Students looking to take a break from homework tonight will be able to step outside and look up at the sky to see a glowing orange moon in a lunar eclipse that will not happen again until 2015.

Flandrau Science Center and the Tucson Amateur Astronomy Association will hold a free public viewing of the lunar eclipse and other celestial objects at the Tucson Convention Center tonight.

Michael Magee, director of the Flandrau Planetarium, said lunar eclipses happen every few years, but he is especially excited about this eclipse because of its duration and the time it will occur. The next lunar eclipse visible in the Tucson sky will be on Feb. 20, 2008; however, an eclipse as long as tonight's will not occur again until 2015.

"When an event like this happens, which is rare, we like to bring it to the public," Magee said.

Magee said the moon will enter into the eclipse at about 5:30 p.m. He said the darkest part, or the totality of the eclipse, will happen at approximately 7:28 p.m. and will last until 8:43 p.m.

The eclipse will be visible for all of North America and much of the Western Hemisphere, though the time it occurs in Tucson makes it convenient for many people to view, Magee said.

During an eclipse, the full moon passes into the shadow of the earth. For an eclipse to occur, Earth must be precisely aligned between the sun and the moon.

"A big chunk of the people in the world will get to see it," Magee said. "Timing and viewing make it very convenient for everyone. It will be ideally situated in its time and position in the sky."

Magee said because of homecoming events the eclipse viewing will be downtown and not on the overcrowded UA mall where public viewings are usually held.

He said the TCC is an easily accessible location for many people, and he expects a crowd of about 100 people to come view the eclipse.

Flandrau Planetarium and the Tucson Amateur Astronomy Association will provide several telescopes and binoculars for people who come out to see the eclipse and other visible things in the night sky, Magee said.

Michael Terenzoni, astronomy coordinator at the Flandrau Planetarium, said he has seen many eclipses in the past and feels this will be the best opportunity in the next 11 years for people to see one.

"The issue with lunar eclipses is people don't want to wake up (to see it)," Terenzoni said. "If people are interested, they have to see this one."

Terenzoni, who helped organize the viewing with Magee, said lunar eclipses are best viewed from a dark area with a good pair of binoculars.

"If you want to get the full effect, you want to go out into the desert," Terenzoni said.

Thomas Fleming, associate astronomer at the Steward Observatory, said though it is not uncommon for lunar eclipses to occur, he feels it is exciting when it happens.

"It is a fun thing," Fleming said. "It is like going to a firework show on the Fourth of July."

Fleming said he approximates the average person will see ten good lunar eclipses in their lifetime.

"This is just a nice thing to get people excited about astronomy," Fleming said.

The free public viewing will be at parking lot D of the TCC, where the lights will be turned off to make the area as dark as possible.

The lot is located on the corner of Granada Avenue and Cushing Street.

The eclipse-viewing event is co-sponsored with the Rio Nuevo Redevelopment Project and the TCC.