Re: geosync flasher

From: Bjoern Gimle@GlocalNet (Gimle@GlocalNet)
Date: Mon Feb 02 2009 - 19:35:49 UTC

  • Next message: Joseph A. Dellinger: "geosync flasher"

    For a satellite in high orbit, its rotation axis usually precesses <0.1 
    deg/day, and most often near the poles, and the reflecting surface normals 
    are often at near right angle to the axis.
    This means that the main change is the Sun's apparent motion +4m in RA, and 
    a little in declination, and the reflections then move around -4m in RA
    Then run predictions to see when the satellite passes closest to that moved 
    For a geostationary this should be about 8 min earlier.
    But if the trace of the reflections crosses the track of the satellite at a 
    small angle, the small change in Sun's declination will cause a much larger 
    change in RA, and the direction depends on the sign of the angle. And if the 
    reflections don't follow a great circle, they can disappear from the track 
    ----- Original Message ----- 
    From: "Joseph A. Dellinger" <>
    To: <>
    Sent: Monday, February 02, 2009 7:03 PM
    Subject: geosync flasher
    > As a "1st guess", how much should the timing of flashes be
    > expected to drift a day, and in which direction? Maybe I should go
    > try to catch that flasher again. I had planned to look for it
    > again on Saturday night but was clouded out.
    > -------------------------------------------------------------------------
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