0.292 
4- 0.037 
37 
28 
— 0.4928 
— 0.3428 
+ 0.7753 
- 
0.423 
— 0.061 
i 
38 
July 
1 
— 0.5010 
— O.3045 
4 0.7917 
- 
0.342 
4- 0.006 
39 
2 
- 0.5037 
— 0.2916 
4 0.7967 
- 
0.297 
4 0.054 
40 
19 
- 0.5505 
— 0.0598 
4 0.8473 
- 
0.538 
- 0.139 
41 
21 
— 0.5560 
— 0.0320 
4 0.8487 
- 
0.340 
4- 0.063 
42 
23 
- 0.5615 
— O.OO44 
4 0.8492 
- 
0.287 
4- 0.119 
43 
24 
— 0.5641 
4 O.OO95 
4- 0.8491 
— 
0.373 
4- 0.034 
44 
25 
— 0.5668 
4 O.0234 
4- 0.8487 
- 
0.408 
0.000 
45 
28 
- 0.5752 
4- 0.0653 
4 0.8461 
- 
0.382 
4 0.029 
46 
Aug. 
22 
— 0.6433 
+ 0.3976 
4- 0.7434 
- 
0.411 
— 0.016 
47 
23 
- 0.6459 
4- 0.4090 
4 0.7370 
— 
0.411 
— 0.017 56 
THE PARALLAX OF a AND 61 CYGNI. 
612 Cygni—Continued. 
No. 
Date. 
Equations. 
Residuals. 
Wt. 
48 
1881. 
Aug. 24 
x — 0.6486y 
+ 
0.42132; 
+ 
0.7297u 
n 
0.386 = 0 
4- 0.005 
1 
49 
25 
— 0.6513 
+ 
0.4332 
+ 
0.7224 
— 
0.378 
+ 0.015 
50 
26 
— 0.6541 
+ 
0.4453 
+ 
0.7147 
- 
0.372 
+ 0.014 
5i 
Sept. 5 
— 0.6816 
+ 
0.5588 
+ 
0.6265 
- 
0.403 
— 0.048 
. 
52 
6 
— 0.6841 
+ 
0.5683 
+ 
0.6x76 
— 
0.352 
0.000 
53 
24 
— 0.7332 
+ 
0.7264 
+ 
0.4149 
— 
0.275 
— 0.003 
54 
26 
— 0.7386 
+ 
0.7401 
+ 
0.3896 
- 
0.379 
— 0.118 
55 
27 
- 0.7417 
+ 
0.7474 
+ 
0.3753 
- 
0.283 
— 0.027 
56 
29 
- 0.7471 
+ 
0.7598 
+ 
0.3492 
— 
0.315 
— 0.070 
57 
Oct. 22 
— 0.8100 
+ 
0.8356 
+ 
0.0282 
- 
0.041 
+ 0.062 
58 
26 
— 0.8210 
+ 
0.8355 
- 
0.0297 
- 
0.025 
+ 0.051 
. 
59 
27 
— 0.8237 
+ 
0.8349 
- 
0.0442 
- 
0.052 
4- 0.017 
60 
Nov. 4 
- 0.8455 
+ 
0.8206 
- 
0.1587 
+ 
0.092 
+ 0.107 
61 
5 
— 0.8483 
+ 
0.8177 
- 
0.1729 
- 
0.085 
- 0.077 
62 
29 
— 0.9138 
+ 
0.6747 
- 
0.4868 
+ 
0.229 
+ 0.080 
63 
Dec. 1 
— 0.9192 
+ 
0.6568 
- 
0.5098 
+ 
0.064 
— 0.096 
64 
4 
- 0.9273 
+ 
0.6287 
- 
0.5430 
+ 
0.238 
-t- 0.060 
• 
65 
5 
— 0.9302 
+ 
0.6186 
- 
0.5540 
+ 
0.225 
+ 0.041 
66 
7 
- 0.9377 
+ 
0.5984 
— 
0.5750 
+ 
0. hi 
— 0.084 
Reducing these equations by the method of least squares, we have the following 
systems of normal equations: 
a Lyrce, A. 
