Optical 20 June 2007

From: Greg Roberts (grr@telkomsa.net)
Date: Thu Jun 21 2007 - 04:52:33 EDT

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    Observations 20 June 2007:
    -------------------------------
    
    Cosatrak 1 (Computerised satellite Tracking System).
    MINTRON low light level CCD surveillance camera (0.005 lux typical
    in non integration mode) and 0.00005 lux in STARLIGHT mode with 128
    frame integration.
    
    Used with 25mm focal length f/1.4 lens,integrating for 128 frames
    which is equivalent to an exposure of 2.52 seconds per image.
    
    Site 0433 : Longitude 18.51294 deg East, Latitude  33.94058 deg S,
    Elevation 10 metres - situated in Pinelands (Cape Town), South Africa
    
    
    For Classified.tle:
    -----------------------
    
    19460 88 078A   0433 G 20070620164601400 56 15 1106150+160837 39  +047 05
    19460 88 078A   0433 G 20070620164617200 56 15 1108584+200902 39  +056 05
    19460 88 078A   0433 G 20070620164630200 56 15 1111010+230357 39  +058 05
    26473 00 047A   0433 G 20070620164853900 56 15 1139246+251309 39  +045 05
    26473 00 047A   0433 G 20070620164911900 56 15 1149420+211514 39  +042 05
    26473 00 047A   0433 G 20070620164927500 56 15 1159310+171602 39  +036 05
    
    
    Notes:
    ---------
    
    (1) Final night testing 25mm lens - conclusion is that it is NOT
        suitable for positional work as the scale is too large. In
        the case of both satellites above the 2.52 second integration
        barely produced a trail and I think that in this case SATREC-
        program used to determine the positions- takes the centre of the
        light "blop" so would introduce an error of maybe as much as
        one second (or more) in time. For positional work one needs
        considerably better angular resolution. SATREC said positional
        accuracy was around 38 arc seconds but I dont believe it. I also
        think that Lacrosse 4 was somewhat brighter than the program
        reported and in addition the lens had some vignetting at the
        edge. This lens will in future only be used for looking for lost
        satellites and other things, eg meteor showers.
    
    (2) Observed another 38 satellites but dont think its worthwhile
        taking the time to measure/report  etc - ie Im lazy.
    
    Cheers
    Greg
    
    
    
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