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Geosynchronous satellites are in an orbit that make them appear to be in the same location in the sky relative to the ground. If you were to attach a telescope to a fixed mount so that it never moves while it's aimed at one of these satellites, it would always be close to the center of the field. This is the way satellite television works, the antenna only has to be aimed during the initial installation.
This doesn't work for the stars and other objects far out in the sky and they appear to move as the Earth spins on its axis. For this photograph of the Orion nebula, the telescope was guided so that the stars were in a fixed location relative to the telescope's view. This way they don't make star trails in the photograph.
I took a few photographs in succession so that I could pick out the best one or maybe even combine some of them to reduce electronic noise from the camera (which looks like film grain). When I was looking them over, I noticed that three of them had short streaks that lined up parallel to the equator but move across the sky. I realized that I managed to capture a geosynchronous satellite in these three photographs. They orbit over the Earth's equator, which from the view of my observatory, passes through the Orion nebula. I used the satellite plotting capability of my sky charting software to learn that I photographed a K-Band communication satellite named GSTAR 4.
I took this photograph with my Canon EOS 20D digital camera attached to Mira, my home-made Lurie-Houghton 9.8" f/4.63 telescope, which has a focal length of 1154mm. The telescope was attached to a Losmandy G-11 equatorial mount in the JaZ Observatory at my home in central Arizona the evening of 15 January 2005. This photograph was made by combining the three images to show the passage of the satellite over time. The exposure of each image was 8 seconds at f/4.63 with the camera set for ISO 1600 in RAW mode. The field of view in this photograph is about 1.05 degrees wide by 0.74 degrees high. Adobe Photoshop CS was used to perform the RAW conversion and image processing. Photograph by Rick Scott
Updated: 15 May 2005