Optical 25 Jan 2013

From: Greg Roberts (grr@telkomsa.net)
Date: Sat Jan 26 2013 - 13:48:38 UTC

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    Observations 25 JAN 2013
    ------------------------------------
    
    Cosatrak 1 (Computerised satellite Tracking System).
    
    WATEC 902H2 SUPREME (EA)video camera set on maximum
    sensitivity-at expense of S/N (signal to noise ratio),
    and locked on exposure 1/60th second. Recorded as NTSC
    (555 lines) at 29.97 frames/sec and used with ~ 100mm
    focal length f/2.8 lens, field of view approx3.9 x 2.9
    degrees.
    
    Images processed and measured manually.
    
    Site 0433 : Longitude 18.51294 deg East, Latitude -33.94058 deg,
    Elevation 10 metres-situated in Pinelands (Cape Town),South Africa
    
    FOR CLASSFD.TLE:
    -------------------------
    24680 96 072A   0433 P 20130125193729011 55 15 1316179-482711 19
    24680 96 072A   0433 P 20130125193742665 55 15 1303199-474828 19
    24680 96 072A   0433 P 20130125193749227 55 15 1256425-472554 19
    24680 96 072A   0433 P 20130125193759212 55 15 1246233-464238 19
    24680 96 072A   0433 P 20130125193803884 55 15 1241072-461849 19
    28888 05 042A   0433 P 20130125192516787 55 15 1117150-274050 19
    28888 05 042A   0433 P 20130125192524505 55 15 1115469-272440 19
    28888 05 042A   0433 P 20130125192532474 55 15 1108547-255432 19
    28888 05 042A   0433 P 20130125192604745 55 15 1053392-214640 19
    28888 05 042A   0433 P 20130125192630808 55 15 1039426-182915 19
    28888 05 042A   0433 P 20130125192633573 55 15 1038268-180703 19
    31702 07 027B   0433 P 20130125185205609 55 15 2315088-080742 19
    31702 07 027B   0433 P 20130125185346465 55 15 2300091-255457 19
    31702 07 027B   0433 P 20130125185453360 55 15 2238544-395118 19
    
    NORTH KOREAN ROCKET:
    -------------------------
    39027 12 072B   0433 P 20130125191556674 55 15 1138133-405434 19  +075 05
    39027 12 072B   0433 P 20130125191705303 55 15 1032130-291343 19  +055 05
    39027 12 072B   0433 P 20130125191744652 55 15 0955245-190133 19  +065 05
    
    NOTES:
    --------
    (1) I made a slight boo-boo. Several weeks ago I checked on visibility
        of the North Korean satellite and rocket and found that I lost
        visibility in mid Feb- but I did not look close enough. I actually
        loose useful visibility now - I was hoping to get a good try at
        determining the spin period of the satellite after full moon had
        passed, but that is not to be and I suspect that for my purpose
        observations of KMS 3-2 for spin rate are over. When initially
        observed it was a relatively easy satellite at most elevations as it
        produced flashes. However these flashes seem to have got fainter and
        not so pronounced. The spin rate has decreased slightly - maybe this
        has made flashes less prominent but I suspect it could be the way
        in which the satellite is orientated with respect to the sun-is this
        possible? When last seen relatively easily the satellite only started
        producing bright enough flashes just before culmination and the
        satellite went into earths shadow shortly thereafter so effectively
        only had "visibility" for less than a minute.
        In order to try and get a spin rate as accurately as possible it was
        necessary to use as short an exposure as possible - no use doing a
        1 or 2 second "integration" when trying to measure a spin rate of
        about 4 seconds to a tenth second or better. The WATEC is regarded
        as the most sensitive video camera available at a reasonable price.
        It was necessary to fix the exposure at 1/60th second so the problem
        boiled down to recording a satellite as faint as 8 or 9th magnitude
        in 1/60th second - I did not find this easy and impossible in bright
        moonlight. So it looks like this experiment is over.
        The satellite is now only in sunlight for observable passes over
        very high northern latitudes. I found the satellite to be mostly
        fainter than 9th magnitude with flashes to about mag +6 or +7 when
        at best but usually around mag +7.5 to +8. I once had two successive
        flashes to very easy naked eye - perhaps mag +2 or so and seen
        through fairly thick cirrus.This video was uploaded to YouTube.
    
    (2) Suspect observed last observable pass of USA 129 for my summer season
        and it looks like USA 186 is not far behind.
    
    Cheers
    Greg
    
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