// 
-f- 69.0000 x + 5.2625 y — 3.7646 z + 17.3642 u — 6.4710 zz o 
+ 9-3897 V + 5.9664 z + 3.9279 u — 0.5670rzo 
4-22.2484^— 3.6682 u -f- 0.6975 zz o 
+ 31<9473 u~ 5-7437 = 0 
The sums of the coefficients of the four unknown quantities were used as a check in 
this part of the work, and denoting the sum of the coefficients in the normal equations 
by 2, the reduction gave, 
[as] zz + 87.8621 : 
2a — + 87.862 1 : 
[bs] — + 24.5462 : 
2b zz + 24.5465 : 
[cs] zz + 20.7826 : 
2c — + 20.7820 : 
[*] = +49-5721 : 
= +49-5712: 
[ws] zz — 12.0834 : 
2n — — 12.0842 : THE PARALLAX OF a LYR.E AN!) 61 CY .ML 
57 
The values of 2 were used in the elimination. From the solution of the normal equa- 
tions we have 
x — + 0.0593 ± 0.00510 weight = 57.5209 
y — —0.0491+0.01484 “ = 6.7960 
z = + 0.0175 + 0.00940 “ =16.9264 
22 — +0.1556 + 0.00764 “ =25.6622 
The residuals found by substituting these values of the unknown quantities in the 
equations of condition are given in the fourth column of the equations. The sum of 
the squares of these residuals is 
o".21300 
By elimination we have 
[/m.4] = o". 21386 
The probable error of an equation of weight unity is therefore 
rx = + q^.03869 
The value of this quantity, found from the discordances of the single nights, is 
. 0 -07365 . ,, 
+ _ .{A A — +0 .02329 
v 10 
The probable error found from the equations of condition depends on a greater 
variety of circumstances, and generally it will be the greater of the two. In the 
present case, however, the difference is not great, and we may infer from this that the 
observer’s manner of bisecting these stars did not change much during the period of 
observation. 
a Lyrve, B. 
It 
-f- 58.0000.2;-(- 1.6248y — 3.8841* + 12.7690a — 2.9620 = 0 
+ 7.2I77Z/+ 1.360822 + 0.0436 = 0 
+ 19.2877,? — 2.348922 + 0.9463 = 0 
+ 26.235822 — 5.5042 = 0 
[as] = + 68.5097 [bs] = + 16.1409 
= +68.5097 = +16.1396 
[cs] = +18.9918 [ds~\ = + 38.0171 
= +18.9910 2d — + 38.0167 
[22s] = — 7.4760 
2n — — 7.4763 
The values of the unknown quantities are— 
// n 
x = + 0.0056 + 0.00556 weight — 50.7511 
V — — °-°374 =t 0.01741 “ = 5-1589 
z — — 0.0111 + 0.01069 “ — 13.6974 
u = + 0.2080 + 0.00827 “ 2=22.8916 58 
THE PARALLAX OF « LYRvE AND 61 CYGNI 
The sum of the squares of the residuals is 
o". 18490 
From the elimination 
[nn. 4] = o//.i 8556. 
Hence the probable error of an equation of weight unity is 
// 
= dz 0.03955 
The value found from the single nights is 
, o .07732 . ,, 
db—-A4A_=±o .02445 
V 10 
The values of the annual parallax of a. Lyrce found from the two series of 
observations are therefore— 
// // 
Illumination A, n — 0.1556 + 0.00764 
“ B, n = 0,2080 + 0.00827 
In such a case as this it is generally better to take the simple arithmetical mean of 
the two values, but as the weights do not differ much I have taken the mean by weight, 
and we have as the final result: 
n =V/.i797 ± (/'.005612 
The time required for light to pass from this star to our sun is 18.11 Julian years. 
