"Balcewicz, Joseph F" wrote:
> Has anyone reported seeing a GPS (Navstar) satellite with the unaided eye?
>
Not that I know of.
> What magnitude might they be?
>
Wayne Hughes wrote:
>I figure magnitude 10-12.
The ISI Consulting technical archive for a 1999 launch
http://www.isi-consulting.com/tech/1999/gpsii3.html
says that the GPS payload measures 94 inches long and 91 inches in
diameter. (2.4 meters long and 2.3 meters in diameter)
This should give an RCS of about 5 or 6.
I have intrinsic magnitudes (full phase at 1000Km) of 4.5 or 5.0 for
the few that I have seen. This translates into an observed magnitude
of about 11.0 to 11.5. Typically I used a 10 inch reflector at about
100 power (about 8 years ago).
However, ISI Consulting also says "with solar panels 180 degrees apart".
I have observed flashes from some GPS payloads (perhaps as bright as
magitude 9).
>Satellite situation report says they have radar cross sections of 10-100,
But my "median" values range from 2 to 50 and the median of the medians
is about 5 or 6. So I suspect that RCS values for these objects (and many
other high objects) are sometimes much too high.
>rule of thumb of a magnitude of 7.3 for a satellite with an rcs of 1 at
My thumb says 6.3, but I always see objects brighter than they
really are. :-)
>but it did get the CSL-04 99057AU fragment
>at 1100 km and rcs=0.18 last night.
Wow, I'm jealous. :-)
>I noticed in the SSR that geosynch
>Galaxy 5 has a rcs of 760 (suggesting magnitude 7-8) and Glonass 36,
>the Russian GPS counterpart, has a rcs of 555. Could these be right?
No way. :-)
Mike McCants
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This archive was generated by hypermail 2b29 : Wed May 31 2000 - 12:38:11 PDT