FOR RELEASE: 10:00 AM PDT, June 10, 1998
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Staring patiently at the sky from its owner's back yard, a high-tech camera recently recorded the six-millionth stellar measurement in The Amateur Sky Survey. "The operator didn't celebrate the milestone," explains Michael Richmond of the Rochester Institute of Technology, who is presenting a poster at the American Astronomical Society meeting in San Diego, CA. "In fact, he was probably asleep at the time."
The Survey (TASS for short) is run by a volunteer force of amateur astronomers, with help from a few professionals. Members scattered across the US employ ordinary camera lenses attached to sophisticated electronic detectors -- built and distributed for free by TASS founder Tom Droege, an engineer at Fermilab -- to scan the stars in a narrow strip around the sky. Since the cameras are fully automatic, their operators are able to sleep at night -- a necessity for people with day jobs. TASS workers reduce the images with home-grown software on their own PCs, then send the results to a central database via the Internet.
Over the past two years, the survey has collected over six million measurements. "We look repeatedly at stars in the same area of the sky," reports Richmond, "so we've accumulated an average of about 35 data points for each one. Combining them yields improved values for each star's position and brightness, as well as allowing us to check for variability." TASS has discovered evidence for changes in the brightness of over 50 stars previously thought to be constant, and has added many data points to known variables.
Survey activity takes place over the Internet: members exchange E-mail, transfer data, and keep in touch with their own Web page: http://www.tass-survey.org. The group has no funding, no management structure, no by-laws, and no boss. It holds discussions by E-mail in which every person is encouraged to speak, and members decide what to do on their own. Chris Albertson, of Redondo Beach, CA, applied his programming skills to create a repository for the group's observations. "For the past year, I've been running Chris' database on my computer," says Richmond, "but this meeting in San Diego is the first time I've ever met him." Amateurs Glenn Gombert of Dayton, OH, and Mike Gutzwiller of nearby Cincinnati, not only gather hundreds of megabytes of images with their cameras, but are working hard to improve data reduction techniques. The group gets expert advice on photometry from Arne Henden, an astronomer at the US Naval Observatory in Flagstaff, AZ.
Survey results are freely available to anyone, with no strings attached. Margaret Konopacki, a student at Dallastown (PA) High School, approached TASS members Marty Pittinger, Nick Beser and Bernie Kluga of the Applied Physics Lab at Johns Hopkins University, with ideas for a science fair project. They supplied her with images taken by the local TASS camera, and she determined how best to search visually through them for moving objects. Her project, "The Online Search for the Killer Comet," won several prizes at her school, an award from the Association of Women Geophysicists, and First Place in its category in the Pennsylvania state competition.
Richmond sums up TASS as a humble but worthy effort. "Our catalog will support the work of other astronomers by providing reference stars for future observations. For example, if a satellite detects a gamma-ray burst in our survey area, we may be able to place limits on the brightness of an optical counterpart. We'll fill gaps in some existing surveys, discover lots of new variable stars, and act as a link between very bright and very faint sources. And, although it's very unlikely, we may accidentally stumble across that Killer Comet."