USA125 etc

From: Greg Roberts (grr@iafrica.com)
Date: Mon Nov 11 2002 - 03:22:59 EST

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    Herewith
    
    (1)  observations obtained of object believed to be USA125.
    (2)  correction to ALEXIS #22638 position 05 November 2002.
    (3)  SDP4 and SGP4 elements for USA125
    
    
    Observations made 06 Nov 2002
    ---------------------------------------
    
    CoSaTrak 1, 85mm f/1.6 lens with 0.003 lux CCD surveillance camera.
    Conditions - good
    
    Cospar Site #0433  Long 18.5129 E, Lat 33.9406 S, altitude 10 metres
    
    Results of an orbit plane search for USA 125 lasting 68 minutes.  A
    possible candidate was spotted and tracked.  Herewith several positions
    obtained during the 10 minute manual track:
    
    23945 96 038A   0433 G 20021106203830600 17 15 0208160-002506 39 S+084 05
    23945 96 038A   0433 G 20021106203833100 17 15 0208411-003156 39 S+084 05
    23945 96 038A   0433 G 20021106203922800 17 15 0216128-025533 39 S+084 05
    23945 96 038A   0433 G 20021106203951300 17 15 0220569-042131 39 S+083 05
    23945 96 038A   0433 G 20021106204054500 17 15 0232199-074845 39 S+082 05
    23945 96 038A   0433 G 20021106204128900 17 15 0239090-094952 39 S+081 05
    23945 96 038A   0433 G 20021106204212200 17 15 0248356-122917 39 S+080 05
    23945 96 038A   0433 G 20021106204421400 17 15 0323084-211659 39 I+065 05
    23945 96 038A   0433 G 20021106204521100 17 15 0343170-253901 39 S+072 05
    23945 96 038A   0433 G 20021106204704100 17 15 0425418-331120 39 S+086 05
    23945 96 038A   0433 G 20021106204748100 17 15 0447190-361234 39 S+087 05
    
    Notes:
    
    (1) The satellite was running approximately 14 minutes late on the expected
        search orbit for Teds object 71001U.
    
    (2) During the pass the satellite was steady at about magnitude 8 except
        for an approximate arc of 1 degree at culmination when the satellite
        increased rather dramatically in brightness to about magnitude +04
        and gave a few flashes. After this it reverted to its magnitude of
        about +8
    
    (3) Very shortly after the last position given I lost the satellite-it
        became too faint for my system
    
    (4) I have given a fair number of positions as it is possible that one
        or more may be a little "off" - I was trying to measure video images
        very close to the limit of my system and may have got the wrong pixel/s.
        If more positions are required I am sure I can scratch up more.
    
    (5) My thanks to Ted for the search orbit, Willie Koorts for his fantastic
        COSATRAK tracking program and to Thierry Marais for his orbit scan
        program XWAIT.
    
        Without these a 68 minute plane search would be a pain in the ***.
        As it is I found my concentration decreasing as the search progressed
        and my eyes getting all screwed up from staring at the video monitor.
    
    
    Observations made 09 Nov 2002
    --------------------------------------
    
    CoSaTrak 1, 85mm f/1.6 lens with 0.003 lux CCD surveillance camera.
    Conditions - fair - moon present
    
    Cospar Site #0433  Long 18.5129 E, Lat 33.9406 S, altitude 10 metres
    
    23945 96 038A   0433 F 20021109202718860 17 15 0239056-095020 39 S+075 05
    23945 96 038A   0433 F 20021109202816900 17 15 0252037-132606 39 S+074 05
    23945 96 038A   0433 F 20021109202943300 17 15 0314490-191540 39 I+060 05
    23945 96 038A   0433 F 20021109203031300 17 15 0329436-224159 39 S+068 05
    23945 96 038A   0433 F 20021109203113600 17 15 0344248-254755 39 S+072 05
    23945 96 038A   0433 F 20021109203137300 17 15 0353189-273329 39 S+073 05
    23945 96 038A   0433 F 20021109203245900 17 15 0422066-323031 39 S+081 05
    
    Notes:
    
    (1) Last position may not be as accurate as the first 6-last view I had
        before computer crashed so I tried to get a position to give as long
        an arc as possible.
    
    (2) Next time I track I will track on the predictions instead of doing
        a plane search and then having to track manually once the object
        acquired. The elements were "spot on" so a prediction track would
        have made things somewhat easier.
    
    (3) I still dont know why the pc crashed.
    
    (4) I propose to track again evening of 12 November, weather permitting
        and also attempt to recover 95066A which is now visible here.
    
    
    Alexis:
    ~~~~~~~~
    As is not unusual for me, I made a slight error in the position reported
    for ALEXIS on the 5th November,2002.  The correct details are
    
    19h24m42.4s UT  RA 18h54m33.5s  Dec -35d 23' 51"
    
    Originally I had a declination of -33 degrees -- looks like I cannot even
    transcribe my own writing!   Thanks to David Brierley for spotting this.
    
    Cheers
    Greg
    
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    
    (3) I attach a message from Thierry Marais to Ted and myself which is self
        explanatory:
    
    
    Dear Ted,
    
    The following elset is an attempt of direct conversion of your SGP4
    fit to SDP4.
    Compatibility with obs. not checked.
    I got 3km rms difference between two orbit models. It may be better
    over time, for progs. automatically switching to sdp4 due to mean motion.
    
    Wishes,
    Thierry.
    
    USA 125          0.0  0.0  0.0  5.7 v
    1 23945U 96038A   02313.88997685  .00000000  00000-0  00000-0 0    90
    2 23945  63.6134 193.3636 6918633 271.3232  17.0369  2.00652438    01
    
    > Ted's SGP4 fit
    >USA 125          0.0  0.0  0.0  5.7 v
    >1 23945U 96038A   02313.88997685  .00000000  00000-0  00000-0 0    01
    >2 23945  63.6190 193.3656 6917012 271.2979  17.0173  2.00658750    08
    
    
    
    
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