4 
RESEARCHES IN STELLAR PHOTOMETRY. 
(6) At least three standard stars should be used in each series; the measures 
of a field should be made on at least three nights; three settings of the pho¬ 
tometer on each star (repeated as specified under (2), making six settings in all). 
Experience convinced the writer that three settings were as good as four, with 
the added advantage that three could be kept in mind and recorded at once. 
(7) The use of too dark a shade glass (see Chapter I) should be avoided, a 
change as great as two magnitudes in the background had an injurious effect 
on the measures. 
Table 1 gives the selected list of variable stars in whose fields the investi¬ 
gations were conducted, with a summary from the following chapters of the periods 
determined and the magnitudes at maxima and minima. The positions given 
were (with the single exception of RU Herculis) measured with the filar microm¬ 
eters on the 6- and 40-inch telescopes. 
Table 2 summarizes the visual observations of the variables, giving the num¬ 
ber, limiting dates, and resulting number of maxima and minima. 
Table x.—List of Variable Stars. 
Star. 
1900. 
Period. 
M-m. 
Range. 
RightAscension. 
Declination. 
Max. 
Min. 
h m s 
0 / n 
d 
d 
Mag. 
Mag. 
103 T Andromedae. 
0 17 10.0 
+ 26 26 27 
284 
126 
8-5 
13.0 
267 V Andromedae. 
0 44 39-7 
+ 35 6 30 
259 
111 
9.0 
14.0 
787 W Andromedae. 
2 11 14.1 
+ 43 50 26 
396 
192 
7-5 
13-8 
4315 R Comae. 
11 59 8.4 
+ 19 20 19 
361.8 
119 
8-5 
14.0 
5798 RU Herculis. 
16 6 2.7 
+ 25 19 56 
484 
217 
7-5 
14.0 
firnn RV Hprrulis. 
16 56 44.7 
+ 31 22 18 
200 
81 
9.7 
15.3 
6894 S Lyrae. 
19 9 6.3 
+ 25 50 17 
438 
i 54 
10.0 
15.0 
7220 S Cygni. 
20 3 24.7 
+ 57 4 i 52 
326 
162 
10.0 
16.7 
7269 SX Cygni. 
20 11 33.2 
+ 30 45 58 
409 
i 73 
9.0 
14.0 
7458 V Delphini. 
20 43 13.6 
+18 58 1 
529 
161 
8 
17 
8518 Z Cassiopeiae .... 
23 39 39-9 
+ 56 1 33 
492 
i 73 
10. 2 
i 5 - 2 
8629 Y Cassiopeiae. 
23 58 138 
+ 55 7 25 
410 
158 
9 -1 
14.0 
Table 2.—Summary of Visual Observations of the Variables. 
Star. 
Number 
of obser¬ 
vations. 
Began— 
Number of— 
Jc,naea— 
Max. 
Min. 
103 
T Andromedae. 
i 73 
1894 Mar. 
1905 Nov. 
11 
12 
267 
V Andromedae. 
109 
1897 Jan. 
1905 Dec. 
10 
10 
787 
\V Andromedae. 
75 
1899 Feb. 
1905 Dec. 
6 
6 
4315 
R Comae. 
132 
1894 Mar. 
1905 Aug. 
8 
10 
5798 RU Herculis. 
136 
1897 Jan. 
1905 Oct. 
6 
6 
6100 RV Herculis. 
55 
1897 Aug. 
1905 Nov. 
14 
13 
6894 
S Lyrae. 
110 
1896 Oct. 
1905 Nov. 
8 
6 
7220 
S Cygni. 
100 
1892 Dec. 
1905 Dec. 
9 
8 
7269 
SX Cygni . 
75 
1899 Oct. 
1905 Nov. 
5 
5 
7458 
V Delphini. 
140 
1894 June 
1905 Dec. 
7 
6 
8518 
Z Cassiopeiae. 
100 
1898 Nov. 
1905 Nov. 
4 
4 
8629 
Y Cassiopeiae. 
100 
1898 Feb. 
1905 Nov. 
7 
7 
U 405 
95 
93 
