Jack Pitkin

A skyward glance Wednesday evening could reveal an event that will not be repeated for nearly three years: The full moon will appear to disappear when it drifts through Earth’s shadow.

“Just watch, as the ancient Chinese would say, the dragon take a bite out of the moon,” said Bobby Thompson, an amateur astronomer and former manager of the Clarence T. Jones Observatory. “It is fascinating to see the workings of celestial mechanics.”

A total lunar eclipse occurs when the moon passes directly through the Earth’s shadow, growing gradually dimmer and dimmer until it begins to brighten as it moves outside Earth’s shade.

“It is perfectly safe to watch a lunar eclipse with the naked eye,” said Jack Pitkin, operations manager of the Jones Observatory for the University of Tennessee at Chattanooga. “But if the weather is lousy, forget it.”

Neither a telescope nor a visit to the observatory is necessary to appreciate the majesty of an eclipse, Mr. Pitkin said.

“A pair of binoculars is all you need, that and a clear view of the sky,” he said.

The observatory, which is usually open only on Sunday nights, will be open 9 until 11 Wednesday night for this special event if it is not raining. Observatory staff will conduct imaging and observation studies during the eclipse, Mr. Pitkin said.

While the Jones Observatory staff will be using a 20.5-inch Cassegrain telescope, Mr. Thompson will be using an 8-inch telescope at his Walker County, Ga., home’s backyard observatory.

“I may make some digital videos of the eclipse,” he said. “This is the best time to see the moon moving among the stars. There will be no glow from the moon, just a red object gliding through the night sky.”