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: http://www.astronomy.net/articles/10/intro.html  
 Дата изменения: Unknown Дата индексирования: Sun Apr 10 00:32:33 2016 Кодировка: Поисковые слова: asteroid  | 
 
			
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by
John Huggins
We start our photographic journey in the middle of the instrument located on top of Anderson Mesa, just outside the city of Flagstaff, Arizona.

        View of the Instrument's Center
The white buildings house a type of telescope called a siderostat. Each 
        houses a 0.5 meter 
mirror 
        which collects the starlight and sends it to a mirror system which guides 
        the light to a central building. These units are alt-az mountings. Each 
        axis is driven by a stepper motor through a step down transmission. The 
        whole siderostat assembly rides on top of a three point stand which sits 
        on top of three concrete pillars. These pillars are solid all the way 
        down to the bedrock to provide high stability. The little black ball in 
        the middle of the mirror is a retro reflector for laser beams behind. 
        These lasers form a very precise distance measuring system which keeps 
        track of the mirror's movements with respect to the bedrock. This measurement 
        system can track changes of less than 20 billionths of a meter.
After 
        the starlight hits the siderostat mirrors, additional mirrors guide the 
        light to a feedbeam tube system. Each siderostat sends its beam of light 
        down one tube. Each tube maintains a vacuum to eliminate beam deformations. 
        Shown here are three feedbeam tubes. Eventually, the instrument will have 
        six tubes. 
[Beginning] - [Next Page - Starlight Path]
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