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    Is the focus on the mirror or on the star
    From: Randall Morrow
    Date: 2017 May 23, 21:39 -0700

    I am puzzled. I have been told that when I look at a reflected star image I am focussing on a body at infinite distance. That makes sense intuitively and with optics of things seen in mirrors on earth. But, if that is the case with a star, why do I have to adjust focus as I move toward or away from the mirror to take sights. There is no doubt about this. It is an indisputable fact. I have seen this in thousands of sights. If my focus is on the star at infinity I should not have to change my focus. Please explain this. My suspicion is, that since vision happens in the brain and not the eye, that my focus is the surface of the mirror  a few feet away and not the star at infinity. Please comment.

    Kind regards,

    Randy

       
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