Re: Propellant dump and NOSS duo obs

From: Daniel Deak (dan.deak@sympatico.ca)
Date: Thu Feb 03 2005 - 05:50:10 EST

  • Next message: Ted Molczan: "RE: Propellant dump and NOSS duo obs"

    Hi again,
    
    
    I'm not completely awakened, half asleep, I'll try not to forget something...
    
    It was the most spectacular fuel dumnp I've seen since the Delta II second stage 
    in February 2000. Lucille and I got out about 5 minutes before the predicted 
    NOSS pass in Cepheus using this elset :
    MES2                                                   1010 X 1208 km
    1 70999U          05034.37193286  .00000000  00000-0  00000-0 0    08
    2 70999  63.4167 155.0000 0132437 179.7272  98.8000 13.39694040    03
    
    Lucille was checking the sky at 1x while I was seting up my 20x80. As soon as 
    she checked high in the sky, there it was ! The propellant dump had occured 
    before shadow exit and we saw the plume immediately after shadow exit. It was 
    higher in the sky than expected, very bright and greenish. The shape was an 
    elongated triangle pointing downward while traveling toward azimuth 30 deg. Size 
    was already about 7 or 8 degrees. There was a diffuse glow around the triangle 
    having the appearance of wings.
    
    Just below the triangle were two objects. The one near and slightly to the left 
    of the summit of the triangle was the faintest but visible at 1x, I would say 
    mag. 3.5. A bit lower, maybe 1.5 degree, was the second object, the Centaur 
    stage, at mag. 2 with a more orange color. The plume was not connected to the 
    Centaur.
    
    Here are two very approximate positions for the objects, sorry no timing for 
    these two positions as I prefered to enjoy the sight :
    #1 RA 10h30m  dec + 59   uncertainty  5
    #2 RA  3h00m  dec + 88   uncertainty  1.5
    
    Then I got into more serious business and tried to get at least one accurate 
    timing. While chasing the objects with my 20x80, I noticed I could resolve the 
    upper one into two very near objects aligned in the direction of motion. These 
    were definitely the NOSS satellites. The Centaur stage was then about 2 degrees 
    lower and a bit in front of the satellites.
    
    Here is the position obtained for the satellite pair :
    RA 22h27.51m dec +63d58.9m uncertainty of  3 arcmin
    at 9:40:30.9 UTC  1 sec.
    I was not able to get a radio time signal to rely on, so I used the USNO clock 
    sync to check my timing.
    
    The plume continued to grow ans was still easy to see at 1x as it reached the 
    horizon. Its size was then about 15 degrees. My feeling is that the fuel dump 
    was made in the orbital plane perpendicular to the velocity vector and toward space.
    
    I would like to share more details, but I have to get a little sleep before 
    going to work...
    
    It was au unforgetable experience. Thanks Ted for your orbital data !
    
    Dan
    
    
    
    
    -- 
    Daniel Deak
    Webmestre, site Obsat
    L'Avenir, Quebec
    
    COSPAR site 1747 : 45.7275N, 72.3526W, 191 m., UTC-5:00
    
    Site en francais sur les satellites:
    French-language satellite web site : http://www.obsat.com
    
    
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