PLEASURES OF THE TELESCOPE. 



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because they are so close that their light remains inextricably 

 mingled after the highest practicable magnifying power has been 

 applied in the effort to separate them. But the spectroscope 



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shows that the star is double and that its components are in rapid 

 revolution around one another, completing their orbital swing in 

 the astonishingly short period oifour days ! The combined mass 

 of the two stars is estimated to be two and a half times the mass 



