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    Re: Lunars with Young's formula: always off by several minutes
    From: Frank Reed
    Date: 2018 Oct 31, 16:42 -0700

    Aha. Yet another step added to the process that makes it difficult to debug! :)

    May I ask, why are you calculating GHA from RA like this?? What process are you envisioning? You mentioned that you didn't want to have any tech on the boat. That's fine. You can set your rules for the game however you like. But what would you be using for almanac data? Surely not something listing RA values. The standard Nautical Almanac (in various incarnations) lists GHA data. While you're on land, just use the USNO web app here:

    And what are you calculating from GHA's? If you want predicted LDs so that you can interpolate between them, then maybe it would be easier to go ahead and print out some lunar distance tables? I'm attaching an example from my website. If you ever do an ocean voyage using lunars, you could easily print them out for a few weeks of sailing. Just make sure you also have the required tables to calculate Local Time, too (I taught a class in that process, using historical, late 19th century tables, just last weekend at Mystic Seaport).

    Frank Reed


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