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    Re: Sextant practice, experimentation --Saturday in RI.
    From: Antoine Couëtte
    Date: 2013 Oct 3, 10:34 -0700

    RE : http://fer3.com/arc/m2.aspx/Sextant-practice-experimentation-Saturday-RI-Becker-oct-2013-g25252

    Hello M. "G" :-)


    Thanks for your help and reply.

    From Bruce's indications, I would surmise that he was observing close to position N41°27.0 - W071°23'9 (recknoned from Google Earth), but if Bruce reads us here (are u here, Bruce ?) we will get more accurate details.

    From the here-above position, and with USNO Celnav, I am getting :

    - for UT 16h36m38.0s (no tenths of seconds available) : H geoc UL = 24°14'3, with Z = 271.2°, and

    - for UT 16h37m43.0s (no tenths of seconds available) : H geox UL = 24°02'4, with Z = 271.4°

    We know that these USNO results do not take full account of the MOON parallax and SD which also depend on the Observer's Latitude. Hence they are accurate to +/- 0.15' by construction even if they were using super accurate Ephemeris data, which is very likely the case.

    I also computed own results believed to be accurate to +/- 4" in the worst case only due to "inaccurate" ephemeris, while I am performing 3D accurate SD and Parallax and Observer's Altitude Correction.

    Before I published compared results, I simply wish to ascertain the Observer's position as derived from Google Earth by Bruce and/or Frank.

    Standing by ...

    Thanks again and

    Best Regards

    Kermit


    Antoine M. Couëtte
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