252 



THE GUIDE TO NATURE 



THE HEAVENS IN DECEMBER. 



BY PROFESSOR ERIC D00LITTLE 0E THE 

 UNIVERSITY OE PENNSYLVANIA. 



December, the first of the winter 

 months, is signalized by the entrance 

 of the magnificent Dog Star, Sirius, 

 into the evening sky. This beautiful, 

 bluish star, the brightest star of the 



largest or the brightest of the stars. 

 It is, in fact, but three times as massive 

 as our own sun, though it is thirty- 

 three times as bright, revolving around 

 it in a period of fifty years is a dull, 

 but equally massive, companion which 

 emits but one twelve-thousandth part 

 as much light as the brighter star of 

 the pair. Just as Dean Swift imagined 



NOlgTH 



i-OoT H 



Figure 1. The Constellations on December 1, at 

 If facing east, hold East below. If facing west, hold \Y 



entire heavens, will be seen just emerg- 

 ing from the ground in the southeast 

 to remain shining brightly in the south- 

 ern sky throughout the winter months, 

 until it finally withdraws toward the 

 end of March. 



The wonderful apparent brightness 

 of this star is largely due to its near- 

 ness to us, for it is by no means the 



9 P. M. (If facing south, hold the map upright, 

 est below. If facing north, hold the map inverted.) 



and described the two inner moons of 

 Mars long before they were actually 

 discovered, so Voltaire, in 1752, in his 

 imitation of Gulliver's Travels, spoke 

 of a great satellite revolving about 

 Sirius on which his hero lived. The 

 companion was actually discovered 

 mathematically in 1884, an( l was first 

 seen with the telescope in 1862. 



