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    Re: USCG Student Sample Problems #1, #2 and #3
    From: Antoine Couëtte
    Date: 2013 Apr 25, 10:17 -0700

    RE : http://fer3.com/arc/m2.aspx?i=123663

    Hello Greg, and

    Hello Peter (further down)

    This post concerns the first of the (now) 4 problems built up and submitted by Greg.

    Regarding the 02 JUN 2013 SUN shot at UT=01:59:40, Greg, you wrote :


    To remedy this I have looked at my original notes which shows a UT 1:59:40 for 2 June 2013. Reworking using USNO shows quite a few changes which are shown highlighted on the attachment. There was a change in GHA, assumed longitude, Hc, Hs, Ho, and intercept. This should fix things I hope.


    I have no longer any problem now with your updated value. :-)


    Regarding the POLARIS shot at 05:00:31 UT, Greg, you wrote :


    Regarding Polaris. The Pub 249 reduction uses a Q value and a precession nutation correction that are rounded to the nearest minute of arc. I would not expect a close match to USNO or other programs.


    This seems to fully explain our 0.4' difference then. Good News !


    About POLARIS... and this concerns Peter Hakel this time (are you here Peter ??)

    " : http://fer3.com/arc/m2.aspx/Group-Project-USCG-student-sample-problems-Couëtte-apr-2013-g23602 "
    and from Auxiliary Position 24°N / 143°40' , observing Polaris at UT 05:00:31 at Sextant Height 23°04'1 (corrected for only Instrument Error), I got a Geocentric Height Ho = 22°52'0 (I concur with Greg's published value) and an intercept of -36.4' (Away) in Azimuth 359°5, hence an Observed Latitude of N 23°23'6 at time of observation UT 05:00:31 (or a shifted latitude of N 23°23'7 at UT 05:00:00).

    ": http://fer3.com/arc/m2.aspx/Group-Project-USCG-student-sample-problems-Couëtte-apr-2013-g23607 " to which I did not read a reply to.

    Peter, while all our other intercepts fully match to +/- 0.1 ' , I still can not reconcile this Latitude I found of 23°23'6 (or 23°23'7) with your value of 23°25'5 published in
    " http://fer3.com/arc/m2.aspx/Group-Project-USCG-student-sample-problems-PeterHakel-apr-2013-g23606 ".

    Any cue from your part, Peter ?

    Best Regards to all,


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