RE: Phobos-Grunt

From: Ted Molczan (
Date: Fri Nov 11 2011 - 12:05:59 UTC

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    Mike Murphy wrote:
    >  I just observed a pass of Phobos-Grunt and the Zenit second stage.  The
    > rocket body was tumbling slowly, and the probe itself appeared to be very
    > steady as it passed.  I did not get good timing information, but the probe
    > was definitely steady.  I saw no other objects along the track the probe
    > followed.  Both objects appeared to be on time with the ephemerides from
    > the latest element sets.
    >  I used the latest element sets from Space-Track (Set 013 for the probe and
    > Set 011 for the rocket body) and TS Kelso's "Trakstar" program to generate
    > the pointing angles.
    > Location: near Dayton, Ohio at 39.8735, -84.1197 and  286 meters elevation.
    Mike, thank you for your observation.
    To save interested readers time I will add a few details about your pass, which was on Nov 11, in morning twilight. The
    s/c (11065A / 37872) was predicted to exit eclipse at about 11:32:02 UTC, at azimuth 258 deg, elevation 13 deg. About 1
    min later, it culminated at 17 deg. At about 11:34:57 UTC, it passed below 10 deg elevation near azimuth 180 deg.
    Phase-angle was excellent, and predicted maximum brightness was magnitude 4, +/- 1, based on s/c dimensions. 
    I know that you did not make timings, but can you recall the approximate duration of your longest continuous period of
    observation of the spacecraft during the pass?
    Ted Molczan
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