Phobos-Grunt: rotating or stable?

From: Ted Molczan (
Date: Fri Nov 11 2011 - 00:48:15 UTC

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    As Simone Corbellini reported, experts seeking to restore command and control of Phobos-Grunt are interested to know
    whether it is stable or rotating (tumbling):
    Brad Young observed it on Nov 10, about 11:33 UTC, and reported it steady in brightness, which indicates little or no
    There has not been a formal request for observations by the public, but additional observations using the various
    methods available to us may be of value.
    Due to its low altitude, the object is only visible during narrow ranges of latitude. 
    Northern hemisphere observers between roughly 20 N and 40 N have morning twilight visibility.
    Southern hemisphere observers between roughly 7 S and 25 S have evening twilight visibility.
    The best observing conditions occur near the middle of the above ranges.
    Useful observations could take several forms:
    1. Still camera exposures, showing the satellite's trail as a streak. If it is rotating, then there will be regular
    variations in the brightness of the streak.
    2. Motion video. Follow the object for at least several minutes, to reveal whether there are regular variations.
    3. Visual timing of maxima or minima (if any). This is the method that Brad used this morning. Instructions, including
    standard reporting format are here:
    Ted Molczan
    Seesat-l mailing list

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