If we apply the corrections to the assumed values of z/d, we have for 1881.0: 
// // 
111. A, z/d = — 44.259 + 0.005 I 
111. 13, z/d = — 44.306 + 0.0056 
These results indicate that the difference of declination was measured a little greater 
with the bright wires than with the dark ones. 
The values of y, the correction to the assumed value of the proper motion have 
the same sign, blit they have small weights, the interval of time being too small for 
an accurate correction of this constant. The values of z have opposite signs, and are 
of no importance. 
612 Cygni. 
The 66 equations of condition of this star give the following normal equations: 
+ 64.0000# — 25.91 i6y + 7.6854.2 + — 1.3940 = o 
+ 17.6961 y — 6.6255M +3.8300 = 0 
+ 24.2231,2— 2.8108#— 0.8082 = 0 
„ + 20.5 71811 — 9.9808 = o THE PARALLAX OF a LYRAi AND 61 CYGNI. 
59 
[a.s] = + 49.3498 
2a — + 49-3498 
[Is] ~ — 20.1500 
2b = — 20.1492 
O] = + 23.7889 
2c = + 23.7895 
[<&] =+ 14-7109 
2d =+14.7115 
[m] = + 8.3529 
2n — — 8.3530 
The values of the unknown quantities are: 
// // 
x — — 0.0470 dr 0.01121 weight = 23.7093 
y — — 0.0835 dr 0.02330 “ = 54890 
z ~ -|- 0.082 1 di 0.01184 “ =21.2360 
M=d" 04783 dr 0.01381 “ =15.6253 
The sum of the squares of the residuals is 
o".39331 
and from the elimination, 
[nn.4] =o//.39287 
The probable error of an equation of weight unity is 
h = dr 0T05458 
The value found from the measurements of the single nights is 
, o .081 14 . ,, sr 
dr , — drO .2566 
V 10 
The discordance between the two values of the probable error is greater than for 
a Lynr; and this might have been expected, I think, for the reason mentioned before. 
For the parallax of this star we have, 
7r = o,,-4783 ± c/'-o^Si 
The time required for light to pass from this star to our sun is 6.803 Julian years. 
The value of x gives for 1881.0 
J6 — — j 98A513 dr o".oi 12 
The unequal distribution of the observations with respect to the epoch has dimin- 
ished the weight of this determination of x. The values of y and z are greater than 
those found from the observations of a Lyrce, but it is doubtful if these corrections 
have any real significance. 
An examination of the columns of residuals shows that the observations of a Lyrce 
are represented in a satisfactory manner. For the field illumination the greatest residual 60 
THE PARALLAX OF a: LYRyE AND 6i CYGNI. 
is o". 120 5 and for the illuminated wires it is o". 160. The image of this star in our 
telescope is always surrounded with a mass of blue light, but in good seeing the cen- 
tral image is a small, round disk, that can be bisected with certainty. The observa- 
tions of 612 Cygni show larger residuals, the greatest being 0A209. It is very rarely 
that this star is well defined in our telescope; and generally it has a hazy, indistinct 
appearance, that varies from night to night, and gives rise to some uncertainty in the 
bisections. If the objective and eye-piece be accurately focused on a star, and then 
a spectroscope be placed at the eye-piece, the image of the star will be reduced to a 
fine line between the lines B and E of the spectrum. Towards the blue end of the 
spectrum the image of the star soon widens and flares out into a.broad, fan-like shape; 
while towards the red end of the spectrum the image widens slowly for some distance 
and gradually loses its fine sharp form. It is on account of this, I think, that stars of 
the color of 6i2 Cygni are not well defined by our glass. Still the error in the paral- 
lax arising from the bisections is not very great even in this case. It maybe objected 
that the coefficient of temperature of the micrometer screw depends on too few ob- 
servations, and this must be acknowledged. However, observations made since the 
close of the first series confirm the value of this coefficient already found, and I 
cannot doubt the reality of the result. Even if the value of this coefficient should be 
a little changed by future observations it may well be doubted whether the new 
coefficient should be applied to the preceding observations. 
