Venus in Transit 2012: Not An Eclipse, But Similar

A little after 3 p.m. Tuesday, the West Coast will have an opportunity to witness one of the rarest predictable celestial events: a transit of Venus across the sun.

Often referred to as the "Evening Star" or "Morning Star," Venus is the brightest natural object in our sky after the Sun and the Moon. As the second planet from the Sun, it's closer to the Sun than the Earth is. 

A "transit" of Venus occurs when Venus passes between us and the Sun in such a way that we can see Venus's silhouette backlit by the Sun's brilliant light. It last happened in 2004, but it won't happen again until 2117. Unless you plan to shatter some human longevity records, this is probably your last chance.

Were Venus either large enough or close enough to block out the Sun's light as it passed, we would call this event an eclipse, as we do when the Moon passes between the Earth and the Sun. Venus, however, is a little bit smaller than the Earth and about 27 million miles away. When its tiny silhouette is viewed against the Sun, which lies another 66 million miles beyond, it can offer viewers a dramatic sense of the solar system. 

Assuming sufficiently clear skies, the transit will be visible for us starting at about 3:06 p.m. PST on Tuesday and will remain so until the sun sets. Those in the central and western U.S. will be able to enjoy it longer, while viewers in Alaska, Japan, and large sections of Australia, China, and Russia will be able to see it in its entirety. By the time the Sun rises on the East Coast on Wednesday, Venus will have completed the transit.

How to watch

Never look directly at the sun with your naked eyes. You can damage your eyes. Likewise, viewing the sun with either binoculars or a telescope can direct the sun's magnified rays directly into your eyeball and cause serious injury―think about what happens to ants under a magnifying glass.

Sunglasses do not provide sufficient protection. If you know someone who works in plumbing or construction, ask them if they have any #14 welder's glass. You can look directly at the sun through this material without risking injury.

If you have a tripod or a partner and a pair of steady hands, you can use binoculars to project an image of the Sun onto a white piece of paper. Remember, don't look through your binoculars at the sun!

If none of these options is feasible, Griffith Observatory will host a public event at 3:06 p.m. to 8:02 p.m. at 2800 East Observatory Rd., Los Angeles. The building opens at noon and closes at 10 p.m. Telescopes are available for free viewing of the transit and will have the proper filters.

The Griffith Observatory's Stellar Emporium gift shop will stock official Griffith Observatory Solarama viewing filters and Griffith Observatory eclipse glasses for purchase.

Where to Watch

Since closes at 8 p.m. on weekends during daylight saving time you could try to head there and watch the show as long as you have a safe way to view it. The sun should be sufficently high in the sky that the phenomenon should be visible from lower ground as well.

One destination to catch a stunning vista is the , which ascends 1500 feet toward the ridgeline of the mountain and is not far from civilization.

To get to the site from the 210 Freeway heading west, take the La Crescenta Avenue exit. Turn right to continue onto Oakmont View Drive followed by a left on Barnes Circle Drive.

Continue for a third of a mile and then make a right onto Beaudry Terrace. Drive down Beaudry Terrace until it becomes Beaudry Boulevard, the destination is on the right. Look for large fence and a concrete wash marking the path.

The actual trail head is beyond the main gate next to the wash. Remember to always bring a head lamp, tell someone where you’re going and watch your step.

offers these local viewing options:

Remember to check park hours before entering.

offers these spots:

• Cobb Estate
• Eaton Canyon

Though it's not quite the same as viewing the phenomenon in person, there are several places to watch the transit of Venus online:

• The Slooh Space Camera will offer an 8-hour webcast of the transit that includes real-time video feeds from 10 telescopes around the world.
• Astronomers Without Borders will carry a video stream of the transit from the Mount Wilson Observatory in California.
• NASA will offer a live video feed from Mauna Kea Observatory in Hawaii with expert commentary.
• The San Francisco Exploratorium will host an online video stream from the Mauna Loa telescope in Hawaii.

Lastly, there's Don Pettit, an astronaut currently aboard the International Space Station. Pettit's not doing a video feed, but he will become the first person to ever photograph a transit of Venus from outer space.