Re: Iridium Question

From: Tony Beresford (
Date: Sun Mar 19 2000 - 19:18:58 PST

  • Next message: Dale Ireland: "Re: Iridium Question"

    At 08:13 20/03/00 , Jonathan T Wojack wrote:
    >What is the inclination of the Iridium satellites?  
    86 degrees.
    >Once their orbits are
    >lowered, how bright might they get
    At a perigee of 250Km and directly overhead they would be about
    mag 3,so easy enough naked eye. They are a binocular object any
    time they are sunlit at the moment. get some predictions of
    heavens above and have a look.
    > and is it possible to watch them decay?
    That depends on what the satellite operators actually DO.
    But you can track them with binoculars whether they are Flashing or not.
    To bring them down takes time. As I said before this means maintaing
    satellite attitude as far as I can guess.
    I suspect they might try and make the satellites get to
    burn up well south of the equator if they can, just so
    as to be seen not creating problems for the board of directors,
    there arent many people south of 50s after all!! 
    Such a procedure only works if the orbit is still eccentric
    when it decays, and re-entry occurs at perigee. This usually
    only happens with Molniya satellites. A recent Molniya
    decay was observed by many inhabitants of Western Australia,
    as it tracked from Albany on the south coast , to
    the timor sea/indian Ocean north of Wyndham, a distance of
    several thousand Km. 
    Tony Beresford
    34.96S, 138.633E
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