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    Re: Star to Star Distance Sextant Calibration
    From: Alexandre Eremenko
    Date: 2019 Apr 10, 23:04 +0000

    Thanks, this is a useful tool.
    I made a similar one several years ago when I was doing a lot of star-to-star distances,
    (what else could I do with  sextants from my balcony in the middle of Indiana?)
    but since then my computer crashed and I lost my programs:-(
    The idea to share it and thus to preserve somehow did not cross my mind.
    From: NavList@fer3.com [NavList@fer3.com] on behalf of Michael Bradley [NoReply_Bradley@fer3.com]
    Sent: Wednesday, April 10, 2019 6:16 PM
    To: eremenko@math.purdue.edu
    Subject: [NavList] Star to Star Distance Sextant Calibration
    A crude new toy, automating by spreadsheet, in a limited way, a calibration 
    check on a sextant using star to star distances, is in the attached file.
    I searched the web for a while, couldn't find anything of the like.
    The planner section of the spreadsheet gives distances accurate enough to 
    pre-set the sextant and so ease the sight taking process.
    The calculator section does the precision work, but needs the green data boxes 
    filling. Please note that it is set up assuming the work is done 'all north'. 
    If a south declination star is chosen, you'll have to change the sign of its 
    decimal declination yourself. Ditto EPLat. I never said the spreadsheet was 
    Thanks to Frank Reed for 'Easy Lunars', from which parts needed for the calculator section were lifted.
    Thanks to Bill Ritchie - I've been using Astron for the almanac data, 
    calculated altitudes, and refraction values to put into the spreadsheet.
    The Winter Hexagon is in a prime position after sunset right now, at least for we northerners.
    It's seems sensible to use 'sideways' distances for large arcs, say more than 
    45 degrees. Lunar type sight technique is needed for that,
    but is not terribly dificult to do if the planning preset is used.
    No warranty offered or implied. Please use, modify, crit, suggest improvements etc as you might wish.
    Michael Bradley
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