234 



THE GUIDE TO NATURE 



this way he will after a few evenings 

 be surprised to find how much of the 

 sky he has already learned. 



If he possesses a small telescope he 

 will find with it remarkable nebulas 

 at N and M, Figure i, beautiful star 

 groups and clusters at A, B, O, R and 

 S, double stars at the points marked 

 D, and many other interesting objects. 

 Though in the beautiful groups of the 

 Pleiades but six stars are easily visible 

 to the eye, a small telescope will show 

 twenty or more, and a delicate photo- 

 graphic plate will show no less than 

 two thousand. This cluster is so dis- 

 tant that its light requires two hundred 

 and fifty years to make the journey 

 from it to us, and its stars are im- 

 mersed in and connected together by 

 faintly shining nebulous matter. The 

 cluster is thus known to be a physi- 

 cally connected group of stars. Very 

 recent investigations indicate, too, that 

 much of this nebulous matter is not 

 self-luminous, but is opaque matter, 

 which shines only because it is illum- 

 inated by the rays of the many nearby 

 suns. 



The Motion of the Moon. 

 The student of astronomy knows 

 that the differing aspect of the heav- 

 ens in the different seasons is wholly 

 due to the apparent motion of the sun, 

 which is seen by us to follow the 

 path YY V E, Figure i, among the 

 stars, completing the entire circuit of 

 the heavens in one year. The monthly 

 path of the moon does not depart from 

 this line, but our satellite is subject to 

 so many disturbances that it never fol- 

 lows exactly the same course among 

 the stars for any two months in suc- 

 cession. At 9 P. M. on November i 

 the observer may notice that the center 

 of the moon is at U, between Aries and 

 Pisces; from here it moves rapidly 

 eastward, passing above the Pleiades 

 and below the star at K, and reaching 

 the point W at 9 P. M., November 6. 

 Full moon will occur at 6 P. M. 

 November 3, at which time the moon 

 will be slightly to the east of the Plei- 

 ades. On November 6 at 6 A. M. ob- 

 servers south of the earth's equator 

 will see the moon pass over the bright 

 star at K, though as seen by us. who 

 are so much farther north, our satellite 

 will appear to pass below this star. 

 From here the moon will cross Gemini, 

 move very slightly below the bright 

 star Regulus, in the Lion, pass around 



the other half of the heavens and 

 finally again enter the evening sky and 

 be found at the point X, on Novem- 

 ber 21 at 9 P. M. It will again be 



Southeastern Nojc/zoat 



Figure 4. Appearance of the sun at sunrise on 

 November 7. Eastern observers will then see the 

 planet Mercury at the Point A. 



found in Taurus on December i, but 

 careful observation will show that its 

 course among the stars is a much more 

 southerly one than that which it fol- 

 lowed a month earlier. 



When the moon is below the equator 

 (as at X) it sets very far toward the 

 south ; when above the equator (as at 

 W) it sets far in the north and re- 

 mains above the ground much longer 

 than twelve hours. It is in the same 

 way and for the same cause that the 

 points of the horizon at which the sun 

 rises and sets are continually altering-. 

 The sun is farthest below the equator 

 and we have the shortest day on De- 

 cember 22 ; it is highest in the heavens 

 on June 22. The moon in a similar 

 manner passes from its lowest to its 

 highest position among the stars in 

 less than two weeks, and this is there- 

 fore the interval between the shortest 

 and the longest "Moon Day." 



The Planets in November 

 Mercury at the beginning of the 

 month is lost in the sun's rays ; on 

 November 7 it passes across the sun's 

 disc thus entering the morning sky, 

 where it reaches its greatest western 

 elongation on November 2.~k. For a 

 few days before and after this last date 

 it will rise nearly two hours before 

 .sunrise and may be detected low in the 

 dawn in the southeast. 



Venus is also rapidly approaching 

 the snn and will withdraw from the 

 evening heavens on November 27. 

 During the first part of the month it 

 may be seen very low in the southwest 

 after sunset, and if the observer will 

 persevere in the rather difficult task 

 of folloAving it with a small telescope 

 he will be well rewarded for his 



