For early risers planning to get a jump on ringing in 2011 in North America, an attractive cosmic sight in the predawn sky will precede New Year's Eve: the brilliant planet Venus shining in the vicinity of a lovely crescent moon.
Venus will rise first, early Friday shortly after 3:30 a.m. EST (0830 GMT), followed about 15 minutes later by the slender sliver of the waning crescent moon. The eye-catching duo will quickly gain altitude, and with the arrival of dawn a couple of hours later they will appear roughly one-quarter of the way up from the southeast horizon to the overhead point (known as the zenith).
This sky map shows how Venus and the moon should appear in the southeastern sky to skywatchers with clear weather early Friday.
Not Close, but still striking
This will not be a particularly close conjunction ? Venus will be hovering about 7 or 8 degrees above and to the left of the moon. For comparison, your clenched fist held at arm?s length measures roughly 10 degrees. [Photos of Venus from around the world]
But the two will attract immediate attention because of their great brightness. Astronomers measure the brightness of objects in the sky based on their magnitude ? the lower an object's magnitude number, the brighter it is.
Venus shines at magnitude of minus-4.5, which makes it more than seventeen times brighter than Sirius, the brightest star in the night sky.
The moon will be less than 3 1/2 days from new phase and about 16 percent illuminated. Look for the beautiful phenomenon known as "earthshine" ? sunlight reflected by the Earth, directed toward the moon and dimly illuminating its dark portion with a faint gray-blue glow.
That effect should give an almost three-dimensional appearance to the moon, enhancing the overall scene.
Spot Venus during daylight!
The moon?s proximity relative to Venus will give you an excellent chance to try to glimpse Venus during the daytime. Just take note of where Venus is relative to the moon.
After the sun comes up, locate the moon and then look roughly "one fist" above and to its left. Venus will be visible as a tiny white speck against the blue sky background.
Periodically check the sky during the day and see if you can still see both. If you do, you'll join the elite handful of skywatchers who can claim to have spotted Venus during the daytime hours.
Robert Roy Britt, editor-in-chief of SPACE.com's parent company, Tech Media Network, recently joined the group of Venus daytime spotters along with his family. The view earlier this month, he said, was surprising.
"Venus appeared as a stark pinpoint of white light against the blue morning sky," Britt wrote. "It is extremely hard to find if you don't know exactly where to look, but once you find it, it's startling how bright it is."
- Gallery - Venus Seen From Around the World
- Venus Visible In the Daytime Sky
- Telescopes for Beginners
Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, New York.