Skylights featured on Astronomy Picture of the Day

Scout Report Selection Webivore Selection SpaceCareers Selection

Skylights featured nine times on Earth Science Picture of the Day: 1 2 3 4 5 6 7 8 9

Green and blue

Photo of the Week. Who says green and blue don't go together?

Astronomy news for the week starting Friday, February 12, 2010.

We start the week in the "dark of the Moon," as our companion goes through its new phase the evening of Saturday, February 13, the waning crescent too far gone to be visible that morning. The following day, is of course Valentine's Day. It's a non-astronomical holiday, but happy Valentine's to everybody anyway. Look then the next night, that of Monday the 15th, to see waxing crescent in southwestern evening twilight. Filled with diminising Earthlight, the Moon subsequently grows toward first quarter, that phase not reached until early next week (Sunday the 21st). The Moon passes apogee (where it is farthest from the Earth) almost exactly a day before the new phase, which will weaken the highest tides at the coasts (tides dependent on the inverse cube of the lunar distance).

Jupiter is now difficult to see in bright southwestern evening twilight and is for all purposes gone from view. But take heart, as it is gradually being replaced by Venus. The two make a close, though nearly invisible, companionship at mid-month. Watch during February's remainder to get your first glimpse of the second planet from the Sun.

That pretty much leaves the planetary sky to Mars and Saturn. Already well up at sunset, the red planet crosses the meridian to the south around 11 PM among the stars of western Cancer between the Beehive Cluster and the Pollux-Castor pair of Gemini. Well before Mars transits the meridian, at about 8:30 PM, Saturn rises in Virgo some four degrees to the east of the Autumnal Equinox rather marking the spot where we find the Sun on the first day of autumn. In invisible planetary news, Neptune celebrates Valentine's Day by passing conjunction with the Sun.

Looking deeper into the sky, the asteroid Vesta makes a fine appearance as it passes opposition with the Sun on Wednesday the 17th. Though the fourth asteroid discovered, and with a diameter of 510 kilometers (317 miles) the third largest, Vesta is nevertheless the brightest of the bunch, and near opposition is actually visible to the naked eye, though binoculars are a far better choice. The asteroid, part of a debris belt between Mars and Jupiter, spends much of February and March moving retrograde through the Sickle of Leo. The night of opposition, sixth magnitude Vesta is easily found just to the south of second magnitude Algieba, Gamma Leonis, the Sickle's second brightest star, indeed right between Algieba and the fifth magnitude star 40 Leonis, which lies just under half a degree below its brighter second-magnitude neighbor. This is one of the best chances you will ever have to see an asteroid "live."

While spring may be near, the winter constellations still hold forth in the early-to-mid evenings. Look for the pentagon of Auriga nearly overhead in mid- temperate latitudes. Its southernmost star, Gamma Aurigae, actually in Taurus, also serves as the Bull's northern horn, and is more formally known as Elnath, or Beta Tauri. To the south of course is one of the greatest figures of the sky, Orion, the Hunter.
Valid HTML 4.0!