Obs 06 July 2005

From: Greg Roberts (grr@iafrica.com)
Date: Thu Jul 07 2005 - 13:05:13 EDT

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    Observations 06 Jul 2005:
    -------------------------------
    
    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 145mm focal length f/2.5 lens. I normally integrate for
    96 frames for geostationary objects which is equivalent to an
    exposure of 1.92 seconds per image. Successive images are then
    stacked on top of one another 200 times, giving an effective total
    exposure of 200*1.92 seconds = 384 seconds. Stars show up as trailed
    objects whilst geostationary satellites appear as dots if the
    inclination is close to 0 degrees or else as slightly trailed
    objects, the length of the trail depending on the inclination and
    altitude.
    
    Site 0433 : Longitude 18.51294 deg East, Latitude  33.94058 deg S,
    Elevation 10 metres - situated in Pinelands (Cape Town), South Africa
    
    
    
    
    For CLASSFD.TLE:
    ------------------------
    
    27168 02 001A   0433 G 20050706193641300 56 15 1443480+031841 39  +095 05
    27712 03 012B   0433 G 20050706193641300 56 15 1443473+031352 39  +095 05
    27938 03 041B   0433 G 20050706192911400 56 15 1744443+084244 39  +090 05
    90013 03 564A   0433 G 20050706193020800 56 15 1739346-021303 39  +075 05
    90016 03 766A   0433 G 20050706173628500 56 15 1339345+041050 39  +105 05
    90031 05 546A   0433 G 20050706181346800 56 15 1814149+044424 39  +125 05
    90034 05 592A   0433 G 20050706193338800 56 15 1630272+040014 39  +110 05
    90035 05 625A   0433 G 20050706192422400 56 15 1844302+051359 39  +090 05
    90036 05 629A   0433 G 20050706181224500 56 15 1824391+032440 39  +125 05
    90037 05 638A   0433 G 20050706185901900 56 15 1901542-082854 39  +090 05
    90038 05 638B   0433 G 20050706182949300 56 15 1838550+023401 39  +110 05
    
    Stray geostationaries measured:
    -------------------------------------
    
    RADUGA 2
    09416 76 092A   0433 G 20050706190755000 56 15 1846310-102431 39  +100 05
    GORIZONT 2
    11440 79 062A   0433 G 20050706190755000 56 15 1853056-103924 39  +105 05
    INTELSAT 904
    27380 02 007A   0433 G 20050706192422400 56 15 1845216+051446 39  +095 05
    
    Stray LEO objects measured :
    ----------------------------------
    
    COSMOS 1275 Debri (rocket?)
    12654 81 053J   0433 G 20050706163754100 56 15 0945407-345001 39
    SL-12 R/B(2)
    15334 84 106B   0433 G 20050706162824700 56 15 1034355-401855 39  +060 05
    ROCSAT 1
    25616 99 002A   0433 G 20050706172252700 56 15 0822572-183646 39  +030 05
    
    
    
    Notes:
    ------
    
    (1) First hour or so was spent carrying out an orbital plane scan.
        Although I still have to go through the DVD recording slowly
        nothing unknown was seen.
    
    (2) COSMOS 1275 rocket produced a spectacular flashing display -
        for those who like looking at flashing satellites this one is
        worthwhile watching.
    
    (3) MILSTAR 6 CNr is now passing MILSTAR 5 - they were close together
        and about equal in magnitude.
    
    (4) #90035 and Intelsat 904 still continue their dancing together but
        tonight was the maximum distance I have seen them apart.
    
    (5) I made a boo-boo after I completed the orbital plane scan when I
        changed the integration time for images from 48 ( which I use
        for LEO satellites ) to 128 frames instead of my usual 96 frames.
    
        Whilst the images appeared okay on the monitor in "real-time" mode
        they turned out very "washed out"- ie low contrast when frames
        (exposures) were added (stacked) together the next day. It would seem
        that with 128 frame integration the background sky noise level becomes
        too high and reduces the signal to noise ratio of the satellite to
        the background sky. It would thereafore appear that I should get
        better results using short exposures and stacking of numerous frames
        rather than using long exposures with fewer frames.
    
        Guess its similar to the chemistry question - is it better to do
        one or too large washings of a precipitate or numerous small washings
        - ( I know the  answer - I was a chemist several decades ago before
        becoming a professional astronomer).
    
    
    
    Cheers
    Greg
    
    
    
    
    
    
    
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