Optical 04 Dec 2008 Part 1

From: Greg Roberts (grr@telkomsa.net)
Date: Fri Dec 05 2008 - 13:37:41 UTC

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    Observations 04 Dec 2008 Part 1
    ----------------------------------------
    
    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.
    Generally the DSI Pro II camera will be used for high altitude
    slow moving objects. Tests seem to indicate that its sensitivity
    is comparable to the MINTRON ( possibly better) but as its not
    possible (?) to time stamp to better than 1 second accuracy the
    time resolution is not good enough for LEO objects.
    
    Meade DSI Pro II Monochrome CCD camera without filters.
    using integration times of 20 sec min to 60 seconds maximum
    depending on brightness of sky in particular area.No image
    processing done but dark field applied.
    Used with 200mm focal length f/2.8 Nikkon telephoto lens,
    field of view 1.88 x 1.40 degrees. Can get to magnitude 13
    or so in less than 20 seconds exposure.
    Exposure time to nearest second inserted into image FITS header
    from PC clock which is automatically checked every minute against
    GPS signal.
    
    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:
    ----------------- 
    21805 91 080B   0433 G 20081204204822000 56 15 2245545-050224 39  +110 05
    21805 91 080B   0433 G 20081204205653000 56 15 2254329-044912 39  +100 05
    32287 07 054A   0433 G 20081204202051000 56 15 0203346+081402 39  +105 05
    32287 07 054A   0433 G 20081204203456000 56 15 0217431+080655 39  +105 05
    32287 07 054A   0433 G 20081204204035000 56 15 0223225+080346 39  +105 05
    
    
    OBSERVATIONS Unknown #91128 - Night 2 of observing it:
    ----------------------------------------------------------
    91128 05 338GEO 0433 G 20081204184823000 56 15 0043116+043311 39  +100 05
    91128 05 338GEO 0433 G 20081204185306000 56 15 0047192+044312 39  +100 05
    91128 05 338GEO 0433 G 20081204190546000 56 15 0058301+050806 39  +100 05
    91128 05 338GEO 0433 G 20081204191028000 56 15 0102412+051724 39  +100 05
    91128 05 338GEO 0433 G 20081204192830000 56 15 0118379+055400 39  +100 05
    91128 05 338GEO 0433 G 20081204194720000 56 15 0135173+063253 39  +100 05
    91128 05 338GEO 0433 G 20081204200934000 56 15 0155018+071650 39  +095 05
    91128 05 338GEO 0433 G 20081204202051000 56 15 0205045+073913 39  +095 05
    91128 05 338GEO 0433 G 20081204203456000 56 15 0217375+080718 39  +095 05
    91128 05 338GEO 0433 G 20081204204035000 56 15 0222433+081812 39  +095 05
    91128 05 338GEO 0433 G 20081204211431000 56 15 0253129+092202 39  +095 05
    91128 05 338GEO 0433 G 20081204211913000 56 15 0257292+093045 39  +095 05
    91128 05 338GEO 0433 G 20081204212355000 56 15 0301417+093929 39  +095 05
    91128 05 338GEO 0433 G 20081204213319000 56 15 0310158+095542 39  +095 05
    91128 05 338GEO 0433 G 20081204214243000 56 15 0318507+101215 39  +090 05
    91128 05 338GEO 0433 G 20081204214821000 56 15 0323590+102207 39  +090 05
    
    Notes:
    --------
    
    (1) Concentrated mainly on tracking 91128 in order to better define the
        orbit. Very similar track to previous nights observations.
    
    (2) Monitored DSP-F16 (#21805) to see at which phase angle it became
    visible. If DSP satellites are to west of observer in evening they are
    very faint and its only when their phase angle is less than a particular
    value does it brighten up. At phase angle = 93 degrees I suspected I could
    see it, about magnitude +13. At phase angle = 92 degrees the satellite
    started brightening and at phase angle = 90 degrees it was doing obvious
    flashes at about magnitude +8.5. After passing 90 degrees it started to
    fade again but was still brighter than magnitude +10.5 at phase angle = 87.5
    degrees when I stopped watching , so it looks like the "magic value" is
    about 92 degrees and at lower values the satellite is then brighter than
    about 12th magnitude.
    
    (3) Will report strays observed tomorrow - Ive had enough of satellites
        to last me the rest of the day .
    
    Cheers
    Greg
    
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