[AZ-Observing] Re: 2nd Magnitude Geostationary Satellite
- From: "Jimmy Ray" <jimmy_ray@xxxxxxx>
- To: <az-observing@xxxxxxxxxxxxx>
- Date: Sun, 15 Oct 2006 12:38:40 -0700
INMARSAT 2 F2 was a maritime satellite launched using a Delta launch vehicle
from Cape Canaveral Air Force Base for the International Maritime Satellite
Organization. It operated a total of four INMARSAT-2 satellites. Launched
between 1990-92, they each had a capacity equivalent to about 250 INMARSAT-A
voice circuits.
The spacecraft was built by an international consortium headed by British
Aerospace. Subcontractors included Hughes Aircraft Company, Fokker (The
Netherlands), Matra (France), MBB (Germany), NEC (Japan), and Spar (Canada).
Satellite ground control operations contractors included CLTC (China), CNES
(France), SED (Canada), Telespazio (Italy) and Intelsat.
The INMARSAT-2s were three-axis-stabilized spacecraft based on the Matra/B
Ae Eurostar platform. With a ten-year design life, each satellite has a
1,300 kg launch mass, reducing to an initial 800 kg in orbit. Initial power
rating was 1,200 W.
The communications payload comprised two transponders supporting satellite-
to-mobile (service) links in L-band (1.6GHz uplink, 1.5GHz downlink) and
satellite-to-earth station (feeder) links in C-band (6.4GHz uplink, 3.6GHz
downlink). Effective L-band isotropic radiated power (EIRP) was 39dBW. Each
satellite's global beam covered roughly one-third of the earth's surface.
INMARSAT 2 F2 is now being used as a spare back-up to INMARSAT 3 F4 in the
Atlantic Ocean Region.
-----Original Message-----
From: az-observing-bounce@xxxxxxxxxxxxx
[mailto:az-observing-bounce@xxxxxxxxxxxxx]On Behalf Of Rick Tejera
Sent: Sunday, October 15, 2006 9:58 AM
To: az-observing@xxxxxxxxxxxxx
Subject: [AZ-Observing] Re: 2nd Magnitude Geostationary Satellite
I downloaded the geosat elements from celestrak and loaded them into SkyMap
Pro. Best fit for the time frame is INMARSAT 2-F2. What it is or does I
don't know and since I'm out the door to Church ,, I'll have to satisfy my
curiosity later. Maybe someone else will have the answer by then.
Tom, I'll send you Jpeg of the track when I get home.
Clear Skies
Rick Tejera
President
Editor SACnews
Saguaro Astronomy Club
Phoenix, Arizona
saguaroastro@xxxxxxx
www.saguaroastro.org
-----Original Message-----
From: az-observing-bounce@xxxxxxxxxxxxx
[mailto:az-observing-bounce@xxxxxxxxxxxxx] On Behalf Of Tom Polakis
Sent: Sunday, October 15, 2006 12:20 AM
To: AZ-Observing@xxxxxxxxxxxxx
Subject: [AZ-Observing] 2nd Magnitude Geostationary Satellite
While several of us were observing from Steve and Rosie Dodder's place south
of Maricopa, we observed an interloper 'star' to the northeast of Iota Ceti.
It was distorting the constellation outline, just hanging there at 2nd
magnitude or a bit brighter.
After a few minutes, I put my scope on it, and it became clear that it was a
geostationary satellite, occupying the -5.5 degree declination band. Over
the next ten or fifteen minutes, it slowly faded from naked-eye visibility,
but stayed pretty bright in the scope. We first noticed the satellite at
its brightest at 10:00 p.m. Running the time in desktop planetarium
software, the azimuth works out to be about 150 degrees, or 30 degrees to
the east of the meridian.
What causes an object that is 22,000 miles away to flare to 2nd magnitude?
Has anybody seen a similarly bright rise in brightness of a geostationary
satellite? Who is the local expert on this subject who would be able to
help us identify the satellite?
Tom
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