Last year, when Russ Waugh, director of the Howard B. Owens Science Center planetarium, was deciding on a topic for this season's public program, the world was in the throes of Y2K hysteria.

Seeking to build on the date-related brouhaha, the astronomer decided to create "Y1K," a multimedia program for children and adults, which debuted Friday at the Lanham planetarium.

The presentation examines the onset of the last millennium, when the populace was consumed by a phenomenon that captured public imagination as much as the Y2K bug: an unusually dazzling star that the naked eye could see dashing across the sky day and night.

"We look at something that was witnessed 1,000 years ago and see what we understand about it now at the turn of the millennium," Waugh said of the program.

During the presentation, an astronomer provides historical background about the period when the star appeared. Then slides and video are used to demonstrate what happened.

After a flash in the sky in 1054, Chinese observers took careful notes, describing a shimmering star near the constellation Taurus. At the time, observers had no idea what they were looking at. But nearly a millennium later, that is no longer the case.

"We think we know today what [the flash] was," Waugh said. "It was a supernova, a cloud of expanding gas or a neutron star."

The crab-shaped astral body is still visible today: It's called the Crab nebula, and it is one of the most studied objects in the sky.

After a 20-minute multimedia planetarium presentation about the Crab nebula, the astronomer presides over a question-and-answer session and gives visitors a planetarium tour of the night sky.

The Y1K program is one of three original public programs the center conducts when it opens to the public on the second Friday of each month. The rest of the time, the planetarium hosts Prince George's County school groups. The 22-year-old science center is just blocks from the Goddard Space Flight Center in Greenbelt.

See "Y1K" at 7:30 p.m. Friday. The program will repeat Feb. 11, March 10, April 14, May 12 and June 9 at the Howard B. Owens Science Center, 9601 Greenbelt Rd., Lanham. Admission is $4 for adults, $2 for students and seniors. For more information, call 301-918-8750.