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    Re: Davis MK III Index Error
    From: Fred Hebard
    Date: 2015 May 10, 22:16 -0400
    Isn’t the usual method is to touch one image to another, measuring the semi-diameter?

    Fred Hebard

    On May 10, 2015, at 10:11 PM, Brad Morris <NoReply_Morris@fer3.com> wrote:

    Hello Herman

    Superimposing the sun's image onto itself or the moon's image onto itself is a highly effective method of determining the index error. 

    Just watch that you don't blind yourself by observing the sun without shades!  That pain you feel in your eye is a warning!  (Slight humor should be noticed here!)


    On May 10, 2015 5:07 PM, "Herman Dekker" <NoReply_Dekker@fer3.com> wrote:

    Thanks for the info.
    There is no free sight around possible in the backyard. It is dark now, so I used Venus, that works. The index error is now back from 55' to zero, as long as it stays with a plastic sextant. Is a high cloud with a sharp edge usable for index error? This is just an idea, as nothing else is possible?

    Frank can you explain: What is the Sun test on the Moon?



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