Optical 12 Jan 2010

From: Greg Roberts (grr@telkomsa.net)
Date: Wed Jan 13 2010 - 09:06:11 UTC

  • Next message: Russell Eberst: "2010JAN12.OBS"

    Observations 12 Jan 2010
    ----------------------------
    
    Cosatrak 1 (Computerised satellite Tracking System).
    Camera mount now carries two systems that can be operated
    together as two totally different sytems and computers used.
    
    (1)Meade DSI Pro II Monochrome CCD camera without filters.
    using integration times of 5 sec min to 25 seconds maximum
    depending on brightness of sky in particular area.No image
    processing done, but some done automatically in the auto reduction
    software.
    
    Used with 4 inch SKYWATCHER refractor- model 1025 - fitted with home
    made focal reducer to give an f/2.56 system. Image scale is 6.56 arc
    sec/pixel and field of view 84.8 x 63.2 arc minutes. Shows 15th
    magnitude stars in real time with reasonably good conditions.
    
    Exposure time to nearest second inserted into image FITS header
    from PC clock which is automatically checked every minute against
    GPS signal.
    
    (2)Video - MINTRON surveillance camera+100mm f/2.8 telephoto lens-
    variable exposure depending on sky background - typically 1 to 2.5
    seconds. Field of view 3.3 deg x 2.6 degrees. Under reasonable
    conditions can see stars down to mag +12.
    
    Site 0433 : Longitude 18.51294 deg East, Latitude -33.94058 deg,
    Elevation 10 metres-situated in Pinelands (Cape Town),South Africa
    
    FOR CLASSFD.TLE:
    -------------------
    observed CCD camera and reduced in APEX
    29242 06 024C   0433 F 20100112201042000 16 15 0244434+285829 28
    29242 06 024C   0433 F 20100112201240000 16 15 0247318+273909 28
    
    Video observation - manual processing
    21809 91 076E   0433 F 20100112211818900 56 15 0039260-634937 39  +079 05
    21809 91 076E   0433 F 20100112211824500 56 15 0035540-644745 39  +079 05
    
    Video observation - possibly USA 186
    28888 05 042A   0433 F 20100112211112100 56 15 0059200-725844 39  +060 05
    28888 05 042A   0433 F 20100112211114000 56 15 0103360-723616 39  +055 05
    28888 05 042A   0433 F 20100112211115800 56 15 0102260-711405 39  +040 05
    28888 05 042A   0433 F 20100112211117700 56 15 0113030-714336 39  +050 05
    28888 05 042A   0433 F 20100112211119600 56 15 0117350-711445 39  +055 05
    
    Video observation - Unknown
    99999 99 999A   0433 F 20100112214855700 56 15 0028230-432952 39  +115 05
    99999 99 999A   0433 F 20100112214942700 56 15 0028310-424043 39  +110 05
    99999 99 999A   0433 F 20100112215016500 56 15 0028340-420433 39  +115 05
    99999 99 999A   0433 F 20100112215041000 56 15 0028370-414102 39  +115 05
    99999 99 999A   0433 F 20100112215145900 56 15 0028450-403416 39  +115 05
    99999 99 999A   0433 F 20100112215245100 56 15 0028520-393508 39  +110 05
    99999 99 999A   0433 F 20100112215309500 56 15 0028530-391126 39  +080 05
    
    Notes:
    --------
    (1) Intention for evenings observing was to do a plane scan for USA 186
    which is currently "lost". Did a one orbit scan and two unknowns found.
    
    The first one is believed to be USA 186 running just over 29 minutes
    late on last element set. A little puzzled by optical behaviour as quite
    variable during the few seconds it took to cross field of view.
    
    A rough orbit determination gives i = 97 deg, period 100.6m, h =786km
    assumming a circular orbit which USA 186 is not.
    
    (2)The unknown object is also puzzling me. Offhand I cannot recall a
    high altitude object in this kind of orbit. It appeared variable, ranging
    from +8 ( seen once for about 4 seconds) but mainly around mag +11 to
    +12 but varying in brightness. A rough orbit determination gives
    i = 101.0 degrees, height 14000 kms, period 482 minutes. Again a
    circular orbit is assumed.
    
    The chances of locating this object again are remote.
    
    (3) USA 137 - Trumpet 4 - #29242 appeared steady during the short spell
    observed but as range was about 10000 kms probably not worth much. Will
    attempt to detect variability closer to perigee. Observations this session
    were curtailed as I had to start the USA186 plane scan.
    
    Cheers
    Greg
    
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