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    Re: Lunars: this weekend at Mystic Seaport
    From: Greg Rudzinski
    Date: 2018 Apr 19, 08:33 -0700

    Ed,

    For telephoto lenses over 200mm it is good enough to use the Sun diameter as the yard stick. A high altitude image is best. Then divide minutes of Sun diameter for the date by measured pixels of the diameter. This gives minutes of arc per pixel good through the limited field of view on telephotos. Wide angles are much more difficult. See archives for that problem.

    Greg Rudzinski

    From: Ed Popko
    Date: 2018 Apr 19, 03:15 -0700

    Greg,

    What a lovely example.  I'm curious, how do you determine the angular value of a pixel?

    Perhaps you shoot the moon whoes diameter you can compute or find in the Nautical Almanac

    and then count pixels to find the ratio.

    Ed

       
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