204 



THE GUIDE TO NATURE 



which appears as a single star in a pow- 

 erful telescope, bul which in reality is a 

 pair of stars, as revealed by the spectro- 

 sc( >pe. The motii in of < lamma in the 

 line of sight is not a constant, but a 

 variable one, indicating two stars revolv- 

 ing in orbits about each other. 



I hie cast of Vega arc two smaller 

 stars which form a small equilateral tri- 

 angle with the bright star each side being 

 about two degrees. The northerly one 

 of this pair is the renowned "double 

 double." This star known to astronom- 

 ers as Epsilon Lyrae is a test of moder- 

 ately keen eyesight, for it appears to the 

 naked eye as a double star with com- 

 ponents of nearly the same magnitude. 

 In a telescope, and a small one at that, 

 each of the components appears as a 

 double. The spectroscope shows this 

 system to be even more complicated. 



One of the most interesting bodies in 

 the whole constellation is the Ring Ne- 

 bula, of unique appearance in the sky. 

 This may be seen in a five-inch telescope 

 when one knows where to look for it, but 

 it is small. It is found in a line between 

 Beta and Gamma Lyrae and about two- 

 fifths of the distance from the former 

 star. To see it in its glory one looks 

 at a good photograph such as the one 

 obtained by Professor Keeler with the 

 reflector of the Lick Observatory. This 

 negative was obtained only after a long 

 exposure, and even with the tw r o foot 

 mirror is small in size. The photo- 

 graph is enlarged to show better the 

 detail of the ring, and the small 

 nebulous star in its center. 



THE PLANETS IN SEPTEMBER. 



During the month the majority of the 

 planets are in unfavorable positions, and 

 are invisible. 



Mercury is an evening object at the 

 beginning of the month, but it is low 

 down and difficult to see. It passes the 

 sun on the twenty-fifth of the month. 

 Venus is a morning object moving to- 

 wards the sun, but it is lost in the sun's 

 rays. 



Mars has been an evening star since its 

 opposition a year ago this month. It 

 passes to the other side of the sun on the 

 twenty-seventh and is now invisible. 



Jupiter has been setting earlier each 

 night in the southwest, and it is visible 

 for but a few minutes after sunset. 



Saturn and its rings are, however, in 

 a fine position for observation. It rises 

 about eight o'clock. It is found in the 

 constellation of Aries about halfway be- 

 tween Algenib in the Square of Pegasus 

 and Aldebaran in the Hyades. There 

 are no bright stars near Saturn. The 

 rings show up well in a moderate tele- 

 scope. 



Uranus may be found from its position 

 in the sky map. 



A comet was discovered on the morn- 

 ing of Tuesday, August 9, by the Rev. 

 Joel H. Metcalf, of Taunton, Mass. The 

 comet found visually in right ascension 

 16 hours, 10 minutes, declination plus 

 15 degrees 20 minutes moving very 

 slowly a little north of w r est, was of the 

 eighth magnitude with a short faint tail. 

 It is visible in a small telescope and its 

 position at the time of discovery is indi- 

 cated on the map. 



