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    Reducing back sights
    From: Jim Thompson
    Date: 2004 Aug 10, 07:50 -0300

    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
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