Moon Will Play Peekaboo Tonight

Sky gazers in Southern California and much of the rest of the planet will witness a total lunar eclipse tonight, weather permitting, as the moon orbits opposite the sun and makes a rare pass through Earth’s shadow.

Beginning at 6:21 p.m. PDT, the rising full moon will travel into the outer region of this shadow, called the penumbra, and to viewers in the eastern United States and much of the world it will appear that the normally white lunar surface gradually changes to orange or red.

This color change is the result of sunlight being bent around the Earth, filtered through its dust- and pollution-laden atmosphere and refracted down to the moon’s surface, according to Griffith Observatory astronomer John Mosley. The airborne particles in our atmosphere will filter out all colors but an orangy red, Mosey said.

Unfortunately for viewers in California, this process will occur before the moon rises on the West Coast. By the time the moon does appear in the Western sky, a little after 7:30 p.m., it will already be completely enveloped in the innermost part of the planetary shadow known as the umbra. At that point, called totality, the moon will still appear red, but because of its location deep in the shadow it will not be as bright as when seen earlier in other parts of the world.

The moon’s totality will last for about 95 minutes, and at 8:56 p.m. it will begin its journey out of the umbra and back into the penumbra.

By 9:56 p.m. the moon will have completely left the umbra, and an hour later it will be completely out of Earth’s shadow.

Southern Californians who want to see the eclipsed moon should look in the southeast sky after sunset, a few inches above the horizon, Mosley said. The best time for viewing will be between 8:30 p.m. and 8:45 p.m., and a pair of binoculars or a telescope will make viewing easier, he said. In addition, Griffith Observatory will be open to the public during the eclipse and will have more than a dozen telescopes set up for public viewing between 7:30 p.m. and 10 p.m.

TOTAL LUNAR ECLIPSE

Aug. 16, 1989

A lunar eclipse occurs when the moon passes through the shadow of the Earth. (A solar eclipse, on the other hand, happens when the Earth passes through the shadow of the moon.)

From the moon the Earth would appear to have a bright ring around it at totality, caused by sunlight bent in the Earth’s atmosphere. 1. Before eclipse: Full moon 2. Partial eclipse begins: 6:21 p.m. PDT 3. Total eclipse begins: 7:20 p.m. PDT 4. Middle of eclipse : 8:08 p.m. PDT 5. Total eclipse ends: 8:56 p.m. PDT 6. Partial eclipse ends: 9:56 p.m. PDT 7. Eclipse over: 10:53 p.m. PDT

Source: Sky & Telescope magazine