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    Re: Sun Azimuth
    From: Bill B
    Date: 2013 Jan 09, 17:55 -0500

    A quick way to get a pretty accurate azimuth for rise or set if you know
    your latitude:
    
    Estimate sunset or sunrise time for your lat and estimated long using
    the almanac.
    
    Calculate the declination for the approximate time of rise or set.
    
    Locate the refraction correction for 0d upper limb in the almanac. It
    will be -49!7 plus/minus 0!1. Use this as your HC.
    
    Use your lat, HC and declination in the standard equations for
    calculating azimuth.  No extra tables or equations needed. This should
    also work for stars or planets using -33!8 as your HC.
    ===================================
    
    Time of sunset or rise given exact lat and long.
    
    Swap out the HC and declination above. Use the standard azimuth equation
    and it becomes a classic time sight yielding LHA.
    
    LHA combined with your long determines your target GHA.
    
    Subtract the hourly almanac GHA just smaller than the GHA you calculated
    above and convert arc to time. (The same as determining LAN given
    longitude.)
    
    The UT of the hourly almanac you used plus the arc to time from above is
    your UT rise or set within the limits of low-angle refraction gremlins
    and bodies being extinguished by the atmosphere.
    
    Bill B.
    
    
    
    
    
    
    
    

       
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