Skywatcher's Almanac: Celestial Highlights in 2007

by Joe Rao, SPACE.com Skywatching Columnist

Date: 05 January 2007 Time: 06:16 AM ET

From a potentially spectacular summer meteor shower to a pair of lunar eclipses and compelling appearances of the planets, this year will be an excellent one for skywatching.

And right now, a newfound comet is brightening rapidly and could put on a fantastic show over the next few days.

Meanwhile, this astronomical almanac of sorts can serve as a planning guide for the rest of the year. Specific events will be discussed in greater detail on SPACE.com just prior to their occurrences.

THE PLANETS

Mercury will have two very good evening apparitions for Northern Hemisphere observers in 2007. The better of the two comes during late January into the first half of February when Mercury will be evident as a bright yellowish-orange "star" low in the west-southwest sky, to the lower right of brilliant Venus. Mercury will arrive at its greatest elongation, 18-degrees to the east of the Sun on Feb. 9. The other good evening apparition comes during the last half of May into the first week of June, when it will shine low in the west-northwest from one and a half to 2 hours after sundown.

For early risers, Mercury will put on an excellent showing through much of November, being readily visible in the east-southeast sky for up to 90 minutes before sunrise. In fact, from Nov. 5 through the 12th, Mercury will rise in a completely dark sky before the start of morning twilight.

A moderately good morning apparition of Mercury stretches from mid July into the opening days of August, with this rocky little world glowing through the midsummer dawn twilight near to the east-northeast horizon up to 90 minutes before sunrise.

Venus will have a spectacular 2007, as explained in our previous Venus Viewer's Guide. It will be a brilliant evening object from now through the start of August, dominating the western evening sky. It will then transition into the morning sky, becoming a very prominent object in the eastern sky from the final days of August on through the balance of the year.

Mars is currently a morning object, teamed with Jupiter and the bright red star Antares, but from now through the end of April it will be rising only minutes before the start of morning twilight. It's rather unimpressive during this interval, but beginning in May it starts a very slow climb up into the eastern sky and gradually brightens as it approaches the Earth. Toward the end of August it's rising around midnight (local daylight time). By the start of October it will shine as bright as a zero-magnitude star and by the second week of December, it will have swelled in brilliance to rival even Sirius, the brightest of all the stars. Mars is nearest to Earth on December 18th at a distance of 54.8 million miles (88.2 million kilometers) and is at opposition on Christmas Eve when it rises near sunset, peaks high in the south about midnight and sets near sunrise.

Jupiter starts 2007 in the morning sky, rising in the east-southeast around 4:30 a.m. It rises about four minutes earlier each day, however, so it ever-so-gradually will begin to appear at more convenient hours: rising around midnight (local daylight time) by mid April and around the end of evening twilight by mid May. It will arrive at opposition on June 5, and then will be a prominent evening object for the rest of the year. Unfortunately, it will spend much of the year in the Scorpius-Ophiuchus region of the sky, not far from the ruddy star Antares, which means it will not get very high up for those living north of latitude 45-degrees north.

Saturn will be in prime position for evening viewing during the winter and early spring months, sedately shining like a very bright, but not dazzling, yellowish-white zero-magnitude "star" in Leo, the Lion. By mid-April it is already past the meridian as darkness falls, and during July it gradually becomes swallowed up by the evening twilight glow. It reappears in the eastern morning sky by mid-September. Brilliant Venus pays Saturn a visit twice in 2007, the first in the July evening sky and the second in the October morning sky. The famous ring system is visible in small telescopes magnifying 30-power or more, but their inclination toward Earth diminishes quite noticeably, especially later in the year.

METEOR SHOWERS

The peak of the annual performance of the famous Perseid Meteor Shower very nearly coincides with a New Moon late on the night of Aug. 12-13, which will make for excellent observing conditions for viewing meteors at rates of 50 to 100 per hour.

Astronomer Peter Jenniskens at NASA/Ames Research Center is predicting an outburst of bright meteors on the morning of Sept. 1, for those living in western North America [Full Story]. Unfortunately, a bright gibbous Moon will be in the sky, but hourly rates might possibly be in the tens to hundreds.

The December Geminids-which many now consider to be the best display of the year-occurs in 2007 when the Moon is a waxing crescent and sets early in the evening, meaning excellent viewing conditions for the nights of Dec. 13 and 14, when 60 to 120 meteors per hour may be seen.

ECLIPSES

There will be two total lunar eclipses in 2007. The first is on March 3rd. Europe and Africa are in prime position to see it, though parts of eastern and central North America will get a view of it as the Moon rises that evening. The other total eclipse comes on Aug. 28, and will favor the Pacific Rim. Western and central North America will be able to see it much of it just prior to moonset; eastern North America's view will be interrupted by the setting Moon.

A partial eclipse of the Sun occurs on March 19th for eastern Asia; from parts of Alaska, the opening stages of this eclipse might be glimpsed just before sunset on the evening of the 18th. On Sept. 11 another partial solar eclipse will take place, this time over southern South America and Antarctica.

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.