APPENDIX II 
267 
between the two stars. Since the curvature of the orbit is very small, the practical error of this 
assumption can not be very serious for ten or fifteen years to come. It is hardly necessary to 
remark, however, that the value of this as a fundamental star is impaired by the circumstances 
described. The catalogue-place is that of the mean. In order to determine the position of a 2 the 
quantities taken from the following table must be added to the catalogue-position for the respec¬ 
tive years. To get the corresponding positions of a 1 , reverse the signs of the table and apply as 
before. 
Date. 
Aa. 
A 8 . 
Date. 
Aa. 
A 8 . 
1 755 
-!o86 
// 
+ I-S4 
1864 
S 
— .186 
-1-3° 
1757 
-.088 
+ X.50 
1872 
— .184 
—1.48 
1800 
— .148 
+ .44 
1880 
— .180 
—1.64 
1808 
-.158 
4- .22 
1888 
-•173 
-1.79 
1816 
— .166 
.OO 
1896 
— .164 
— x.92 
1824 
— .172 
- -23 
1900 
-.158 
—1.96 
1832 
-.178 
- -45 
1904 
-.152 
— 2.00 
1840 
— .182 
- .67 
1912 
-.138 
-2.05 
1848 
— .184 
- .89 
1920 
— .120 
— 2.06 
1856 
— .186 
— 1.10 
1924 
— .110 
— 2.04 
No. 2008. a Canis Minoris. Procyon. 
The annual parallax may be taken as 0V33. After trial it was found that none of the published 
orbits of this binary could be satisfactorily reconciled with the meridian-observations of the bright 
star and the micrometrical observations of the fainter star at the same time. Accordingly, a new 
orbit was computed by successive approximations. The result gave for the ratio of masses, 1: .33, 
the bright star being the more massive. These are the resulting orbits: 
Bright Star about the Center of Gravity. 
T = 1886.5 
Period = 39.0 years 
Q - 3 3 o°7 
i = 14.2 
u = 36.8 
a = i'/oo 
e - .324 
Faint Star about the Brighter. 
T = 1886.5 
Period = 39.0 years 
0 = 150^7 
i = 14.2 
36.8 
a = 4V05 
e = .324 
The orbit is, of course, very uncertain, though the ratio of the masses is fairly well determined. 
The observation of the double is very difficult; and the meridian-observations on a star so bright as 
this are very liable to be affected with anomalies. The following table indicates the results of 
comparison of the orbit with the micrometrical observations published in Burnham's General Cata¬ 
logue of double stars, in the sense, C- 0 : 
Observer. 
Epoch. 
0-e„ 
c 0 
Pc-Po 
Nights. 
Observer. 
Epoch. 
0 -0 
c 0 
1 
0 
Nights. 
Schaberle 
1896.93 
0 
-2.8 
ft 
— .OI 
4 
Barnard 
1899.07 
0 
+.03 
n 
+ •03 
3 
Aitken 
1897.0 
- 3 -o 
— .21 
4 
Aitken 
i 8 qq.q 6 
4-1.4 
4-. 10 
3 
Hussey 
1897.16 
— 0.6 
-•03 
3 
Barnard 
1900.05 
4-0.4 
-.07 
6 
Schaberle 
1897.82 
—1.0 
+ .08 
6 
Lewis 
1900.23 
-0.9 
4 -.23 
1 
See 
1897.83 
- 4-3 
— .06 
I 
See 
1900.29 
+ 5-3 
4 -.46 
4 
Boothroyd 
1897.83 
“ 5-2 
-.08 
1 
Aitken 
190X.20 
4 - 4 -i 
+ .01 
2 
Aitken 
1897.88 
— 0.1 
+ .04 
3 
Barnard 
1901.88 
+ 2.5 
4-.12 
2 
Aitken 
1898.21 
+ 0.5 
-.04 
2 
Lewis 
1902.21 
4-2.8 
-•17 
2 
Barnard 
1898.21 
— 0.2 
-•05 
6 
Hussey 
1902.24 
+ i -3 
4 -.11 
1 
Lewis 
1898.24 
— 0.1 
+ •52 
I 
Barnard 
1903-15 
-t-1.4 
4 -.11 
3 
Hussey 
1898.28 
+ 1.2 
4- .28 
1 
Aitken 
1905.14 
- 3-9 
+ •17 
1 
Aitken 
1898.76 
-1.8 
-.07 
3 
