Optical 18 Dec 2013

From: Greg Roberts (grr@telkomsa.net)
Date: Thu Dec 19 2013 - 14:35:10 UTC

  • Next message: Greg Roberts: "Re: Optical 17 Dec 2013"

    Observations 18 Dec 2013 Part 1
    ------------------------------------
    
    Cosatrak 1 (Computerised satellite Tracking System).
    
    FLI ML8300M CCD camera with mechanical shutter + Trimble GPS
    
    Used with 85mm focal length f/4.0 Nikon lens.
    Field of view 12.0 x 9.0 degrees.
    Images processed automatically using APEX.
    
    Site 0433 : Longitude 18.51294 deg East, Latitude -33.94058 deg,
    Elevation 10 metres-situated in Pinelands (Cape Town),South Africa
    
    FOR CLASSIFIED.TLE:
    ---------------------------
    28888 05 042A   0433 P 20131218193201298 16 15 0904504-373950 38
    28888 05 042A   0433 P 20131218193354179 16 25 0743538-203158 28
    28888 05 042A   0433 P 20131218193434526 16 25 0718334-122456 28
    28888 05 042A   0433 P 20131218193514867 16 15 0655441-035533 29
    28888 05 042A   0433 P 20131218210900386 16 15 2140427-632656 88
    28888 05 042A   0433 P 20131218210936636 16 15 2240599-563806 58
    28888 05 042A   0433 P 20131218211019052 16 15 2330059-453255 58
    28888 05 042A   0433 P 20131218211055310 16 15 2359085-341001 58
    28888 05 042A   0433 P 20131218211155751 16 15 0030179-144453 38
    28888 05 042A   0433 P 20131218211201798 16 15 0032315-125913 89
    28888 05 042A   0433 P 20131218211207842 16 15 0034421-111237 48
    28888 05 042A   0433 P 20131218211213885 16 15 0036427-093021 48
    28888 05 042A   0433 P 20131218211232005 16 15 0042248-042605 38
    39232 13 043A   0433 P 20131218195653835 16 15 0854178-362307 68
    39232 13 043A   0433 P 20131218195736197 16 15 0823575-303114 58
    39232 13 043A   0433 P 20131218195818470 16 15 0754091-225725 48
    39232 13 043A   0433 P 20131218195906834 16 15 0723576-131304 58
    39232 13 043A   0433 P 20131218195918927 16 15 0716552-103810 68
    39232 13 043A   0433 P 20131218213352744 16 15 2306415-574930 48
    39232 13 043A   0433 P 20131218213422957 16 15 2340318-505423 48
    39232 13 043A   0433 P 20131218213435048 16 15 2351523-474308 48
    39232 13 043A   0433 P 20131218213559684 16 15 0043005-231234 38
    39232 13 043A   0433 P 20131218213641994 16 15 0057260-112445 48
    
    
    NOTES:
    ----------
    
    (1) Herewith observations of USA 186 and USA 245 for 18th December.
    
    (2) APEX does not like such a wide field of view as sometimes it
        can contain 30000 or more stars down to magnitude +12 - not that
        that many could be seen under full moon conditions but APEX
        loads all stars in the field of view down to magnitude +12 then
        selects less than a hundred or so to do the plate solution and
        produces a position and residuals.
        With my usual observing set-up APEX solves an image in under 20
        seconds - with this wide field of view it can take up to 4 or 5
        minutes! ( PC is 3.3 Ghz)
        With such a large field of view I dont think the positional
        accuracy is that great.
        However APEX disagrees with me and gives residuals between
        1 and 6 arc seconds and state that its about 0.1 of a pixel.
        The image scale was 51.8 arc sec/pixel.
        Timing accuracy is better than 50 milliseconds - the camera
        automatically rejects observations that have a timing error
        greater than 50 milliseconds.
    
        Mike/Ted - let me know if the residuals you get indicate that
        it is not a good idea to use such a large field of view.APEX
        is intended for geostationary satellites so I am using it for a
        purpose it was not intended for - eg LEO sats - it seems to do
        the job but maybe Mike and Ted are being too diplomatic and not
        complaining about obvious positional errors.
    
    (3) I still have more positions to report of other classified sats
        which I will do tomorrow as I am now too tired - too many nights
        of too little sleep recently!
    
    Cheers
    Greg
    
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