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    Re: LAN calculations for GHA
    From: Tony Oz
    Date: 2020 Mar 26, 15:54 -0700

    Dear Adam,

    Did you get the 79°30' by multiplying the 17h18m by 15° and subtracting 180°? That's incorrect.

    You should have consulted the NA for the 12th of May (presumably - year 2005) at 17UT and add the GHA increment for the remaining 18 minutes. In the illustrative table you see 75°51,1' - that is the GHASun{at}2005-05-12UT17. Then you see the 4°30' being added - that is the GHA increment for the 18 minutes, thus the GHASun{at}2005-05-12UT17:18 = 80°25,1'.

    If the obtained GHASun value exceeds 180° - you are in the eastern longitudes, you should subtract GHA from 360° to get your longitude. So far, with GHASun = 80°25,1' < 180° you are in western hemisphere, no subtractions needed.

    Warm regards,
    Tony
    60°N 30°E

       
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