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    Re: Margetts' 1790 Longitude Tables
    From: Ed Popko
    Date: 2018 Jan 26, 12:28 -0800

    Frank,

    Much appreciated, thanks for sending.  The blood drains out my head thinking of the effort to compute these by hand and then etch plates. I can not imagine how a private individual could make a profit from their calculation and publication. Only government printing offices could take this on. (Confession - PostScript programming has ruined me.) 

    For myself, the thing to learn from them is to develop an sense of how the altitudes of bodies, observed lunar distances and their Delta z's affect clearing. Aside from the actual application of his graphs and their historic contribution, one could learn how and at rate these variables influence the cleared distance.

    What a work!  

       
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