APPENDIX II 
2 73 
sequently the published material for computing the proper motion of £* is slender. Assuming the 
p.m. to be the same as that given for C 2 in the Catalogue, and that 
Aa = — 0^43 8 AS — + 3"40, for 1900 
as computed from the micrometrical observations, we have for 1900: 
£* Coronae, R. A. = 15 h 35 m 36^282. Decl. = 36° 57' 4o''49 
A few good determinations of the position of £ 2 at the present time would permit of a fairly 
accurate determination of p.m. from the meridian-observations. 
No. 4138. <r Coronae Bor. c.g., 2 2032. 
The companion is of 6 M 8. The orbit is adopted from See ( Stellar Systems). The period is 370 
years, and is, of course, very uncertain. But since periastron occurred early in the nineteenth cen¬ 
tury, the determination of the relative masses seems to be entitled to some consideration, though it 
is, of course, uncertain. For the coefficient of p in the expressions to designate the distance of the 
center of gravity from the bright toward the faint star we have: 
From R. A. = .46 ± .20 1 A , 
From decl. = 24 ± . I$ ) Adopted, . 3 , ± ,i 2 
If we put the mass of the bright star as unity, that of the faint star would be .47. It seems prob¬ 
able, at least, that the mass of the companion is not greater than that of the so-called principal 
star. Assuming the center of gravity to divide the distances in the proportion of .32 to .68, we have 
the numbers of the following table, which, added to the catalogue-place, will predict the place of 
the bright star. Multiplying the numbers of the table by —2.12 and adding in like manner, we 
derive the positions of the companion. 
Date. 
Aa. 
AS. 
Date. 
Aa. 
AS. 
Date. 
Aa. 
AS. 
1800 
S 
— .Ol6 
_ 
It 
.70 
1844 
S 
~.Ol6 
// 
+ -54 
1888 
+ .048 
It 
+ 1.18 
1804 
— .022 
— 
.66 
1848 
— .OIO 
+ -65 
1892 
+ •053 
+1.20 
1808 
— .027 
— 
•58 
1852 
— .004 
+ -74 
1896 
4-.058 
+1.22 
1812 
-.031 
— 
.48 
1856 
+ .002 
+ .82 
1900 
+ .063 
+ 1-23 
1816 
-•034 
— 
•37 
i860 
+ .009 
+ .89 
1904 
+ .067 
+ 1.23 
1820 
-.036 
— 
.24 
1864 
+ .015 
+ .96 
1908 
+ .071 
+1.24 
1824 
-.036 
— 
.11 
1868 
+ .021 
+ I.OI 
1912 
+ •075 
+ 1.24 
1828 
-•°3S 
+ 
•°3 
1872 
+ .026 
+1.06 
1916 
+ .079 
+ 1.24 
1832 
-.031 
+ 
•17 
1876 
+ .032 
+1.10 
1920 
+ .083 
+ 1.23 
1836 
— .027 
+ 
•3° 
1880 
+ .038 
+ 1.14 
1924 
+ .086 
+1.22 
1840 
— .022 
+ 
•43 
1884 
+ .043 
+ 1.16 
No. 4178. p Ophiuchi. 
This is W. H., II, 19. The magnitudes are 5^2 and 5^7. The stars are relatively very nearly 
fixed. The following expression gives approximately the reduction of the components to the 
mean, the upper signs corresponding to the principal star. 
Aa = T ?0I2 =F .0003 (r — 1900) AS = ± i''72 
The effective pointings of the early observers of this star probably relate to the mass; and they 
may be less nearly coincident with the principal star than with the mean of the two components. 
Later observers more often give results for both components. It is difficult to decide on the best 
course in a case like this; but it has been assumed that the earlier observers pointed on the mean; 
means were taken where observers give both components; and the foregoing corrections were em¬ 
ployed where a single component is specified. Thus the catalogue-place is intended to correspond 
to the mean of the two stars, though this can be considered no better than a fair approximation to 
the truth. 
We have for the two components in 1900: 
R. A. n n' 
North star 5 M 7: i6 h 19 111 35^229 — ?ooii — 23 0 12' 57' , 49 — ''021 
South star 5.2: 35.253 — -0005 13 0.93 — .021 
