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    Re: Lunar distance accuracy
    From: Bill B
    Date: 2007 Oct 26, 05:27 -0400

    > Frank,
    >
    >> Yes. The human eye certainly has higher resolution in daylight. I think we
    >> discussed this at length a couple of years ago, didn't we?
    >
    > Sure. But as it always happens, there was a long
    > discussion with different opinions and I don't remember
    > whether it came to a definite conclusion.
    >
    > One alternative explanation offered was that
    > the eye pupil becomes larger in the darkness:-)
    >
    > Alex.
    
    In the process of moving while trying to care for an aging mother hours
    away, so please excuse my lack of specific detail. Frank pointed out an
    excellent article in, if memory serves, Sky & Telescope a while back that
    dealt with corrective surgery, night eyeglass prescriptions, and the lack of
    ability to resolve a point source as the eye night adapts. Please check the
    archives and/or read the article.
    
    Unless you are a submariner trying to distinguish a horizon in the dead of
    night, I feel there is a strong case to be made for keeping the pupil small.
    Some list members I have met personally find an IE check with a star very
    difficult.  Ironically, night myopia appears to decrease with age. Some
    texts (Bauer?) recommend popping out and and doing the observation so one
    does not strain the eye. Unless absolutely necessary, I try to keep the
    pupil as small as possible and get better results.
    
    I would be hard pressed to make a case for depth of field being a factor for
    a target that is, for all practical purposes, at infinity.
    
    Bill
    
    
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