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    Re: How close without a good Lunar?
    From: Hewitt Schlereth
    Date: 2018 Jul 26, 07:13 -0700
    Francis, thank you for the 'mention in dispatches'. The Summer 1977 issue of Navigation magazine has an article by J.W. Luce that sets out another plotting-sheet version of Longitude w/o Time.

    Hewitt

    thanks On Jul 24, 2018, at 7:01 AM, Francis Upchurch <NoReply_Upchurch@fer3.com> wrote:

    I agree with Greg,

    I think we are talking about using lunar altitudes to estimate time/longitude? (not lunar distances)

    Letcher describes his method Ch 17 page 96.

    Chichester describes a simplified graphical method in Along the Clipper way page 170. This method is explained with worked example in Hewith Schlereth (yes, our very own!) Commonsense Celestial Navigation page 134.

    I've tried the Chichester graphical  method a couple of times, not very accurate (about 30-40  miles out) but probably better then nothing.

    Bye the way, Chichester was a bit naughty I  think, implying his idea was original. 

    He had Raper's Navigation circa 1840 on board to find out how to do lunars. He didn't like the maths so came up with his simpler altitude method..

    What he doesn't mention is that there is a whole chapter devoted to longitude by lunar altitudes in Raper! Albeit not his graphical  method, but surely he must have seen that to stimulate the idea? Nothing new under the sun (or moon!)

    Best wishes

    Francis

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