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    Re: Lunars: 10/27/2013
    From: Paul Hirose
    Date: 2013 Nov 03, 10:22 -0800

    One must "turn up the gain" to .01″ or higher to see a difference
    between 40 feet height of eye and 45 feet 10 inches:
    
    At 40 feet:
       83°23′12.394″ center to center, unrefracted
           1′41.625″ refraction
    
    At 45 feet 10 inches:
       83°23′12.394″ center to center, unrefracted
           1′41.603″ refraction
    
    Only the refraction (which is the decrease in separation angle
    between the body centers) is different. That's calculated from a
    troposphere model, but in the real world I believe small temperature
    gradients around the observer will have greater effect. In any event,
    the slight change in refraction is insignificant compared to the
    irregularity of the Moon's limb, which surely exceeds a tenth of an arc
    second.
    
    When I added 1000 feet to altitude, the unrefracted separation angle
    increased only .081″.
    
    The above values are intended to show the sensitivity of the angles to
    variation of height. I don't mean to imply my software is that accurate
    in absolute terms.
    
    --
    I filter out messages with attachments or HTML.
    
    

       
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