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    Re: Sextant double reflection: angles halved
    From: David Pike
    Date: 2021 Feb 15, 17:22 -0800

    David - I sent my proof a bit ago, but damn, yours is about 10 times simpler!  Love it!

    Except I was too slick.  You have to consider direction of bending.  A better argument is:

    Letting clockwise be positive, starlight is bent (180-2v) - (180-2u) = Minus Theta, so Theta = 2(v-u)

    For triangle ABC, (90-v) + (90+u) + Phi = 180, or Phi =  v-u,  so Theta = 2 Phi.  Got there in the end. Sorry.  DaveP  

       
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