(no subject)

From: b_gimle@algonet.se
Date: Thu Dec 23 2004 - 06:46:33 EST

  • Next message: b_gimle@algonet.se: "Re: Astra christmas dance and Re: NEOS"

    I detected errors in my computations, and some misconceptions in other replies:
    
    I used "tropical" instead of siderial rate of stars, so the value 
    0.991(twice) in my .CSV data should be replaced by 0.989
    
    I swapped the declinations of the "fake" observations produced, 
    so the corrected obs should be
    2004-12-19 20:50		04:29:03	-7.390	
    2004-12-19 20:54		04:32:57	-7.650	
    (and FOV becomes 0.510 x 0.383)
    
    New elset produced by FIRST.EXE still needed some RAAN adjustment to
    bring it closer to Astra:
    04-854A                       4.0
    1 94854U 04854A   04354.37075419  .00001200  00000-0  24000-3 0 00002
    2 94854 013.5131 244.6514 0000010 000.0000 000.0000 01.00750200 00000
    
    This mail was (is) sent via webb, and HTML removes duplicate blanks, 
    so you must edit the elset before using it.
    
    The fact that it appears to move along an RA great circle in the 
    alt/az reference frame does NOT imply that it is in high-i orbit! 
    Since the southward motion is just 26% of the eastward motion (in the 
    Earth-fixed reference frame) inclination should be near the TLE above.
    
    I have not been able to identify the five or so stars in the 20:48:39 
    frame, or the one traversing 20:49:00-20:50:23 (...?) or the brighter 
    one 20:53:09, so my positions are from the predicted pos of Astra.
    
    The fact that FindSat lists Astra 3A for BOTH my positions is a 
    deficiency of ANY program trying to evaluate a single position in each 
    run. To make a match, the time and crosstrack errors should have 
    similar value (including sign/direction) for all points used.
    
    I prefer to enter the coordinates into SkyMap's DEEPSKY.TXT file, and
    match the tracks that run parallell to the points, at the right speed.
    
    
    ----- Original Message ----- > UNID;;RA;Dec
    
    > 2004-12-19 20:50;;04:29:02;-7.651;;;1280;;;;;0.512
    > 2004-12-19 20:54;;04:32:58;-7.389;;;960;;;;;0.384
    > 
    >04-854A                         3.0
    >1 99854U 04854  A 04354.86927254  .00000000  00000-0  00000-0 0    00
    >2 99854  13.9728 245.0669 0000010   0.0000   0.0000  1.01644026    00
    > 
    
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