Sometimes it's better to be lucky than good. On January 23, 1999, a satellite-based instrument called the Burst and Transient Source Experiment (BATSE) detected a bright flash of gamma rays coming from the constellation Bo¿tes. For years, astronomers had caught sight of such gamma-ray bursts several times a week in every part of the sky [see "Gamma-Ray Bursts," by Gerald J. Fishman and Dieter H. Hartmann; Scientific American, July 1997]. But precious little was known about these sources of incredible energy--how do they form and from where do they originate?--because they are so fleeting. They rarely shine longer than a few minutes (some exist for only a tiny fraction of a second), providing little time for astronomers to bring a variety of instruments to bear. Indeed, even though that night's event was quite bright and lasted almost two minutes, BATSE could only localize the source to a disk on the sky about four full moons wide.

Image: HUBBLE SPACE TELESCOPE, Space Telescope Science Institute THE SKY is filled with mysterious events, such as this gamma-ray burst detected on January 23, 1999. A network of amateur astronomers could help reveal the secrets of such incredibly powerful--but maddeningly brief--blasts of energy.

Enter Lady Luck. At the moment the burst went off, another satellite called Beppo-SAX just happened to be imaging the same section of sky, using a wide-field camera for x-rays (radiation of somewhat lower frequency than gamma rays). Within six hours of receiving a detection alert from BATSE via e-mail, scientists had fixed the precise position of a bright x-ray source that was within the BATSE-identified region but that had not been there before.

Astronomers were also able to obtain optical images of the gamma-ray burst. Just 20 seconds after the first alert had sounded, a robotic optical telescope in Los Alamos, N.M., had zeroed in with four wide-field cameras. After other researchers had identified the burst's precise position, the Los Alamos group discovered that its early images had captured a bright (9th magnitude) but rapidly fading star at that exact location.

The next night the mighty Keck II, the 10-meter monster telescope that sits atop the Mauna Kea volcano in Hawaii, swung into action. With its huge light-gathering surface, it measured the object's redshift and determined that the gamma-ray burst had originated halfway across the universe.

That's when champagne corks started popping. For something so distant to shine so intensely in our sky, it must be incredibly bright at its source. In fact, whatever produced the gamma rays had, for a while at least, been the brightest object ever identified. Without a doubt, astronomers had made a major discovery. And now they aim to get amateurs in on the fun.

Why amateurs? Because the BATSE team members know that had the Beppo-SAX satellite been looking elsewhere that night, astronomers never would have been able to direct ground-based telescopes to measure the object's magnitude and distance. And even then it took precious hours to fix a position of the rapidly changing object.

A better system would consist of numerous observers looking inside the BATSE-identified region within minutes of the event's detection. With enough people, chances are that someone would quickly find the new object and report in so that other observations could be set in motion. Thus, the BATSE team has wanted to create an international network of both professionals and amateurs who will be on standby to help when BATSE detects a gamma-ray burst

Graph: JOHNNY JOHNSON, NASA INTENSE BUT EPHEMERAL energy is a characteristic of gamma-ray bursts, making it difficult to pinpoint their exact locations. The event that was detected on January 23, 1999, lasted less than two minutes.

Amateur involvement is not as far-fetched as it may sound. Thousands of hobbyists own research-quality telescopes. But even instruments with mirrors as small as 25 centimeters could participate. (Such devices could either be bought for about $700 or fashioned, albeit with considerable time and effort, for less than $100.) And these days many amateur telescopes are equipped with sensitive charge-coupled-device (CCD) cameras that can capture an electronic image of a star field. A personal computer could then process this information in real time to identify new objects. Some of the more expensive telescopes are even automated: they can receive instructions via the Internet and take images anywhere in the sky--without an observer even having to be there. Clearly, the amateur community is ready to be a vital partner in uncovering the secrets of these strange sources of gamma-ray energy.

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