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    Margett's Tables/graphical longitude.
    From: Francis Upchurch
    Date: 2016 Jan 12, 22:01 -0800

    I have finally got round to printing these wonderful graphs onto A3 paper and put the whole thing together in a ring binder (see attached)

    The real wonder and beauty of this masterpiece  surprised me. It was  not so apparent in the small printed edition and the PDFs. 

    I'm not sure what the original looked like in terms of size and format, but A 3 Landscape format looks good to me.

    I have so far only done a couple of lunar clearance examples from the egs in the book and get very accurate results in only a few minutes.

    So this seems to have been a quick, easy and accurate graphical method to clear lunars, printed from hand engraved copper plates in 1790!

    It seems almost miraculous that one of these must have survived to be digitally scanned and then ,thanks to Frank and the internet, flashed over the pond to me and now printed out as a workable copy of the original over two hundred years later.

    Thanks also to Ken Muldrew who likewise made me aware of this "gem" as he calls it and see Ken's post of 26th April 2006 for an interesting technical description of how it was likely created originally back in 1790. Any more news or update on this Ken? 

    I intend to do a lot of lunars over the next few months and compare this with Fuller slide rule and Frank style clearance methods.

    If there are any other Margett enthusiasts out there, please tell me all about it!

    Best wishes,


    lunatic, Bygrave and Fuller and now Margett enthusiast.










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