This story was updated on Jan. 2.
As the year 2011 comes to a close, some might wonder what is looming sky-wise for 2012? What celestial events might we look forward to seeing?
I've selected what I consider to be the top 12 "skylights" for this coming year, and list them here in chronological order. Not all these events will be visible from any one locality … for the eclipses, for instance, you'll probably have to do some traveling … but many can be observed from the comfort of your backyard.
Hopefully your local weather will cooperate on most, if not all, of these dates. Clear skies!
Jan. 4: Quadrantid meteor shower peaks
This meteor shower reaches its peak in the predawn hours of Jan. 4 for eastern North America. The Quadrantid meteor shower is a very short-lived meteor display, whose peak rates only last several hours. The phase of the moon is a bright waxing gibbous, normally prohibitive for viewing any meteor shower, but the moon will set by 3 a.m., leaving the sky dark for a few hours until the first light of dawn; that's when you'll have the best shot at seeing many of these bluish-hued meteors.
From the eastern half of North America, a single observer might count on seeing as many as 50-to-100 "Quads" in a single hour. From the western half of the continent the display will be on the wane by the time the moon sets, with hourly rates probably diminishing to around 25 to 50 meteors.
Feb. 20 to March 12: Best evening apparition of Mercury
In February and March, the "elusive" innermost planet Mercury moves far enough from the glare of the sun to be readily visible soon after sunset. Its appearance will be augmented by two other bright planets (Venus and Jupiter), which also will be visible in the western sky during this same time frame.
Mercury will arrive at its greatest elongation from the sun March 5. It will be quite bright (-1.3-to-0 magnitude) before this date and will fade rapidly to +1.6 magnitude thereafter. Astronomers measure the brightness of objects in terms of magnitude, with lower numbers corresponding to brighter objects.
March 3: Mars arrives at opposition
On March 3, the Earth will be passing Mars as the two planets wheel around the sun in their respective orbits. Because Mars reaches aphelion — its farthest point from the sun — on Feb. 15, this particular opposition will be an unfavorable one. In fact, two days after opposition, Mars will be closest to Earth at a distance of 62.6 million miles.
Compare this with the August 2003 opposition when Mars was only 34.6 million miles away. Nonetheless, even at this unfavorable opposition the fiery-hued Mars will be an imposing naked-eye sight, shining at magnitude -1.2, just a bit dimmer than Sirius, the brightest star, and will be visible in the sky all night long.
March 13: Brilliant "double planet"
The two brightest planets, Venus and Jupiter, team up to make for an eye-catching sight in the western sky soon after sunset. They will be separated by 3 degrees on this evening, Venus passing to the northwest (upper right) of Jupiter and shining nearly eight times brighter than "Big Jupe." Although they will gradually go their separate ways after this date, on March 25 and 26, a crescent moon will pass by, adding additional beauty to this celestial scene.
May 5: Biggest full moon of 2012
The moon turns full at 11:35 p.m. Eastern Daylight Time and just 25 minutes later it will arrive at its closest point to the Earth in 2012, at a distance of 221,801 miles. Expect a large range in ocean tides (exceptionally low to exceptionally high) for the next few days. [Photos: 'Supermoon' of 2011]
May 20: Annular eclipse of the sun
The path of annularity for this eclipse starts over eastern China and sweeps northeast across southern and central Japan. The path continues northeast then east, passing just south of Alaska's Aleutian Island chain. The path then turns to the southeast, making landfall in the western United States along the California-Oregon coast. It will pass over central Nevada, southern Utah, northern Arizona, the extreme southwest corner of Colorado and most of New Mexico before coming to an end over northern Texas.
Since the disk of the moon will appear smaller than the disk of the sun, it will create a "penny on nickel" effect, with a fiery ring of sunlight shining around the moon's dark silhouette. Locations that will witness this eerie sight include Eureka and Reading, Calif.; Carson City, Reno and Ely, Nev.; Bryce Canyon in Utah; Arizona's Grand Canyon; Albuquerque and Santa Fe in New Mexico and just prior to sunset for Lubbock, Tex.
