Hunting Asteroids From Your Backyard
A convergence of technology has opened the realm of asteroid discovery to virtually any backyard observer.
You can discover an asteroid tonight. Digital technology and the CCD revolution have given amateurs the ability to do it.
At first glance, these may not seem to be profound statements. After all, you might discover a nova, supernova, or a comet too; amateurs have proven they can do these things. But in the case of asteroids there's a major difference. If you decide to search for them on any clear, dark night, you can be virtually guaranteed of success in your quest, whereas with the other three the chance is rather slim.
That's the conclusion I reached in early 1995 after accidentally discovering eight asteroids with a CCD-equipped 11-inch telescope in the course of following known objects during the previous 12 months. A new object had turned up in one out of six CCD fields covering 12 by 16 arcminutes each. This was small-number statistics for sure, but I reasoned it would be an easy evening's project to shoot six random fields and find something new.
In October 1995 I decided to put my idea to the test, and on the night of the 12th I imaged five overlapping fields near the ecliptic in Pisces. Covering a patch of sky only 18 arcminutes wide by 50 high, I was prepared to blame failure on the nearly 90 percent illuminated Moon nearby. To my delight, however, three moving objects appeared in the very first field! One turned out to be a known asteroid somewhat off its predicted position, but the other two were new and I received credit for their discovery.
Lucky night? Not really. By the close of the year I had searched on another eight evenings, usually by imaging several fields adjacent to those containing known objects, and examined a total area of about nine square degrees near the ecliptic. On all but one night I was successful, chalking up an additional 21 confirmed discoveries 18th magnitude or brighter.
A convergence of digital technology that includes CCDs, computer software, e-mail communication, and CD-ROM star catalogs has opened the realm of asteroid discovery to virtually any backyard observer. Here's what you need to know.