Ingress and Egress of the Lunar Occultation of Venus on Monday August 13, 2012. Credit Rick Baldridge, Chairman of Peninsula Astronomical Society (PAS) Oakridge Observatory.

Today’s occultation of Venus by the moon will be visible from much of North America. The farther west you are, the better the view.

Along the U.S. Pacific Coast, the moon will stand about halfway up in the southwest sky when it passes in front of Venus between roughly 1:05 and 1:45 p.m. Pacific Daylight Time. When Venus emerges between 2:20 and 2:50 p.m. PDT, the moon will be about one-third up from the west-southwest horizon.

For a map showing the region of visibility of this “Venus eclipse” as well as Universal Times of its disappearance and reappearance for over 700 cities, click here.

Finding the moon in the daytime may be easy or difficult depending on the clarity of the air. If the sky is clear and blue with little or no haze you should have little problem, but a hazy sky will make the search problematic.

Although Venus appears much smaller (1/75th as large as the moon), it has a much higher surface brightness and may be easier to spot in a bright sky.

If you spot the moon, point a binocular or small telescope at it, focus carefully and you should see Venus nearby.

Telescopes allow the best view

Rick Baldridge at the ready with his telescope. Photo credit: Greg Schmidt.

Perhaps the most satisfying way of enjoying this spectacle will be to watch in a telescope at very low power so that the images of the moon and Venus are both distinct and complete. In contrast to the moon’s delicate crescent shape, Venus will appear half illuminated. The sunlit portions of both objects will, of course, be facing the same direction toward the sun.

Viewed behind the eyepiece of a telescope, Venus will not disappear suddenly. The cratered, 16 percent sunlit lunar crescent will drift eastward toward the brilliant sunlit portion of Venus’ disk. The moon’s rough edge will bite into Venus and rapidly devour it.

Then, just a little over an hour later it will reappear, literally from “out of the blue” from behind the moon’s opposite, unseen limb, taking about 25 seconds to swell back to full brightness.

Those who are blessed with very sharp eyes might possibly watch the entire event with no optical aid at all, although most people will need at least binoculars to watch for the Moon to pass in front of Venus.

Read more from Joe Rao on the occultation of Venus at Space.com!

Posted by: Soderman/NLSI Staff
Source: http://www.lunar-occultations.com/iota/planets/0813venus.htm; Joe Rao: http://www.msnbc.msn.com/id/48639802/ns/technology_and_science-space/#.UClIekRpL-S

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