Re: Iridflare on I-Z photo? / satellite

From: Björn Gimle (b_gimle@algonet.se)
Date: Sun Aug 25 2002 - 15:52:01 EDT

  • Next message: Christian Steyaert: "Re: Iridflare on I-Z photo? / satellite"

    Christian,
    If it wasn't solved yet, your thanks were premature ?
    
    On my first check, I probably didn't use an elset file near the date given.
    When I found time to check the stereo effect, and do the triangulation, I
    eventually found the solution - but it could easily be done without all these
    computations and image transformations !
    
    The satellite is
    Cosmos 1220      6.0  0.0  0.0  4.9 v   20       631 x 505 km
    1 12054U 80089A   02096.43010465  .00012357  00000-0  92703-3 0  3319
    2 12054  64.9844  88.6764 0090561 151.7847 208.8222 14.99688456 69742
    recent elset:
    1 12054U 80089A   02228.52406784  .00011170  00000-0  79756-3 0  7194
    2 12054  64.9800  34.7907 0076663  90.6632 270.3349 15.02500593 89572
    
    At the track center: 565 km height, 1574 km range, predicted pass of pi (20) Cas
    20:15:12 UTC, going right (NorthEast), track length 13s on Comet2.jpg.
    
    I first computed two points at equal distance and parallell directions from the
    two observing locations, put these points in SkyMap .pnt (and/or .trj!) files to
    have the baseline size and direction displayed in SkyMap.
    
    Then I rotated and rescaled the two images and the SkyMap plot to same size,
    with a horizontal baseline and parallax. Unfortunately, the true stereo effect
    is too large to be admired. I then measured the parallax, and compared it to the
    one predicted from a known height/range.
    
    If you are interested in the original or processed images, or my computations, I
    will mail the files (or put them on my/some homepage).
    
    
    -- bjorn.gimle@tietotech.se (office)                         --
    -- b_gimle@algonet.se (home)  http://www.algonet.se/~b_gimle --
    -- COSPAR 5919, MALMA,    59.2576 N, 18.6172 E, 23 m         --
    -- COSPAR 5918, HAMMARBY, 59.2985 N, 18.1045 E, 44 m         --
    
    ----- Original Message -----
    ...
    > Got various interesting reactions from , but the true problem wasn't solved
    yet.
    > ...
    > Mons en Montois does not have Lat  48 deg 48' N, Long 3 deg 14' E, as
    indicated to me, but 48.48 deg N,  3.14 deg E...
    >
    > Now the triangulation is quite good, but the exact time is unknown. An
    > appearance during the first half of the exposure gives the better
    > triangulation results.
    >
    > This must come from a quite bright object, as it is more than 1000 km away:
    >
    > 8 April 2002, between 20h13m and 20h40m UT
    > 5 deg W, 57 deg N  (+- a few degrees in Long and Lat)
    > height between 250 and 350 km
    > duration of the 'flare' between 7 and 10 seconds
    >
    >
    > Thanks for identifying it!
    ...
    
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