The Laser Christmas show arrives at the Hansen Planetarium from a company called Audio Visual Imagineering in Virginia. It's an unexciting-looking item. Just a tape, like something you'd plug into a VCR.

Selections from the "Nutcracker" Suite and Christmas carols are on the tape - sung by Bruce Springsteen, Bing Crosby, Brenda Lee, the Mormon Tabernacle Choir and Elvis - along with two laser pictures to illustrate each section of each song.The laser images are simple. They might consist of a green dot, for example, and a line drawing of Madonna and Child. Or a yellow square and a Christmas tree. Nothing too special.

But when Mike Mills, the planetarium's laser operator, flashes the images on the dome, and the music swells, and he begins to manipulate the nobs and dials on his laser control panel - the lights begin to dance.

The voice of a grandpa says to his grandson,

"What I remember best about Christmas when I was young are the lights and the music." It's true. Somehow the dancing lights and old-time carols evoke the feelings of childhood Christmases, leaving each person in the audience to fill in his or her own memories.

And children in the audience are called on to use their imaginations as well. Why else would they laugh at a small red dot hopping across the dome, unless they were endowing it with living characteristics?

What is the best way to describe a laser light show, this 1980s kind of art/entertainment form? Is it a cross between ballet and a Disney cartoon? A blend of "Fantasia" and the Fourth of July?

"Each show is live," explains Mills, as he sends the laser pictures shooting. "I have a pretty good idea of what I am going to do with the images, but I listen to the audience reaction and key off them. If they are `ahhing' I know I'll keep that effect the next night, maybe play off it again later in the show."

He wiggles 50 different knobs and gets an infinite variety of effects. The ghosts of color - then back into a simple line again.

Mills uses two lasers, a Krypton and an Argon. Mysterious as those names sound, their effects are even more mysterious.

Laser light is seen only when it hits something. The Krypton laser reflects off the dome. The Argon laser can be seen only when the fog machine is on. Like a sunbeam, it shoots through rolling clouds.

"The images that get the `oohs' and `ahhs' come not only through lasers but through our Digistar computer projector," explains Doug Lowe, the planetarium's public relations director.

During the planetarium's traditional star shows the Digistar gives the audience the same three-dimensional effect. It can make you feel as if you are in a rocket ship moving through space to visit a certain star or planet. You can also feel as if you are whirling, turning, dropping. "We could give you vertigo if we wanted to," says Lowe, smiling. "But we haven't had anyone get sick yet."

"Laser Christmas" continues through December 31 at the Hansen Planetarium at 6 and 8 p.m. Monday through Saturday and also at 1 and 3 p.m. on Saturday. The planetarium also shows the traditional "Star of Bethlehem" program at 7 p.m. with extra performances Saturday at 11 a.m. and 2 p.m. and Sunday at 2 p.m.

The cost is $3 for adults, $2 for children and seniors. By coming at 6 or 7 p.m. you can see both shows for $5 or $3. For more information, call 538-2098.