RE: 4641 OTV2-1.

From: Ted Molczan (ssl3molcz@rogers.com)
Date: Mon Aug 22 2011 - 13:05:15 UTC

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    Alberto Rango wrote:
    
    > Today, 22 August, I had a morning session to try to find OTV2-1
    > 
    > which was expected to exit from eclipse at 02 09 42 sec 198/123.
    
    Mike McCants' latest elements yield eclipse exit ~2.5 min earlier, and passage through the FOV in which you observed the
    reported objects near 02:07:26 UTC.
    
    1 37375U 11010A   11221.86811651  .00000000  00000-0  00000-0 0    0
    2 37375  42.7878  48.8373 0010000  52.9256 307.0738 15.78803625    0
    
    > There are two candidates:
    > 
    > A sat,  steady +6.5,  02h09m40s.14   05h35m.4  -0623       +/- 5  eq. 1950
    
    This was one of the NOSS 3-5 pair. I am not certain which one. The position is between a pair of stars oriented roughly
    vertically in an alt-az FOV. If the top star is A, then it was ~0.6 from A to B. The closest match is 11014B, but one of
    the reference stars would change. Star A would become B, and the magnitude 2.7 star above it would be the new A. That
    would yield this position, about 0.03 deg from the predicted track, and 1.5 s early, relative the epoch 11209.09056014
    elements: 
    
    37391 11 014B   4641 G 20110822020940140 17 24 0533685-060199 18 S+065 05
    
    A case might also be made for 11014A, involving a different pair of nearby stars. Star A would be the mag 6.6 near
    05:34, -07:01 (2000.0) and B would be the mag 6.8 immediately below (in alt-az FOV). The resulting position is about
    0.18 deg from the predicted track, and 0.7 s late, relative the epoch 11209.09064832 elements:
    
    37386 11 014A   4641 G 20110822020940140 17 24 0532074-070973 87 S+065 05
    
    Some track error is to be expected, given that perturbations not modelled by SGP4 are causing a gradual reduction in
    eccentricity, but it would be very great, since the elevation was only 14 deg.
    
    When last observed, these objects were still drifting to their operational location relative the NOSS constellation.
    Once they reach it, they will reduce their period by ~0.7 s to synchronize with the constellation, which will cause them
    to arrive about ~10 s per day early, relative the pre-manoeuvre elements. 
    
    > Another sat, steady + 7,  02h27m39s.92   05h33m.5  -0539.4   +/-1   eq. 1950
    
    This is the first rocket body of GPS 2-06. IOD position:
    
    20453 90 008B   4641 G 20110822022739920 17 24 0533500-053940 18 S+070 05
    
    Ted Molczan
    
    
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