Re: Weird observation not solved, Geosat fllares

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Hi!
I want to thank Paulo Cacella and Alcir Carra for posting their very
interesting observations.
It seems that  they both observed specular reflections on the solar panels
of these satellites, nothing else than
for example a Superbird flash.
Obviously, geosats brighten before and after eclipses because of the
favourable phase angle, but to observe
flares, the geometry has to be very special. Modern three-axis-stabilized
geostationary satellites
have an attitude in which one panel is pointing south, the other north. The
rotation axis of the panels
is accurately aligned to the north/south celestial pole. This allows the
panels to be steered in a way that
they always point to the celestial equator and the same right ascension as
the sun.
With this orientation of the panels, a southern hemisphere observer can see
flares a few days after the spring
or before the autumn equinox. (reversed for northern hemisphere). Possible
are only  satellites close
 to eastern horizon after sunset (before eclipse, Alcir Carra case) and
close to the western horizon before sunrise
 (after eclipse). (How I wish to include a drawing!!).
Anyway, since the spring geometry might still be favourable, southern
observers should still try to observe these
flashes (or how should we call this?) on any controlled satellite close to
the horizon.
 South America should look for the ASTRA cluster as well! (For Alcirs
location at altitude of about ten degrees!)
I am looking forward to the autumn equinox!

Rainer

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