Re: Flashing Sphere, Magnitudes in Calsky

From: Mike McCants (
Date: Sun Oct 26 2008 - 21:15:51 UTC

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    Neal Robichaux posted:
    >(a) How can a sphere flash?  Obs from (5) passes of Vanguard 2 (59001A /
    >00011) in Feb & Mar '08 revealed an approx. 5-sec flash period.  This
    >from a 20" dia. sphere with a handful of antennae?
    Objects with antennae often flash.  The assumption is that sunlight
    is reflecting along the length of the antennae.
    Arnold Barmettler posted:
    >CalSky is using Mike McCants data file for dimensions and standard
    >magnitudes containing more than 2000 satellites.
    The quicksat.mag file has many more magnitudes if you add 1.5 to its
    standard magnitude to compensate for the difference in definitions.
    But it does not have 00900 (64-63C).  For object 1520 (similar) the
    observed standard magnitude would be 9.5.
    >The default magnitude for
    >other 10,000 pieces is set to mag 5 (1000 km range, 50% illuminated)
    Anything with a standard magnitude 6.5 or brighter ought to be in the
    McCants data file that you are using.  So perhaps you should use a
    fainter default (except for recently-launched objects).
    >or mag 9 (for debris).
    Or you could use the mean RCS value and compute an intrinsic magnitude from that.
    Mike McCants
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