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    Re: Planet rising
    From: Steven Wepster
    Date: 2002 Feb 2, 22:16 +0100

    Dear David,
    
    If you are willing to use HO249 instead, I propose the following
    method. It's not exact to the minute.
    
    Look up the declination of the planet for the date you're interested
    in and round to the nearest degree. Open HO249 on the page corresponding
    to your latitude (whole degrees) and planet's declination, paying
    attention to 'SAME' or "CONTRARY' signs for those values. Select the
    right column for declination; in this column go up or down until
    you find altitude Hc = -0;34 or as close to it as you can. On this line
    you find two LHA's: one on the right and one to the left of the table.
    Take out those LHA's and add (or subtract, depending on E or W) your
    longitude. Now you have two GHA's which correspond approximately to the
    GHA of the planet at rise and set. Look up those GHA's on the daily page
    in the almanac under your planet to get the times of rise and and set. For
    this you will have to do reverse interpolation.
    
    If you insist on using HO229, you can follow essentially the same method,
    but it is a lot more clumsy because HO229 has one LHA per page, so you
    have to flip pages back and forth until you find Hc ~ -0;34 in the right
    row and column.
    
    Success,
    
    _Steven.
    
    
    -----------------------------------------------------------
    Steven Wepster                          wepster{at}math.uu.nl
                                            tel +31 30 253 1186
    Mathematisch Instituut
    Universiteit Utrecht
    PO Box 80.010
    3508 TA Utrecht
    The Netherlands
    ===========================================================
    
    
    

       
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