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    Re: Reducing back sights
    From: Henry Halboth
    Date: 2004 Aug 10, 14:44 -0400

    Although Bowditch explains it somewhat differently, I believe you have it
    right. Bowditch subtracts the raw back sight from 180-degrees, then
    reverses the sign of the IC and Dip, which amounts to the same thing -
    just be careful as to when you subtract from 180-degrees.
    On Tue, 10 Aug 2004 07:50:17 -0300 Jim Thompson 
    > Neither Dutton's nor Bowditch explain back sight reduction in
    > sufficient
    > detail for me to be confident about the process.  My understanding
    > is this:
    > 1. Raw altitude = back sight.
    > 2. Corrected raw altitude: apply Index Correction and dip.
    > 3. Corrected hs = 180d minus corrected raw altitude.
    > 4. Then reduce the corrected hs as usual.
    > True, or bungled?
    > Jim Thompson
    > jim2{at}jimthompson.net
    > www.jimthompson.net
    > Outgoing mail scanned by Norton Antivirus
    > -----------------------------------------

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