A partial eclipse of the sun will be visible over a large swath of the United States and Canada, including Alaska and Hawaii, but no eclipse will be visible near and along the Atlantic Seaboard.
June 4: Partial eclipse of the moon
This partial lunar eclipse favors the Pacific Ocean; Hawaii sees it high in the sky during the middle of its night. Across North America the eclipse takes place between midnight and dawn. The farther east one goes, the closer the time of moonset coincides with the moment that the moon enters the Earth's dark umbral shadow.
In fact, over the Northeastern United States and eastern Canada, the only evidence of this eclipse will be a slight shading on the moon's left edge (the faint penumbral shadow) before moonset. Over the Canadian Maritimes, the moon will set before the eclipse begins. At maximum, more than one-third of the moon's lower portion (37.6-percent) will be immersed in the umbra.
June 5: Rare transit of Venus across the sun
The passage of Venus in front of the sun is among the rarest of astronomical events, rarer even than the return of Halley's Comet every 76 years. Only six transits of Venus are known to have been observed by humans before: in 1639, 1761, 1769, 1874, 1882 and, most recently, in 2004.
The next one will occur in the year 2117. When Venus is in transit across the solar disk, the planet appears as a distinct, albeit tiny, round black spot with a diameter just 1/32nd of the sun. This size is large enough to readily perceive with the naked eye. HOWEVER ... prospective observers are warned to take special precautions (as with a solar eclipse) when attempting to view the silhouette of Venus against the blindingly brilliant solar disc.
The beginning of the transit will be visible from all of North America, Greenland, extreme northern and western portions of South America, Hawaii, northern and eastern portions of Asia including Japan, New Guinea, northern and eastern portions of Australia, and New Zealand. The end will be visible over Alaska, all of Asia and Indonesia, Australia, Eastern Europe, the eastern third of Africa, and the island nation of Madagascar.
Aug. 12: Perseid meteor shower
Considered to be among the best of the annual displays thanks to its high rates of up to 90 per hour for a single observer, as well as its reliability. Beloved by summer campers and often discovered by city dwellers who might be spending time in the country under dark starry skies. [10 Perseid Meteor Shower Facts]
Last summer a bright moon wrecked the shower by blotting out many of the fainter streaks, but in 2012 the moon will be three days past last quarter phase on this peak morning – a fat waning crescent presenting only a minor nuisance for prospective observers.
Nov. 13: Total eclipse of the sun
The first total solar eclipse since July 2010. Virtually the entire path of totality falls over water. At the very beginning, the track cuts through Australia's Northern Territory just to the east of Darwin, then across the Gulf of Carpentaria, then through northern Queensland, passing over Cairns and Port Douglas before heading out to sea.
The rest of the eclipse path, including the point of the maximum duration of totality (4 minutes, 2 seconds) is, unfortunately, pretty much wasted by falling over the open waters of the Pacific Ocean.
Dec. 13-14: Geminid meteor shower
If there is one meteor display guaranteed to put on a very entertaining show it is the Geminid meteor shower. Now considered by most meteor experts to be at the top of the list, surpassing in brilliance and reliability even the August Perseids.
Bundle warmly against the winter chill; you can start observing as soon as darkness falls on the evening of Dec. 13 as Gemini starts coming up above the eastern horizon and continue through the rest of the night. Around 2 a.m. when Gemini is almost directly overhead, you might see as many as two meteor sightings per minute … 120 per hour! And the moon is new, meaning that it will not be a factor at all.
Dec. 25: Christmas evening and Jupiter
On Christmas, many will be looking skyward and wondering what that brilliant silvery "star" is hovering just above the waxing gibbous moon. It's not a star (or Santa returning to the North Pole), but the largest planet in our solar system, Jupiter, serving as a sort of holiday ornament with our nearest neighbor in space to cap off a year of interesting and predictable sky events that we all can enjoy!
This story was updated to include the correct date of the next Venus transit of the sun, which occurs in 2117.
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.