Comet 9P/Tempel 1
Since late 2002, Tempel 1 has been slowly making its way back towards the sun. But during the late summer and fall of 2004, Tempel 1 was on the other side of the sun from the earth and therefore out of view. As the earth continues around in its orbit, Tempel 1 came back into view so that in December, several amateur astronomers were able to get images of the very dim comet.
The image above shows a field of stars and in the upper left, a small animated portion shows a faint dot that moves against the background. In the circle to the right, the individual frames were stacked on the comet (so the stars become trailed) to make it a little easier to find in the image. This is all you can see now because the comet is still far from the sun and basically just a snowball. As it gets closer, the ices on the surface will get heated enough to sublimate (go from solid ice directly to a gas without becoming a liquid first) and form a coma or cloud of dust and gas around the nucleus.
Deep Impact project members hope that many amateurs will participate in its observing programs. The Small Telescope Science Program (STSP) is geared toward technically proficient observers who want to take scientific data. For more casual observers there is the Amateur Observers' Program. Both will have galleries so be sure to visit often throughout the spring and summer of 2005 to check out the latest images of Tempel 1!
Image Date: 2004 Dec 11
CREDIT: Observatorio de Begues 170/José Manteka