TO KNOW THE STARRY JlIvWEXS 



51 



group. Hercules, with its wonderful, 

 closely packed cluster of sixt\- thousand 

 suns, (at A, Figure i) to its highest 

 position in the heavens. The summer 

 branch of the Milky Way has mounted 

 halfway to the zenith, and the part of 

 this including Delphinus, Aquila. Lyra 

 and Cygnus is unsurpassed in beauty b\- 

 any other like region of the heavens. 



The reader who is already familir^.r 

 with the brighter constellations and who 

 takes a pleasure in gradually becoming 

 acquainted with the no less interesting 

 but fainter and less well-known groups, 

 cannot do better than to select for his 

 study this month the long and winding 

 Dragon, for this group is now high above 

 the Pole, in its most favorable position 

 of the year. The head of the Dragon is 

 formed by the four stars at H (Figure 

 i) of which both B and C are interest- 

 ing binary systems, though they are ex- 

 cessively difficult, even in the largest 

 telescopes. The orange star at C will 

 always be a memorable one to astron- 

 omers, for it was from observations upon 

 this that the astronomer, Bradley, two 

 centuries ago, made the epoch-making 

 discovery of the so-called Aberration 

 of Light. 



From the region H, the body of the 

 Dragon extends downward to the yel- 

 lowish star F, and then upward, winding 

 around the Pole through AL meeting the 

 brightest star of the constellation at N., 

 and finally ending in the tip of the tail 

 at \\ The star at D is a beautiful pair 

 with an opera glass, the components 

 being separated 'by an apparent distance 

 equal to that across the full moon, and, 

 in fact, all the stars at J, U, E, F, L, M, 

 R and S are double stars, though many 

 of them are very difficult in the largest 

 telescopes. 



To the Arabians, the stars, J, B, C, and 

 H, were sometimes known as the Alother 

 Camels, protecting their foal, at U, from 

 the two Wolf Stars, K and L, who were 

 lying in wait for it. The foal is a little 

 pair of stars, easily seen double in a small 

 telescope. The brightest star of the 

 Dragon, at A, was the Pole Star of forty- 

 seven hundred years ago ; the central pas- 

 sage of the great pyramid of Cheoos was 

 directed to it, as indeed, were similar 

 passages in many other of these struc- 

 tures. During forty-seven centuries the 

 slow course of the procession has carried 



our pole from this star to Polaris (at W) 

 while six thousand years from now the 

 pole star will be the bright object at O, 

 and in twelve thousand years it will be 

 the magnihcent Vega. 



The reader may now also well trace out 

 the long, winding Serpent of the south- 

 ern heavens, with Ophiuchus, the Ser- 

 pent Holder, who is holding the twining 

 Serpent in his hands. The portion of 

 the Milky W'ay below and to the left of 

 this group is wonderfully rich in clouds 



Figure 2. The eclipse of tlie moon, July 14-15, 1916. 



and clusters, and indeed its whole sum- 

 mer branch is so filled with intricate 

 detail and variety that it will well reward 

 many evenings of careful exploration. 

 ^ ^ ^ ^ ^ 



The Planets in July. 



Mercury reached its greatest western 

 elongation on June 30 and for the first 

 few days of the month will be seen shin- 

 ing brightly in the dawn for about one 

 hour before sunrise. It should be looked 

 for well to the north of the east point 

 of the horizon. On July 28 it will enter 

 the evening sky but it will not attain its 

 greatest distance east of the sun until 

 September 9. 



A'enus enters the morning sky on July 

 3 and toward the end of the month will 

 become a conspicuous object there. It 

 will attain its greatest brilliance on 

 August 9. 



Alars, the only planet remaining with 

 us. will pass from Leo well into Virgo 

 during the present month. In a moder- 

 ately large telescope the polar cap and 

 the larger markings may still be made 

 out. but this world is now far too dis- 

 tant to be observed to advantage. To the 

 naked eye it is now even fainter than a 

 first magnitude star; in the telescope it 

 has the shape of the moon when about 

 three days past full. 



