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    Re: Alternate methods of sight reduction
    From: Zvi Doron
    Date: 2005 Dec 7, 06:41 -0000
    Hi Jim
     
    I must run so it will be short - sorry
     
    I have studied the Bygrave slide rule and built several working models including developing a piece of software to draw the scales - to my mind the Bygrave is the most practical way of reducing a sight for a small boat where accuracy of 1 mile is perfectly acceptable.
     
    Kind regards
     
    Zvi
    ----- Original Message -----
    From: Jim Hickey
    Sent: 06 December 2005 20:47
    Subject: Alternate methods of sight reduction

    Alternate methods of sight reduction
     
    First, allow me to introduce myself as a new member. My name is Jim Hickey.  My wife Judy and I currently live aboard our sailboat in St. Augustine, Florida. I have been interested in celestial navigation for many years much to the amusement and entertainment of my wife! Even got the programming bug early on but have it under reasonable control at this time. It has been a delight to read many of the fascinating postings for some time now.
     
    I have a volume of Bowditch that discusses a variety of sight reduction methods. I believe all the old table methods and more have been discussed. Has anyone had access to or knowledge of the old slide rule type method that is referenced? I believe the instrument was called a Bygrave computer which looked cylindrical.
     
    As well, there is also a picture of a wonderfully elegant looking globe like device that is set up with sliding arms that solves the navigational triangle directly.
     
    I have been intrigued by these items for years and of course would love to mess with them if I had the chance as I am sure many here would.
     
    Very curious to know how effective these approaches were and if there are others etc. etc.
     
    Cheers,
     
    Jim
       
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