James Hughes was animated as he introduced the planetarium show, "Two Small Pieces of Glass," during a recent private screening in Carnegie Science Center's Buhl Planetarium.

It was as though Mr. Hughes, one of the show's producers, was anticipating a positive response from the audience.

He didn't need to wait long.

As the show opened, viewers felt as though they were hovering around a telescope before zooming into, then through, the long tube and into a starburst scene from our galaxy.

A young girl in the next-to-the-last row yelped with glee. Others gasped at the beautiful vista.

Mr. Hughes smiled broadly beneath the large dome. It was the sort of reaction he wanted, one that emphasized the importance and beauty of the night sky.

"Two Small Pieces of Glass" is a companion to the PBS documentary, "400 Years of the Telescope." The planetarium program produced by Buhl, 'Imiloa Astronomy Center in Hawaii and Interstellar Studios will be distributed to about 750 planetariums around the world. It gives the viewers a taste of what to expect at a public astronomical viewing event called a star party and an idea of the wonders a telescope can reveal.

The planetarium show, documentary and 400years.org Web site are part of the celebration of the International Year of Astronomy in 2009, to commemorate Galileo's first use of the telescope for astronomical purposes four centuries ago. Science centers and astronomy clubs will hold star parties throughout the year so the public can get a clear view of the universe.

"One of the goals of '400 Years of the Telescope' and the system with the planetarium show, the documentary and the Web is to ultimately get people involved in looking through a telescope and then doing their own research and exploration of astronomy," said Kris Koenig, producer, director and a writer of the PBS documentary.

"Astronomy is probably one of the most user-friendly sciences out there. Anybody can be an amateur astronomer; there are no prerequisites. All you have to do is have a desire to look up," he said.

"Two Small Pieces of Glass" is being presented at 2 p.m. daily in the Buhl's Digital Dome. Admission is free with paid admission to Carnegie Science Center.

In case the documentary and planetarium show only whet the appetite for the night sky, there's more associated with the International Year of Astronomy.

WQED-TV's "On Q" program will focus on astronomy at 7:30 p.m. tomorrow. Among those to be featured will be members of the Amateur Astronomers Association of Pittsburgh, a group that holds free star parties for the public at Wagman Observatory in Deer Lakes Park, Frazer, and Mingo Creek Park Observatory in the park in Nottingham, Washington County.

The 400years.org Web site is a great resource for students, teachers and the general public. The site features a newsletter, profiles in astronomy (for example, one can read about Edwin Hubble, the man who discovered the universe is expanding), a teachers' guide with lesson ideas, activities and glossary and links to telescopes of the world. There are links that offer help with discovering the universe, including finding an astronomy club, science center or planetarium near you. Visitors also can download wallpaper for their computers or iPhone.

In some ways, the International Year of Astronomy is more of a preview of coming attractions than a look into telescope history. Discoveries with new telescopes over the next few decades will change the way we see the cosmos.

"We're going to see the beginnings of the Big Bang, we're going to see the first stars born right after the formation of the universe. That's going to be an incredible discovery," Mr. Koenig said. "We have seen what I like to call the sonogram of the birth of the universe … but we haven't seen the actual birth. The day we actually see those first stars is going to be quite exciting and these telescopes that are coming on line will give us that view."