RE: Lunar transit ?

From: Bruno Tilgner (Bruno_Tilgner@compuserve.com)
Date: Sat May 05 2001 - 15:44:53 PDT

  • Next message: Tony Beresford: "may 06 observation"

    Ted Molczan wrote:
    
    >The following object passed within about 0.2 of the centre of the lunar
    disk
    >about 84 s after the reported time of the transit:
    
    According to my calculation, Cosmos 1931 never came closer than 0.8 degree
    to the center of the lunar disc. This was between 21:21:25 and 21:21:28
    UTC.
    I am using the WGS84 model for the shape of the Earth, and this may explain
    the discrepancy. Another explanation might be the method to calculate the
    Moon's position. For this application I am using an algorithm given by
    Montenbruck/Pfleger in their book "Astronomy on the Personal Computer".
    I also have the Chapront-Touzé algorithms but I find that the added
    accuracy does not warrant the increase in calculation time for this
    kind of problem, the main source of inaccuracy being the TLEs and their
    evolution and not the motion of the Moon.
    
    Bruno Tilgner
    
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