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    Re: F. Barker & Son Box Sextant
    From: Sean C
    Date: 2016 Apr 10, 04:00 -0700

    Brad,

    The distortion was not present in the direct view of the bodies through the telescope, even when I rotated the telescope about its longitudinal axis. No matter what longitudinal orientation the telescope is in, the distortion is always apparent only on the reflected image and always in the same direction (roughly 45° from vertical). I also noticed that when I looked at some distant trees without the telescope installed, the reflected image seemed to be blurred slightly. (Curiously, using the peep hole seems to reduce the amount of distortion, but it also reduces the amount of light getting through considerably.) During all of these observations, no filters were in the optical path. The telescope extends to a length that is slightly greater than the diameter of the sextant case. I even tried looking at stars and planets with the telescope pushed mostly inside the case, the objective lens being only about a millimeter from the horizon mirror. Same result - distortion on the reflected image. The entire inside of the case (including the back of the brass filter slot cover and filter frames) has a matte grey finish, These things lead me to believe that it is a defect in one, or both, of the mirrors.

    Thanks for your encouragement and interest in this problem. I really do appreciate it. On the bright side, a friend of mine says he knows someone who might be able to assist me with fixing both the mirrors and stripped screw. It seems my luck just may hold up. :)

    Regards,

    Sean C.

       
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