RE: Which NOSS 3-3 did I see?

From: Ted Molczan (molczan@rogers.com)
Date: Sun Feb 27 2005 - 08:52:11 EST

  • Next message: David Brierley: "DMB Obs Feb 27 a.m."

    Ed Light wrote:
    
    > I just saw one of the new NOSS objects - either 28537 = 05-004A or
    > 28541 = 05-004C, but cannot tell which it was.  The brightening sky
    > and the bright moon didn't help, but I definitely saw an object
    > pass near 2 UMi (HD005848 at 2000 coords 01:08.5 +86d16') at
    > 2005 02 27/05:43:41 +/- 3s EST (UTC 10:43:41 +/- 3s) in the expected
    > track as the two objects.  At my location, based on the TLEs below,
    > 28537 should have passed the star at UTC 10:43:20 (21s before the
    > object I saw) and 28541 at 10:44:08 (27s after what I saw).
    
    Most likely, Ed observed 05004A after a small orbit-raising manoeuvre within the
    past 48 h, intended to allow 05004C to catch up to it. Here are some estimated
    elements:
    
    1 70001U          05056.48078511  .00000011  00000-0  20000-4 0    09
    2 70001  63.4380 105.9315 0124054 180.3166 179.7800 13.39668276    02
    
    1 70002U          05057.45106309  .00000011  00000-0  20000-4 0    05
    2 70002  63.4380 103.4666 0124054 180.3118 179.7849 13.39516403    09
    
    1 70003U          05057.97352045  .00000011  00000-0  20000-4 0    03
    2 70003  63.4380 102.1393 0124054 180.3091 179.7876 13.39175020    09
    
    Description of 2-line elements: http://www.satobs.org/element.html
    
    All of the above were determined by precessing the pre-manoeuvre elements to an
    ascending node, and then adjusting only the mean motion to account for the late
    arrival that Ed observed this morning.
    
    70001 assumes the manoeuvre occurred at the first ascending node after my obs of
    2005 Feb 25 at 10:18 UTC. That defines approximately the smallest change in mean
    motion that would account for your observation this morning.
    
    70002 assumes the manoeuvre occurred 13 revs later than 70001, thus requiring a
    larger change in mean motion that 70001.
    
    70003 assumes the manoeuvre occurred 7 revs later than 70002, thus requiring an
    even larger change in mean motion.
    
    Probably, it is safest to use 70001 for searches, since it defines approximately
    the earliest time of arrival. After 24 h, the 70003 orbit would trail 70001 by
    about 32 s.
    
    Ted Molczan
    
    
    
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