54 



THE 6O-INCH REFLECTOR. 



In modern astrophysical research the eye has 

 given place to the photographic plate, which in 

 almost all cases records much more than the eye 

 can perceive. As the reflector is especially adapted 

 for celestial photography, this form of telescope 

 was chosen for our stellar work, for which the Snow 

 and tower telescopes are not suitahle. A 5-foot 

 mirror, already ground and partly polished at the 



. 



FIG. 40. Sectional Drawing of 6o-inch Reflector and Dome. 



^ erkes Observatory, was acquired for use on 

 Mount Wilson and brought to a perfect figure in 

 our optical shop in Pasadena. The heavy parts of 

 the mounting, some of which weigh 5 tons each, 

 were made at the Union Iron Works in San Fran- 

 cisco; while all of the more exacting work, requiring 

 greater precision, including the assembling of the 

 instrument, the cutting of the teeth of the lo-foot 



