For some at the open house the attraction was scientific interest, although most others seemed more intent on enjoying the novelty of doing something they had always wanted to do without worrying about the possibility of going blind.

For whatever reason, a crowd of people lined up against the wall in a small, circular room at the U.S. Naval Observatory yesterday to stare directly into the light of the Sun.

The gigantic telescope, more than 20 feet long, with a 12-inch-wide lens and a special filter enabling viewers to peer at the Sun, was a popular attraction at the observatory's annual open house.

"I thought it was really interesting," said Tami McNeil after her look at the Sun, which appeared glowing and deep red through the lens. "It was neat just because I was looking at the Sun."

Others were less impressed. "I didn't see a thing," confessed 11-year-old Randolph Dowell. The Sun had ducked under a cloud moments before the boy stepped to the viewing stand after his 20-minute wait.

Many of the more than 1,500 visitors to the observatory, located on a wooded hill off Massachusetts Avenue NW, said their interest in astronomy was spurred by publicity over Halley's Comet, which will swing near the Earth late this year for the first time since 1910.

"I've always been interested in stargazing," said Jane Redicker. "I have gotten especially interested hearing about the comet."

Although Redicker may join one of the many clubs that have been formed to follow the path of Halley's Comet with telescopes, she said she won't be among those spending several thousand dollars to join ocean cruises in the southern hemisphere to view the comet.

Just as well. Dr. Gart Westerhaut, scientific director of the observatory, said the comet "will be a big dud" for those without sophisticated telescopic equipment.

Although some of the original writings of Isaac Newton and Galileo are stored at the observatory, along with telescopes more than 100 years old, Westerhaut bristles at the suggestion that the observatory is nothing more than an interesting museum.

Employes at the observatory are constantly tracking the positions of stars and measuring the Earth's rotation -- information that remains crucial to operating modern navigating equipment. For example, when using high-tech satellites, Westerhaut said, "It's not like if you know where you are within a mile or so, that's all right."

Also open for viewing was the observatory's Master Clock, an enormous bank of computers that constantly monitor and average the time given by 24 highly accurate "atomic clocks" at different places on the grounds of the observatory, said spokeswoman Gail S. Cleere. The Master Clock keeps official time for the United States.

For some people, the Master Clock was the only functional exhibit at the observatory. Said Matthew Lawskin, at exactly 2:17 and 40 seconds yesterday afternoon: "The only reason I came here was to set my watch. I'm leaving now."