The parallaxes of stars found by the differential method, which has been used 
here, are relative, or they are the differences of the parallaxes of the two stars. In 
order to get the absolute parallax of the bright star, we must add to the parallax found 
by observation the parallax of the small star. This might be done by means of the 
table of parallaxes for stars of different magnitudes given by W. Struve in his “As- 
tronomie Stellaire,” p. 106. Although the assumptions made by Struve on the dis- 
tribution of the stars in space seem plausible, yet this whole matter is so vague that I 
omit this reduction. 
I am indebted to Prof. Edgar Frisby for assistance in all the preceding reduc- 
tions. The important calculations have been made by us in duplicate, and independ- 
ent checks have been employed when possible. I hope, therefore, that no important 
errors remain in the work. OBSERVATIONS OF a LYR2F: 
WITH 
THE PRIME VERTICAL TRANSIT INSTRUMENT. 
1862-1867. 
These observations form the most accurate determinations of declination ever made 
at the Naval Observatory, and having- been undertaken for the purpose of finding the 
annual parallax of the star, as well as the correction of certain astronomical constants, 
I have examined the observations and their reduction in the hope that some valuable 
result might be deduced from this laborious work. Before beginning the observations 
special precautions were taken that this instrument should be in perfect order; its pivots 
were reground, and a new striding level was made by Mr. Wurdemann. The methods 
of observing and reducing seem to have been chosen by Prof. J. S. Hubbard, all the 
formula*, for the reductions having been written out by him, and the early reductions 
being in his handwriting. The method followed in the observations was the same as 
that employed by W. Struve with such success at Pulkova. Two systems of wires, 
seven in each set, were placed on each side the center of the field, and the instrument 
was reversed in each vertical, so that after a complete observation it was restored to 
its first position. The four transits observed over each wire gave a determination of 
the declination of the star, and in the reductions the observations of each wire were 
reduced separately. The reduction of the star’s declination, from apparent to mean 
place, was computed directly from the formulae for every tenth day, and then inter- 
polated for the time of its culmination. 
The following is an outline of this work: 
The instrument was in charge of Professor Hubbard from March 25, 1862, until 
his death, August 12, 1863. From that time until the end of the observations, April 
2, 1867, it was in charge of Prof. S. Newcomb. Professor Hubbard was assisted by 
Professors Newcomb and IIarkness, and Professor Newcomb by Professor IIarkness 
until November 8, 1865. After that time I was his assistant. The observations are 
distributed among these observers as follows: 
J. S. Hubbard, March 25, 1862-July 8, 1863, 93 observations. 
S. Newcomb, May 6, 1862-February 26, 1867, 180 observations. 
W. IIarkness, August 12, 1862—August 16, 1865, 74 observations. 
A. Hall, November 8, 1865-April 2, 1867, 82 observations. 
61 62 
THE PARALLAX OF a LYRyE AND 61 CYGNI. 
The reductions of the transits from which the apparent declination of the star 
was found were made by the following- computers: 
J. S. Hubbard reduced 119 observations. 
S. Newcomb reduced 118 observations. 
M. H. Doolittle reduced 66 observations. 
A. IIall reduced 108 observations. 
The computations for the reduction of the star from its apparent to its mean dec- 
lination were made as follows: 
J. S. Hubbard, March 10, 1862-January 27, 1864. 
S. Newcomb, January 27, 1864-September 30, 1865. 
A. Hall, September 30, 1865-January 2, 1869. 
In my examination of these observations I first made a careful comparison of the 
formulae used for the reduction to mean place, thinking that possibly some small error 
had been made in some of the periodical terms. No such error could be found. This 
examination was repeated by Professor Frisby, who could detect no error in these 
formulae. An independent check on these reductions was found by comparing with 
the Nautical Almanac. The reduction of the separate wires was made after the man- 
ner of Struve, and this is so simple and so easily revised that it is hardly possible for 
a systematic error to remain in this part of the work. • It appears then impossible to 
change the results of these observations, and they must stand as they are printed. 
