USA 39 recovered

From: Matson, Robert (
Date: Wed Apr 12 2000 - 11:57:43 PDT

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    Hi All,
    After nearly a year of searching, hampered by coastal clouds,
    periodic moonlight, work schedule, and on and on, I finally
    recovered USA 39 (1989-046A, #20046) Monday night (April 10
    local, April 11 UT) using 8 x 56 binocs under clear, but
    slightly moon-polluted skies.  Last April, Mike McCants and
    I lost it sometime between April 6th and April 18th.  (Mike
    saw it the 6th; neither of us could find it the 18th).  After
    doing some snooping around the LANL site, I knew that 1989-046A
    started moving west on April 9th.  By the 11th it had already
    moved about 5 degrees in longitude, explaining why neither of
    us could find it.
    The satellite's flashes are not visible for long each night in
    binoculars -- I only saw the +7 mag flashes intermittently for
    about 3 minutes, though I may have missed the beginning.  I was
    only able to record one solid reference point, and a second
    less accurate one.
    The following search orbit should be sufficient to acquire
    the satellite for the next several days (from California, Hawaii,
    Arizona, Nevada, New Mexico, and western Texas).  I have not
    calculated correct checksums -- I just used the ones from a
    prior elset.  The inclination is an extrapolation based on
    solar-lunar effects after one year.  I have not changed the
    eccentricity, argument of perigee or mean anomaly from last
    year's elset -- I've simply changed the epoch and RAAN to
    match my observation, and changed the mean motion to get a
    stable satellite longitude.
    USA 39
    1 20066U          00102.10150000  .00000000  00000-0  00000+0 0    01
    2 20066   5.0040  55.5000 0080000 225.1993 150.0035  1.00272000    09
    I had hoped to refine the orbit with observations Tuesday night,
    but coastal clouds intervened at the critical time.  Flashes
    Monday night were visible from 22:20 - 22:23 PDT (or 11 April
    5:20 - 5:23 UT).  No flashes were visible Tuesday night from
    21:35 - 22:10 PDT (12 April 4:35 - 5:10) -- limiting magnitude
    about +7.8.  If the clouds had held off another 15 minutes, I
    think I would have seen it.
    Hopefully someone with darker skies, a telescope, or both can
    pick this up soon so that a better TLE can be posted.
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