146 
researches in stellar photometry. 
THE CHART. 
Plate 11 shows the field around the variable on a scale of i3."8tothe millimeter. 
It is a six-fold enlargement from a negative taken 1902 September 7, exposed 
from 9 h 17™ to io b 25™, Central Standard Time, with the 24-inch reflector. 
The negative shows the star A, 16.3 magnitude, distinctly. The photographic 
magnitude of the variable on this plate is 10.4, which is 0.6 fainter than the visual 
brightness as given by the light-curve, fig. 32. This difference corresponds 
approximately to a color of 4 on Chandler’s scale. 
Table 89.—7458 V Delphini. Standard Magnitude Stars. 
1900. 
Color 
P.DM. 
Magnitude. 
Residuals. 
Star. 
B. D. No. 
R. A. 
Dec. 
Catalogue. 
Measured. 
From Cats. 
3 
Nights 
inter 
se. 
H.C.O. 
P.DM. 
H. 
P. 
H. 
P. 
F 
O 
+ 19 4501 
h m s 
20 40 17 
0 / 
+ 20 07.9 
GW 
7.07 
7.11 
7.0 2 
7.28 
- 5 
+ 17 
±4 
G 
+ 19 4544 
20 47 50 
+ 19 45-4 
GW 
7.22 
7 95 
7-55 
7.81 
+ 33 
-14 
±2 
K 
+ 19 4555 
20 49 38 
+ 19 22.7 
WG 
7.40 
7.40 
7.11 
7-37 
-29 
- 3 
±4 
Mean .... 
7 23 
7-49 
7.23 
7-49 
± 22 
± 11 
±3 
THE COMPARISON STARS. 
The data for the comparison stars are collected in Tables 89, 90, and 91, 
which are sufficiently explained by the headings of the columns. The difference 
between the mean magnitudes of the three fundamental stars in the Harvard 
and Potsdam catalogues, 0.26, is larger than usual, which seems to be due to the 
Harvard magnitude for the star G being 0.3 or 0.4 too small. The mean of three 
measures in October, 1883, is given as 6.91 in Harvard Annals, 24 . The mean 
of three measures in September, 1894, is given as 7.52 in Volume 44 of the same 
Annals. Whether this difference is due to error in the first set of measures or to 
a change in the star itself remains unexplained. 
Table 90.—7458 V Delphini. Comparison Stars in B. D. Catalogue. 
Star. 
B. D. 
1855- 
Star. 
B. D. 
1855. 
No. 
Mag. 
R. A. 
Dec. 
No. 
Mag. 
R. A. 
Dec. 
C 
•> 
0 
n 
0 
+ 18 4602 
+ 19 4500 
+ 18 4611 
+ 18 4614 
8.2 
8.0 
S. 8 
9 -i 
h m s 
20 37 56 
20 38 14 
20 40 2 
20 40 13 
0 t 
+ 18 59 -3 
+ 19 hi 
+ 18 43.9 
+ 18 55.5 
»' 
m' 
X 
k 
O 
+ 18 4617 
+ 18 4618 
+ 18 4619 
+ 19 4513 
9.2 
9.0 
8.9 
9-4 
h m s 
20 40 26 
20 40 29 
20 40 31 
20 40 43 
O t 
+ 18 39.7 
+ 18 43.2 
+ 18 45.6 
+ 19 2.0 
