Amateur Asteroid Discoveries, Panning for Astro-Gold

by Sean Walker

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Asteroid 2008 UZ drifted across the field during an evening imaging run. Click on the image to see an animation of the object's movement.

Paul Mortfield

Despite the growing number of professional surveys searching for near-Earth asteroids, amateurs still can bag a few new discoveries.

Amateur Paul Mortfield spends time with every imaging run he completes blinking each exposure and comparing the results to older survey images to see if something new appeared.

The effort has paid off. Mortfield has been credited with the discovery of two new asteroids, officially designated 2008 UY and 2008 UZ. Both objects are roughly 20th magnitude, and barely noticeable above the background signal in his exposures.

"Using a 16-inch telescope at f/8.9, I managed to capture these faint objects slowly drifting across my CCD images while taking 15-minute exposures," Mortfield explains. "They were only noticeable when I stretched each frame and blinked the results. I suppose if this stuff was easy, everyone would be doing it!"

Mortfield details a few simple steps that any imager can perform to search for asteroids, variable stars, and supernovae, as well as other scientifically useful information, hidden in the images we capture every clear night. Read about his experiences in Sky & Telescope's December issue, on newsstands now.