POPULAR ASTRONOMY 



287 



imperceptible degrees, as the twilight 

 lights fade away, the shadow bow rises 

 higher, the golds and pinks above be- 

 come less pronounced, the shadow bow 

 fades into the darkening sky, and night 

 comes on. Thus can we realize that 

 the earth casts a shadow. 



but is inclined to it by a small angle, 

 a little more than five degrees. To have 

 an eclipse of the moon, our satellite 

 must pass into the earth's shadow, or 

 in other words, the moon and sun must 

 be on opposite sides of the earth, the 

 moon rising at sunset and the moon 



nov. moon Phases 



NEWMOON Nov 

 FIRST Qtr. Nov I0!b 

 FULL MOON Nov. 16$ 

 LAST Qtr. Nov. 2.3? 



Evening SkyMap for November 



- NORTH 



Columbia 



SOUTH 



MAP 



FOR 

 9KMJ5 



8PM 15* 

 7PM-3QS 



The ArrowThrough. 



THE TWO STARS IN THE 



BOWL OF THE BIG DIPPER 



POINTS TO THE NORTH STAR. 



THE 5TAR AT THE END OF THE 



HANDLE OFTHF. LITTLE DIPPF.R. 



As everyone knows, the earth moves 

 in her orbit about the sun in the eclip- 

 tic (so called because eclipses occur 

 only when the moon is near it). If the 

 moon moved in her orbit also in the 

 ecliptic, there would be two eclipses 

 each and every month. At the time of 

 new moon our satellite would come be- 

 tween us and the sun, and there would 

 result an eclipse of the sun. A fort- 

 night later, the moon would pass into 

 the shadow cast by the earth and a 

 lunar eclipse would take place. But 

 the moon's orbit is not in the ecliptic, 



full. Since the earth and sun are in 

 the plane of the ecliptic, the earth's 

 shadow is likewise in this plane, and 

 an eclipse of the moon can occur only 

 when the moon is near the ecliptic — or 

 expressed in technical terms — near her 

 node. If the moon is in the ecliptic at 

 the time of full moon, she will pass 

 through the centre of the earth's 

 shadow, and a long total eclipse will 

 result. The farther the moon is from 

 the eclipse at the time of full moon, the 

 shorter will be the duration of totality. 

 Evidently it is easy to calculate at 