The observations were then divided according to the observers, but it was appar- 
ent that such a division would not help the matter. Indeed, if equations of condition 
should be formed in accordance with such a division, these equations in some cases 
would not be suitable for a good solution. I then divided the observations into groups 
according to the time, and the means of these groups were taken by Professor Frisby. 
As these means show briefly and clearly the character of these observations they are 
given here. The columns give the Washington mean time of the mean of the observa- 
tions, and the seconds of the mean declination of the star. This declination is referred 
to 1860.0 for the years 1862, 1863, and 1864, and for the other years to 1870.0. 
The probable error of a declination from a single complete transit 
For his own work Struve found this error to be Judging, therefore, from 
the accidental errors, these observations ought to give trustworthy results. THE PARALLAX OF a LYRyE AND 61 CYGNI. 
63 
Washington 
Mean Time. 
6 
Washington 
Mean Time. 
<5 
Washington 
Mean Time. 
6 
Washington 
Mean Time. 
6 
1862. 
Apr. 1,7432 
n 
20.206 
1863. 
June 14, 2569. 
20.281 
1864. 
Oct. 21, 5200 
20.270 
1866. 
Feb. 19, 4692 
5I.4I3 
Apr. 20, 4918 
20.420 
Sept. 12, 1299 
20.397 
Nov. 8, 3378 
20.492 
Mar. 10, 6370 
51.407 
May 9,4732 
20.228 
Sept. 24, 6622 
20.334 
Nov. 27, 8843 
20.484 
Mar. 25, 5130 
51-342 
May 23, 2688 
20.345 
Oct. 12,8859 
20.270 
Dec. 22, 3507 
20.373 
Apr. 12, 0497 
51-333 
June II, 2169 
20.128 
Nov. 9,6363 
20.290 
1865. 
May 13, 3792 
51.102 
June 19, 3280 
20.358 
Nov. 20, 3570 
20.288 
Jan. ii,5335 
51-391 
May 24, 5985 
51.295 
June 29, 5002 
20.336 
Dec. 3,9006 
20.443 
Feb. 12,8735 
51-350 
June 20, 3586 
51.193 
July 18,9469 
20.168 
Dec. 20, 8236 
20.330 
Mar. 7,0129 
51.214 
July 3.9879 
Si-348 
Aug. 3,4046 
20.397 
1864. 
Mar. 23, 5177 
50.932 
July 13,6614 
5I.346 
Aug. 17, 8650 
20.395 
Jan. 15,9520 
20.320 
May 15, S717 
51.230 
July 27, 1675 
51-350 
Sept. 17. 2817 
19.980 
Jan. 31, 7061 
20.188 
June 5,2326 
51.262 
Aug. 13, 1779 
51.102 
Oct. 6, 8282 
20.082 
Feb. 26, 8367 
19.908 
June 27, 0063 
51.268 
Aug. 24, 0980 
5I.I55 
Oct. 19, 2359 
20.070 
Mar. 9, 0566 
19.980 
July 13,4613 
5I-I93 
Sept. 24, 5950 
50.953 
Oct. 26, 9731 
20.168 
May 22, 4370 
20.225 
July 26,7582 
50.917 
Oct. 5,4320 
51.016 
Nov. 16, 9150 
20 186 
June 12, 4021 
20.300 
Aug. 10, 8834 
50.792 
Oct. 18, 1971 
51.148 
Dec. 7, 8584 
20.300 
June 25, 1084 
20.140 
Sept. 8, 0563 
50.880 
Nov. 12, 9266 
51.104 
Dec. 20, 5237 
20.160 
July 6,8786 
20.080 
Oct. 27, 6705 
51.042 
Dec. 5, 4632 
51.192 
1863. 
July 16,4524 
20.140 
Nov. 10, 9619 
5T.423 
Dec. 22, 3520 
51-273 
Jan. 6,7265 
20.258 
July 27,0235 
20.244 
Nov. 23, 6965 
51.458 
1867. . 
