Re: Ground-based image of STS+ISS

From: George Roberts (
Date: Thu Jun 28 2007 - 12:17:16 EDT

  • Next message: Jeff Umbarger: "Re: Ground-based image of STS+ISS"

    >I'm impressed...
    >I've just put my 8 inch scope in the trash can !!!
    Thanks for the chuckle!
    ... or how to make a good satellite photography system:
    The telescope used to take this picture is a 15 minute drive 
    from my house and I have visited it about 6 times.  It 
    belongs to a private school for K-12 (this isn't the only 
    impressive part of the school by a long shot - this is a very 
    rich school).  The telescope has a mirror that was ground to 
    much better smoothness and figure than typical mirrors of 
    it's size (25 inches).  The telescope has an active adaptive 
    optics system that corrects only in x and y (some adaptive 
    optics systems have hundreds of correctors).  According 
    to Ron Dantowitz who runs the telescope a single corrector 
    fixes most of the atmospheric distortion.  I don't know if this 
    system works with photographs like this one where there is 
    no reference star.  But the seeing is very good at this location - 
    the telescope is mounted on the roof of a 4 story building (with 
    a pier that runs through all 4 floors into granite below - 
    vibrationally separate from the rest of the school) and 
    this building is on top of a hill, and typical winds run over 
    a large farmer's field before hitting the hill.  All this reduces 
    turbulence.  This telescope is used by the Navy each night 
    remotely (after Ron goes home) to search for planets 
    around other stars using laser-spectroscopy and Ron 
    seems to think it is the most accurate device on our 
    planet for this purpose because of the telescope's unique 
    features.  Located about 8 miles from light polluted Boston - 
    obviously one can do serious astronomy in light polluted skies.
    There is a picture of the building (and the telescope dome) in 
    the upper corner of this web page:
    - George Roberts
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