Roughly 500 geostationary satellites are currently placed in a static orbit (as viewed by a ground-based observer) about our planet at an
altitude ranging from 500 to 40,000 kilometers. The closest satellites orbitting the planet are believed to be spy satellites whereas most
distant are the geostationary group of satellites with an instrinsic magnitude of 11 or greater. As a result, due to their distance and faint
magnitude, geosats may be classified as the DSO's of the satellite world. At their high altitude not only can they virtually view the complete
globe below them but they also have the unique characteristic of having their orbital speed closely match the rotational speed of the earth
and, as such, give the impression to a ground-based observer of being stationary above the planet. These satellites have a wide range of
applications and functions and include remote sensing (Meteosat, GOES-East and GOES-West, GMS etc) and such telecommunication functions as
direct broadcast voice and video communications as well as live television coverage (Astra, Hot Bird, Telstar etc) by virtue of the fact they
can beam their signal from a "fixed" point in space relative to a ground source.
Note: Arabsat 5C was launched from Kourou, French Guiana using an Ariane 5 ECA rocket on September 21, 2011, weighs 4.630 tons and features 26 C-band and 10 Ka-band transponders with an expected lifetime of 15 years. Arabsat 5C has a footprint which covers the Middle East and Africa with broadcast transmissions related to television, telephone and business communications, Internet and various other interactive services.
Note: The first image below represents a single one-minute exposure whereas the second image below is the sum of the fifteen one-minute exposures captured and which reveals some very slight motion for the four Astra satellites during the approximate 20-minute span and which quite often is characteristic of geosats (ex. due to inclination).
Sep 21, 2011
Nov 02, 2012
22:31 - 22:48 UT+2
AP 305/f3.8 Riccardi-Honders
AP 1200GTO GEM
SBIG LRGB filters
1.21" per pixel