5918 (5919) obs

From: ComHem (b.gimle@comhem.se)
Date: Tue Mar 27 2007 - 11:06:09 EDT

  • Next message: Ted Molczan: "USA 193 elements"

    Sunday evening I got three points on USA 186 at site 5919, but left my notes
    there :-(
    Yesterday at 5918, disturbed by light fog illuminated by the city and the
    moon, I got only one, when it passed .6 degrees from Alcor+Mizar. Above in
    the FOV at that time a faster satellite confused me, and while trying to
    decide which one to follow, I lost both.
    Three seconds before that obs USA 186 should have passed in a tight group of
    stars of +8 mag, but they were not visible in the light conditions I had,
    though I had brought my 10*50.
    28888 05 042A   5918 F 20070326184821370 27 25 1322593+552905 48 S
    The format is described at
    http://www.satobs.org/position/IODformat.html
    
    Looking at a graph of Mean Motions for 26934 and 28888 in 2006 (+2007 for 
    28888) it seems that -0.012 reboosts of 28888 occurred at about 3½ month 
    intervals, so the next one should be late April (and may be a large one, 
    since MM should be 14.78).
    However, 28888 drag has recently been lower than normal, (and 26934 is 
    unseen since 06301.75) and previous intervals were prolonged by a small 
    correction around Aug.05 - and probably Nov.-Dec, so this time is quite 
    uncertain.
    About midway between reboosts, the time (or longitude) separation of 
    26934/28888 passes reach a minimum, when their mean motions are equal.
    If 26934 has had lower average drag as well, this occasion has already 
    passed, otherwise it is about time now.
    Anyway, the separations change slowly after this time, so now should be a 
    good time to recover 26934.
    On Aug.1 26934 was 2h09m behind, and 14.0 degrees East of 28888 (daylight 
    45N)
     I intend to drive to site 5919, and unless fog from the Baltic Sea stops 
    me, use these search elsets:
    USA 161 +2:09 16.0 E at 45N SB
    1 26934U 01044A   07086.67668586  .00003570  00000-0  64943-4 0    12
    2 26934  98.0060 197.9904 0464678 113.1117 251.9764 14.77855550 22109
    USA 161 +2:19 13.5 E at 45N SB
    1 26934U 01044A   07086.68368586  .00003570  00000-0  64943-4 0    12
    2 26934  98.0060 197.9904 0464678 113.1117 251.9764 14.77555550 22109
    USA 161 +2:29  11.0 E at 45N SB
    1 26934U 01044A   07086.69068586  .00003570  00000-0  64943-4 0    12
    2 26934  98.0060 197.9904 0464678 113.1117 251.9764 14.77255550 22109
    
    -- Björn Gimle                                            --
    -- COSPAR 5918 WGS84,  +18.10127 (E), +59.29813 (N), 44 m --
    -- COSPAR 5919, MALMA, +18.6206  (E), +59.2615  (N), 33 m --
    -- COSPAR 5920, FRUVIK,+18.4820  (E), +59.3260  (N), 11 m --
    
    
    
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