738 THE POPULAR SCIENCE MONTHLY. 



PLEASURES OF THE TELESCOPE. 



By GAERETT P. SERVISS. 

 IV._VIRGO AND^HER NEIGHBORS. 



FOLLOWING the order of right ascension, we come next to 

 the little constellations Crater and Corvus, which may be 

 described as standing on the curves of Hydra (map No. 8). Be- 

 ginning with Crater, let us look first at a, a yellow fourth-magni- 

 tude star, near which is a celebrated red variable R. With a low 

 power we can see both a and R in the same field of view like a very 

 wide double. There is a third star of ninth magnitude, and bluish 

 in color, near R on the side toward a. R is variable both in color 

 and light. When reddest, it has been described as " scarlet," 

 " crimson," and " blood-colored " ; when palest, it is a deep orange- 

 red. Its light variation has a period the precise length of which 

 is not yet known. The cycle of change is included between the 

 eighth and ninth magnitudes. 



While our three-inch telescope suffices to show R, it is better 

 to use the five-inch, because of the faintness of the star. When 

 the color is well seen, the contrast with a is very pleasing. 



There is hardly anything else in Crater to interest us, and we 

 pass over the border into Corvus, and go at once to its chief 

 attraction, the star 8. The components of this beautiful double 

 are of magnitudes three and eight; distance 24", p. 211; colors 

 yellow and purple. 



The night being dark and clear, we take the five-inch and turn 

 it on the nebula 3128, which the map shows just under the border 

 of Corvus in the edge of Hydra. Herschel believed he had re- 

 solved this into stars. It is a faint object and small, not exceed- 

 ing one eighth of the moon's diameter. 



Further east in Hydra, as indicated near the left-hand edge of 

 map No. 8, is a somewhat remarkable variable, R Hydrse. This 

 star occasionally reaches magnitude three and a half, while at 

 minimum it is not much above the tenth magnitude. Its period 

 is about four hundred and twenty-five days. 



While we have been examining these comparatively barren 

 regions, glad to find one or two colored doubles to relieve the 

 monotony of the search, a glittering white star has frequently 

 drawn our eyes eastward and upward. It is Spica, the great gem 

 of Virgo, and, yielding to its attraction, we now enter the richer 

 constellation over which it presides (map No. 9). Except for its 

 beauty, which every one must admire, Spica, or a Virginis, has no 

 special claim upon our attention. Some evidence has been ob- 

 tained that, like ^ Auriga?, it revolves with an invisible com- 



