CHAPTER XI. 
7458 V DELPHINI. 
R. A. 2o h 43 111 13 s .6; Dec. + 18 0 58' 01" (1900). 
The discovery of the variability of this star, from the bright hydrogen lines 
in its spectrum, was made by Mrs. Fleming at the Harvard College Observatory 
in December, 1890. The announcement of the discovery made in the Asirono- 
mische Nachrichten 127 , 5, gave the Right Ascension for 1900 as 2o h 41.3 m 
instead of 43.i m . The other published notes which have come to the writer’s 
attention concerning this star are as follows: 
Hartwig. Astronomische Nachrichten, 1 34 , 180, 307, 1894. 
H. M. Parkhurst. Astronomical Journal, 13 , 192, 1894; 15 , 20, 1895; 17 , 65, 1896; 
21 , 9, 1900; 23 , 8i, 1903. 
W. M. Reed . Astronomical Journal 13 , 63, 1893. 
Yendell. Ibid., 13 , 176, 195, 1893; 17 , 79, 1896. 
J. A. Parkhurst. Ibid., 16 , 178, 1896; 17 , 102, 397, 1897; 19 , 69, 1S99. 
Astrophysical Journal, 12 , 53, 1900; 14 , 176, 1901. 
Visual observations began in June, 1894, with the 6-inch reflector, which 
was supplemented during the summer of 1898 by the 12-inch refractor, and 
after March, 1900, by the 40-inch refractor. The magnitudes of the comparison 
stars were measured with the equalizing wedge photometer attached to each of 
the telescopes, connection being made with the three fundamental stars from 
the Harvard and Potsdam catalogues with the 6-inch, and carried to the fainter 
stars with the 12- and 40-inch. Photographs of the field were made with the 
24-inch reflector, insuring the correct identification of the comparison stars, and 
furnishing a check on their coordinates from the variable, which were measured 
with the micrometer on the 6- and 40-inch. 
POSITION OF THE VARIABLE. 
The variable was connected with the micrometer on two nights, 1896 October 
24 and 26, with the star x, which is B. D. T 18° 4619, and whose place from the 
Berlin A. G. Catalogue is: 
R. A. 
Dec. 
Year. 
Berlin A. G. Catalogue 8389. 
Precession for 25 years. 
Berlin A. G. Catalogue 8389. 
Difference, variable minus x . 
Place of variable. 
h m s 
20 41 25.02 
4- 1 08.12 
20 42 33.14 
+ 0 40.5 
20 43 13.6 
O / * 
+ l 8 50 21.2 
+ 5 24.6 
+ 18 55 45-8 
+ 2 15.0 
+ 18 58 00.8 
1875 
1900 
1900 
This is in close agreement with the place found by Hartwig from heliometer 
measures, published in the Astronomische Nachrichten , 134 , 307. 
145 