Feb. 9,0520 
20.365 
Aug. 8, 3897 
20.238 
Dec. 16, 6337 
51.566 
Jan. 13, 1590 
51-504 
Mar. 8,4105 
20.288 
Aug. 26, 7394 
20.262 
1866. 
Feb. 2,0711 
51-443 
Apr. 3.2379 
19.791 
Sept. 15, 2858 
20.180 
Jan. 10,7150 
51.800 
Mar. 10, 4054 
51.180 
May 10, 2565 
19.932 
Oct. 8, 8879 
20.273 
Feb. 3,4002 
51.620 
The maximum effect of the parallax in declination will occur about June 27, and 
the minimum effect December 27. The values of S show that a positive value of the 
parallax will result from the observations of 1862, but those of 1863, 1864, 1865, and 
1866 will give a negative parallax; on the whole, therefore, a negative parallax would 
result. A curious diminution of the declination is shown in all the years during the 
first three or four months, and the different observers agree in this. Such a variation 
taken by itself would indicate a correction to the constant of aberration, but the 
fact of a negative parallax renders uncertain all deductions from these observations. 
Probably some annual disturbance in the observations or in the instrument occurred 
which will never be explained. A possible source of disturbance may be mentioned. 
At the time these observations were made the library of the Observatory was in a 
room adjoining the prime vertical room, and a stove, with pipe and chimney directly 
above it, was placed 20 feet south of the prime vertical pier. A fire was started in 
this stove in November, and kept going until April, it was assumed that the reversal 
of the instrument would eliminate the effects of the heat and smoke on the instrument 
and observations. Hut it would appear to be a doubtful policy to undertake a series 
of observations for the determination of the absolute parallax of a star, and for the 
correction of constants determined with the utmost care by Struve, under any other 
than the most favorable conditions. I11 view of the recent discussions 011 the constant 
of aberration, it would be an interesting and a valuable astronomical investigation to 64 
THE PARALLAX OF a LYRtE AND 61 CYGN1. 
determine the value of this constant in the latitude of our Observatory, and I hope our 
Prime Vertical Instrument may be refitted, and another and more successful attempt 
may be made. 
March 9, 1882. 
P. S.—Having made some more observations of the stars in h Persei for testing the 
value of the temperature coefficient of the screw of the micrometer, the equations of 
condition resulting from these observations are given below. In the case of the 
observations made during the present summer double distances were measured on each 
night, so that the equations from these observations are of equal weight with those 
given before. The value of one revolution of the screw at the temperature of 50° is 
assumed to be 9".9054. The fourth decimal is the unit of the independent term. 
Date. 
Equations of Condition. 
Residuals. 
1880. 
Dec. 15-16 
X — 
12. gy 
+ 
41=0 
+- 
88.1 
Dec. 18-20 
- 
19.1 
- 
12 
+ 
59-4 
1881. 
Jan. 14-17 
— 
22.3 
186 
. 
102.1 
July 19-21 
+ 
19.4 
+ 
37 
- 
42.6 
July 23-24 
+ 
19-3 
+ 
102 
+ 
22.8 
July 25-28 
+ 
20.0 
+ 
84 
+ 
2.1 
Dec. 10-15 
- 
16.6 
- 
13 
+ 
48.6 
Dec. 16-17 
- 
15.8 
- 
63 
- 
4-6 
1882. 
Jim. 23-24 
— 
31.6 
— 
182 
61.6 
July 28 
+ 
21.2 
+ 
92 
+ 
5-4 
July 29 
+ 
23-7 
+ 
82 
- 
14.4 
Aug. 14 
+ 
23-7 
+ 
21 
- 
75-4 
Aug. 19 
+ 
15.3 
+ 
138 
+ 
74-5 
The solution of these 13 equations by the method of least squares gives 
y — — 0V00039205 dr 0T00005619 
and the probable error of a single equation is db o".oo4i53. The value of the revo 
lution of the screw is therefore 
R, = R0 — 0V00039205 (0 — 50°) 
where 0 is the temperature according to the Fahrenheit thermometer. This result 
differs but little from that found before, p. 46. 
August 24, 1882.