Overview

You begin asteroid hunting by taking two or three images of the same field during the course of an hour or so. With appropriate software you then align the images and alternately display them in rapid succession on a computer monitor — the cyberworld equivalent of a photographic blink comparator. Anything moving in the field stands out like the proverbial sore thumb. The once-tedious task of measuring precise positions is now replaced by a few minutes clicking a computer mouse.

Just as impressive is the speed with which objects can be identified as new. Via the Internet or a direct modem connection to computers at the Minor Planet Center in Cambridge, Massachusetts, in less than a minute you can get a listing of all known asteroids and comets in any selected region of the sky. If a moving object doesn't turn up on the list, there's a good chance it's new.

All that remains is to make a confirming sighting on a second night (multiple sightings on one night don't qualify). Then you put the positions you've measured in a standard format and send them electronically to the Minor Planet Center. Usually within a day (sometimes within hours) an e-mail reply will acknowledge the observations and, if the object is indeed new, assign a designation.

It's worth mentioning that all this work can be done with commercially available hardware and software, and the whole process goes amazingly fast. Some evenings I've sat down at the computer keyboard to image, blink, find an object, measure its position, check if it is known, and prepare the data for electronic submission (assuming confirmation on a second night) without ever getting up from the chair.

As easy as all this sounds, there are some basic protocols for recording and measuring the positions of faint asteroids, whether known or newly discovered. Let's consider them in the order in which they occur.