PROJECTS 569 



from it (K N-S, Figure 4) would be identical with the horizon line 

 (TD), and there would be no angle, 0. From this it can be seen that, 

 in order to measure our latitude, we need only measure the angle of 

 the North Star above the horizon. 



Your calculations may be as much as one degree off, one way or the 

 other. But if you will make your observations on a night when the 

 constellation of Cassiopeia is just as high above the horizon as the 

 North Star, you will get accurate results. See the " Boy Scouts' Hand- 

 book," p. 96, and Figure I, on page 10 of this book, and report on this 

 to the class. 



PROJECT IV. Star Projects Varying with the Seasons, pages 1-18 



The two other constellations in the northern heavens that are 

 shown in the diagram on page 10 are Cepheus and the Dragon 

 (Draco) . After you are able to locate with certainty the other three 

 constellations we have talked about, you will probably be able to 

 trace these two constellations. 



Two of the best known stars in the northern heavens are Vega 

 and Arcturus. The two stars forming the inside edge of the Big 

 Dipper next to the handle form a line which points past the head 

 of the Dragon toward a large, brilliantly white star. This is Vega. 

 The two stars that form the bottom of the Little Dipper form a 

 line pointing away from the Pole toward a very bright reddish star 

 of the first magnitude. This is Arcturus, mentioned on page 7 

 of this book. 



Since the earth, by reason of its revolution around the sun as 

 well as its rotation, gradually changes its position in relation to the 

 stars, there is a noticeable change of the evening sky map from month 

 to month. The best way to make a study of the evening sky for 

 any particular month is to obtain a copy of the "Monthly Evening 

 Sky Map," l a little journal for amateur astronomers. By means 

 of this, from month to month, you may identify the planets, im- 

 portant constellations (such as Scorpio, in midsummer ; and Orion, 

 in midwinter) and important stars, including Sirius, the Dog-Star, 



1 "The Monthly Evening Sky Map," Leon Barritt, Publisher, 367 

 Fulton Street, Brooklyn, New York. 



