ASTRONOMY WITH AN OPERA-GLASS. 



199 



its surprising brilliancy. Two faint stars close to Vega on the east 

 make a beautiful little triangle with it, and thus form a further means 

 of recognition, if any were needed. Your opera-glass will show that 

 the floor of heaven is powdered with stars, fine as the dust of a dia- 

 mond, all around the neighborhood of Vega, and the longer you gaze 

 the more of these diminutive twinklers you will discover. 



Now direct your glass to the northernmost of the two little stars 

 near Vega, the one marked Epsilon (c) in the map. You will perceive 

 that it is composed of two stars of almost equal magnitude. If you 

 had a telescope of considerable power, you would find that each of these 

 stars is in turn double. In other words, this wonderful star which 

 appears single to the unassisted eye, is in reality quadruple, and there 

 is reason to think that the four stars composing it are connected in 

 pairs, the members of each pair revolving around their common cen- 



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Virgo and Bootes. 



ter while the two pairs in turn circle around a center common to all. 

 With a field-glass you will be able to see that the other star near 

 Vega, Zeta (), is also double, the distance between its components 

 being three quarters of a minute, while the two stars in c are a little 



