RE: unid LEO

From: Ted Molczan (molczan@rogers.com)
Date: Tue Jul 06 2004 - 07:37:32 EDT

  • Next message: David Brierley: "DMB Obs Jul 5-6"

    Ed, a circular orbit fit to your revised two timed positions and site
    coordinates, yields a 66.5 deg, 847 km orbit, reminiscent of the 71 deg Tselina
    2 orbit, home to the bright Zenit rocket bodies.
    
    IDSat turned up 95058B:
    
    Cosmos 2322 r   10.4  3.9  0.0  3.9 v 22.7
    1 23705U 95058B   04185.23630873  .00000335  00000-0  19812-3 0  1317
    2 23705  71.0150 233.6838 0013423 302.4703  57.5121 14.14779453447863
    
    The only problem is that I had to widen the search to +/- 5 minutes of your
    reported time, and 95058B was nearly 3 min earlier than you reported. However,
    its track agrees rather well with all three observed positions, and the time
    difference is about the same for both timed positions:
    
    Relative your 03:58:20.3 UTC position, it was 173.32 s early and within 0.32
    deg.
    
    Relative your 03:58:34.5 UTC position, it was 173.35 s early and within 0.11
    deg.
    
    Are you absolutely certain that your reported times could not have been late by
    173.32 s?
    
    I know you took some other timings that night, for example, in a private message
    you mentioned having clicked on Topex at 3:55:41.5 UTC. You observed it just
    prior to the UNID, but your timing of it is 24.5 s later than the first of your
    timed UNID positions, assuming that it was 95058B. Of course, if there was a
    systematic error in your time calibration/reduction, then all of your times
    would be 173.3 s late.
    
    That would put your Topex timing at 03:52:48, at about az 207, el 24 deg, fairly
    early in its pass, consistent with your comment that you probably watched it a
    minute or even two after that, because it was quite bright. 
    
    That accounts rather well for the time leading up to your next planned
    observation: Landsat 5, which was due to exit the penumbra at about 03:56:58
    UTC, near az 81, el 69 deg. If your UNID was 95058B, then your first un-timed
    position was at 03:55:00 UTC, which makes sense, because it preceded Landsat 5.
    
    Ted Molczan
    
    
    
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