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    Re: Multi-Moon line exercise in 2 parts
    From: UNK
    Date: 2009 Aug 5, 10:30 -0700

    Aug 05, 2009
    Dear Jeremy,
    Subject to double checking my computation - which I have not done yet - and 
    working through your example, and assuming that "0.8 arc minute on the arc" 
    means :" from instrument value uncorrected for error, substract 0.8 arc 
    minute to get such value corrected for error ", I would suggest the following 
    results, with TT-UT = 66.0 Seconds of time :
    UT of Moon Culmination as seen from moving observer : 9h51m42,6s
    Diffrence between Culmination and Transit times : 2s8 . The observer has a 
    definite speed towards south ( 13.16 kts south speed component), but - 
    interestingly enough - the moon has a declination decreasing by almost the 
    same value, as its declination goes 12.85 '/hour towards the south. Therefore 
    it explains why both effects almost cancel each other out. This is why both 
    Culmination and Observer's True Meridian transit are so close, by only 2.8 
    seconds of time.
    UT of Moon transit observer's Meridian (i.e. Moon passing due south of moving 
    observer) : GMT 9h51m39s8, or LT = 18h51m39s8
    Position at time of Moon Transit trough crossing observer's meridian :
    N2149.5E13003.7 (sorry I am using Air Navigation Computers notation, since I 
    am an Airline Pilot, which means : 21�49'5 N , and 130�03'7 E )
    SDEV of measures is 0.6 NM, which gives a Latitude error of 1.0 NM with 2 
    sigma and a longitude error of 3'8 with 2 Sigmas.
    At 09:00 UT (18:00 LT) , DR position was  N2200.8E13006.5 as reckoned from the 
    09h51m39s8 observed Moon fix
    At 10:00 UT (19:00 LT) position was N2147.7E13003.2 DR, same as above
    At 11:00 UT (20:00 LT) position was N2134.5E13000.0 DR, same as above.
    LAST POINT : If I have made Instrument corrections the wrong way, then I need 
    to rework your example with instrument corrected values higher by 1'.6 than 
    the one I have used. As a consequence, with the assumption that this 1'.6 
    angle change should/will have no significant effect on both Parallax values 
    and Refraction values as well, then Observed Latitudes will be 1'6 to the 
    south and Observed Longitudes are unchanged by reference to indicated 
    positions hereabove.
    Just be so kind as to confirm me that I have done Instrument error removal in 
    the right direction. I somewhat unfamiliar with the terms "ON the Arc" and 
    "OFF the arc".
    Thanking you for your Kind Attention and Awaiting your reply, I am remaining,
    Most Sincerely Yours
    Antoine M. Cou�tte
    One last question : With such a Height of eye .... where have you been 
    observing from ? an Aircraft Carrier upper deck ? (e.g; USS John F. Kennedy 
    114 ft !!! )
    [Sent from archive by: antoine.m.couette-AT-club.fr]
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