ASTROXOMV WITH AN OPERA-GLASS. 



75) 



and, at nine o'clock in the evening, is below the large star. It is of the 

 seventh magnitude. With a large field-glass several smaller compan- 

 ions may be seen, and a very excellent glass may show an 8'5 magnitude 

 star almost hidden in the rays of the seventh magnitude companion. 



With the aid of the accompanying map of Ursa Minor, which is 

 the constellation to which the pole-star belongs, find the star Beta (/?), 

 which is also called Kochab (the star marked a in the map is the pole- 

 star). Kochab has a pair of faint stars nearly north of it, about one 

 degree distant. With a small glass these may appear as a single star, 

 but a stronger glass will show them separately. 



And now for Ursa Major and the Great Dipper — Draco, Cepheus, 

 Cassiopeia, and the other constellations represented on the map, being 

 rather too near the horizon 

 for effective observation 

 at this time of the year. 

 First, as the easiest object, 

 look at the star in the mid- 

 dle of the handle of the 

 Dipper (this handle forms 

 the tail of Ursa Major), 

 and a little attention will 

 show you, without the aid 

 of a glass, if your eye- 

 sight is good, that the star 

 is double. A smaller star 

 seems to be almost in con- 

 tact with it. The larger of 

 these two stars is called 



Mizar and the smaller Alcor — the Horse and his Rider the Arabs 

 said. Your glass will, of course, greatly increase the distance between 

 Alcor and Mizar, and will also bring out a clear difference of color 

 distinguishing them. Now, if you have a very powerful glass, you 

 may be able to see the Sidus Ludovicianum, a minute star which a 

 German astronomer discovered more than a hundred and fifty years 

 ago, and strangely enough, taking it for a planet, named it after a 

 German prince. The position of the Sidus Ludovicianum with refer- 

 ence to Mizar and Alcor, is represented in the accompanying sketch. 

 You must look very sharply if you expect to see it, and your opera- 

 glass will have to be a large and strong one. A field glass, however, 

 can not fail to show it. 



Sweep along the whole length of the Dipper's handle, and you will 

 discover many fine fields of stars. Then look at the star Alpha (a) 

 in the outer edge of the bowl nearest to the' pole-stai'. There is a 

 faint star, of about the eighth magnitude, near it, in the direction of 

 Beta (fi). This will prove a very difficult test. You will have to 

 try it with averted vision. If you have a field-glass, catch it first with 



Ursa Majoic. 



