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    Re: CP-300/U Star Finder
    From: Brad Morris
    Date: 2015 Mar 8, 20:07 -0400

    Hello Ed

    I enjoyed your article and purchased one of these units off of eBay.  

    I've been thinking about that (up to) 5° shift in the latitude for the azimuthal equidistant overlays. 

    Consider a 10° latitude.  We can move the 5° overlay up to 10° or the 15° latitude down to 10°.   But now consider, the 5° and the 15° overlays have unique shapes so there must be some error associated with either when used at 10° latitude.

    In order to determine this, I may have to resurrect the 2102e, so a mathematical result can be obtained.

    Alternatively, one could pull out two sequential overlays to the 2102d and directly observe the error.

    I wonder if your research had led you down this path?


    On Mar 7, 2015 4:02 PM, "Ed Popko" <NoReply_EdPopko@fer3.com> wrote:

    Marine navigators have used the 2102-D star finder for many years as an aid to planning sights or identifying stars.  The U.S. Air Force developed a variation in the mid-1950s called the CP-300/U that incorporated a number of useful enhancements.

    I wrote this article some years back for the “The Navigator’s Newsletter” History of Navigation column (Issue #77  Fall 2002 pp.6-12) but no one seemes to have ever heard of this device or know what it fate was. Perhaps someone here has additional information.

    Ed Popko

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