Re: Heavens-Above set to south pole

From: Gerhard HOLTKAMP (
Date: Tue Apr 19 2005 - 16:44:52 EDT

  • Next message: Tom Wagner: "Re: Heavens-Above set to south pole"

    >I just tried to look up information about what iridium flares would be 
    >visible for the next 7 days as seen from the south pole. I get none. Can 
    >someone else try H-A and see if they get anything? I may have done something 
    Fascinated by the subject I did some South Pole Iridium Flare calculations 
    with my own program. The special geometry between an observer at the South 
    Pole, the direction of the Sun and the Iridium orbital planes which changes 
    only gradually during one day leads to certain days experiencing flares all 
    the time with no-flare days in between. On APR 15/16, APR 29/30, MAY 10 and 
    MAY 14/15 (2005) you can experience mag -8 monster flares every 9 minutes all 
    day long. A particular satellite which has flared will apear once again after 
    one orbit 1h40min later in almost the same relative position and cause 
    another flare. The flare position in the sky (with regard to the background 
    stars) stays the same (which means it will rotate in azimuth around the sky 
    during the day). After about a day the geometry has shifted a little and the 
    flares get weaker, then disappear before a few days later another orbital 
    plane and antenna-Sun geometry will cause another series of flares.
    The whole thing really works because on the South Pole the elevation of the 
    Sun stays essentially constant all day long.
    Gerhard HOLTKAMP,
    Darmstadt, Germany
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