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    Bygrave slide rule
    From: Steve Whiteside
    Date: 2010 Nov 17, 15:12 -0800

    Gary LaPook: Many thanks for publishing the scales for the Bygrave. I have not found a transparancy print sheet yet. However, I printed your scales and copied them at 102% and 103% and they fit very nicely around a 1.5-inch by 12-inch plastic Sink Tailpiece from ACE hardware. Skewed slightly to line up and taped seams. Coated with Krylon Crystal Glaze for waterproofing. The 6 in. cursor cylinder is made from a 6 by 11 transparent plastic slide-on report cover also clear taped on seam. The actual cursor is fine wire from stranded copper taped to the clear cylinder.
    I have worked several example problems and seem to get about 1 to 2 minutes of error, although occasionaly the error is 3 minutes.
    Working a 5-13-93 GMT 07h 33m 45s Kochab sight from DR 40d 15m N and 50d 15m W gave me Hc = 43d 28m. Computer says Hc = 43d 25.7m. Reworking the problem with D and L interchanged gave 43d 23m. The error reversed.
    I have wanted a Bygrave slide rule for years. Thanks to your scales I now have a working unit. I am also a pilot and have had GPS quit all of the way across Ohio while travelling KS to NJ. It quit on the return trip also. At that time I used Loran as an alternate. Now we may have to use Celestial.

    Again, many thanks, Steve Whiteside

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