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    Sextant double reflection: angles halved
    From: Richard Toohey
    Date: 2021 Feb 15, 09:29 -0500
    Thanks for that Sean. I turned away from your email fast enough to preserve my innocence but slow enough to know my rendering was similar to yours. So I think I’m on the right track!  Just need to find an elusive geometric relationship or two!  

    But it’s good to know where to go if/when I cry uncle!

    On Mon, Feb 15, 2021 at 1:50 AM Sean C <NoReply_SeanC@fer3.com> wrote:

    Richard,

    The proof is given on page 261 (Chapter 16, §1601) of the 2002 edition of Bowditch. I have also attached my rendering of it below.

    Of course, I understand if you still want to work it out for yourself. In that case: don't look at the attached picture. ;)

    Regards,

    Sean C.

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