Re: unid flashing geosynch

From: Mike McCants (mmccants@io.com)
Date: Mon Sep 20 2004 - 12:00:44 EDT

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    Ed Cannon posted:
    
    >Last night looking for Gorizont 29, I saw an unid flashing
    >geosynch.  The brightest maxima were +4.5.  The flash
    >period was about 42 or a multiple of that.
    
    Based on positional observations from Sept. 20 04:43 to 05:52 UT
    I have derived the following circular orbit:
    
    Unknown 040920
    1 90022U 04764A   04264.19896990 0.00000000  00000-0  00000-0 0    04
    2 90022   9.7600  77.0000 0001000 223.0000   0.0000  1.06382000    09
    
    This is quite low for a circular graveyard orbit.  Alternatives are
    that the object was near perigee with a non-zero eccentricity:
    
    1 90022U 04764A   04264.19898147 0.00000000  00000-0  00000-0 0    00
    2 90022   9.7900  77.0000 0100000 223.0000   0.0000  1.04182000    08
    
    1 90022U 04764A   04264.19894675 0.00000000  00000-0  00000-0 0    02
    2 90022   9.8100  77.0000 0150000 223.0000   0.0000  1.02982000    02
    
    1 90022U 04764A   04264.19899305 0.00000000  00000-0  00000-0 0    07
    2 90022   9.8300  77.0000 0200000 223.0000   0.0000  1.01982000    09
    
    There are many other solutions with appropriate values of eccentricity,
    argument of perigee, and mean motion.
    
    I can even generate a synchronous orbit with a high enough eccentricity:
    
    1 90022U 04764A   04264.19903934 0.00000000  00000-0  00000-0 0    01
    2 90022   9.8400  77.0000 0290000 223.0000   0.0000  1.00270000    08
    
    But I am puzzled by an inclination of 10 degrees with a node at 77 degrees.
    I cannot generate an elset like this using any reasonable starting elset
    by applying lunar and solar perturbations.  A typical orbit with a 10
    degree inclination has its node about 43 degrees.  A typical orbit with
    a node near 77 degrees has an inclination of only 5 degrees.  Because of the
    place in the orbit where the observations were made, the inclination
    and node are reasonably accurate.
    
    The brightest flashes last night were about RA 19Hr 15Mn, Dec -12 degrees.
    The observed pattern was 3 bright flashes over 85 seconds followed by
    a gap when 4 flashes were not seen, followed by another 3 bright flashes
    about 210 seconds after the preceding set.  Later, only flashes to magnitude
    9 or 10 were seen in the 8 inch.
    
    Mike McCants
    Austin, TX
    
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