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    Re: Longitude by Sunrise example
    From: Jeremy C
    Date: 2010 Feb 5, 14:21 EST
    That's about what I got too Greg with LOP solutions; once I un-corrected my non-existent index error that I accidentally left in the program.
    To fully disclose my shooting situation, I was using a 6x Alidade on a gyro repeater for my shooting.  It has a nice set of colored filters including a strong ND filter on a turret to shoot all sorts of things both on the horizon and up to about 60 degrees of elevation.
    While the LOP errors could be considered reasonable on a small craft with less than ideal shooting conditions, low altitude sun sights have much greater errors than I am used to and therefore I don't like or particularly trust them.
    This next trip I will shoot some more to get a better spread of data.
    In a message dated 2/5/2010 1:32:26 P.M. Eastern Standard Time, gregrudzinski@yahoo.com writes:


    I worked your upper and lower limb sunset examples using a palm program to derive a standard LOP azimuth and intercept with the given GPS position of 16°33'N 129°7'E as A.P.,Height of eye 100ft., Pressure /Temperature correction from A4 of +3'. No index error applied.

    Sun L.L. 18:58:16 ZT
    Hs 0°0'
    Azimuth 294.3°
    Intercept 3.9' away

    Sun U.L. 19:00:48 ZT
    Hs 0°0'
    Azimuth 294.5°
    Intercept 2.2' away

    This shows that your observations with the naked eye were very good. The sunset Longitude solution should work out if a precise table or program is used.

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