Report of fuel dump obs

From: Daniel Deak (dan.deak@sympatico.ca)
Date: Tue Dec 11 2007 - 02:26:55 UTC

  • Next message: Daniel Deak: "RE: more images of Centaur fuel dump"

    Good evening,
    
    (Second try to send this message, the first one bounced at 02:00 UTC)
    
    Here is a more detailled report.
    
    Lucille and I waited for the fuel dump cloud with the unaided eye and
    binoculars starting at 23:35 UTC. I first spotted the cloud in 12x60 binos
    at around 23:43 low to the southwest. A band of clouds prevented observation
    before that. It was then at about 15 deg. elevation (very rough estimate).
    It was yellowish in color and looked like a V tail inclined to the left. In
    binoculars no satellite could be seen because it was lost in the cloud
    spike.
    
    I attempted positional obs but no reference stars were easily seen. It
    definitely slowed as it raised above the horizon as opposed to usual
    satellite passes. A few minutes later, the Centaur stage could be seen apart
    from the gaseous tail. I then geared up for positional obs while Lucille
    followed the object for its optical behavior. Her tracking proved very
    useful to spot two other flashing objects nearby.
    
    I saw these flashing objects too. They flashed quite bright at maybe mag 3
    to 5 in an irregular way but they were all sharp flashes, very rapid ones.
    The two flashing objects looekd above the Centaur stage but one was a bit in
    front of it. Separation between the stage and the farthest object was about
    35 arc minutes before culmination. I don't know what they are but they could
    be covers or other objects ejected form the satellite. No other steady
    object was seen around the rocket. The rocket itself was around mag 6 at
    first then it faded slowly but steadily because of its altitude rise. I
    stopped my observation at around 00:30 UTC because I could not see the
    satellite anymore at mag 9.5.
    
    The gas cloud had its usual shape and grew up to about 3 degrees in size
    before fading. It looked a lot like the dump from the Atlas 2AS launch in
    February 2005 for which I made two sketches :
    http://www.obsat.com/images/AC206dump1.jpg
    http://www.obsat.com/images/AC206dump2.jpg
    Tonight's obs was something between the two images but inclined to the left.
    
    The timing for the following data points was done using Internet tine on the
    USNO as a reference. I figured a 1.5 second accuracy because of that.
    79001 07 060B   1747 G 20071211000020300 28 25 2214160+331360 68 S
    79001 07 060B   1747 G 20071211000620700 28 25 2243590+414914 68 S
    79001 07 060B   1747 G 20071211001305700 28 25 2317730+491435 68 S
    79001 07 060B   1747 G 20071211002412900 28 25 0017490+573517 68 S+090 05
    
    
    Daniel Deak
    Webmestre, site Obsat
    Pompier, municipalite de L'Avenir, Quebec
     
    COSPAR site 1747 : 45.7275N, 72.3526W, 191 m., UTC-4:00
     
    Site en francais sur les satellites:
    French-language satellite web site : http://www.obsat.com
    
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