After being out of view for three months, Jupiter is once again high enough in the morning sky to be observable, and reports are arriving from around the world on the state of the impact sites created last summer. As of December 18th, says David Levy, the dark material was still there and still obvious. One part of the new belt thickens to a large spot. Two days later Sam Whitby saw the newly formed belt too. He agrees with Levy that it's the second-most obvious belt on Jupiter, after the South Equatorial Belt. "You can't miss it," he says. And astronomers using the 3.5-meter reflector on Calar Alto report that a continuous bright band can be seen at the infrared wavelength of 1.7 microns. This means that considerable material remains high in the atmosphere. According to astronomer Tom Herbst, "The band has not faded significantly since September, indicating that this ejecta may take years to settle out of the upper atmosphere."
Jupiter currently rises more than two hours before the Sun, sitting above the horizon in the southeast to the lower-left of brilliant Venus. It will continue to move away from the Sun at nearly 1 degree per day. By mid-January its elongation will exceed 45 degrees, making Jupiter once again observable by the Hubble Space Telescope. According to MIT astronomer Heidi Hammel, who led the HST comet-crash effort earlier this year, observing time has been requested but not yet approved.
Speaking of HST, this week the Space Telescope Science Institute released a new composite image of Saturn taken by the telescope on December 1st by Reta Beebe and Amy Simon. The image shows a huge bright storm raging north of the planet's equator. This storm is less turbulent than the big one in 1990, but it was reasonably obvious when picked up earlier this year by amateur observers.
New Moon falls on New Year's Day, an interesting coincidence with interesting consequences. First, Robert C. Victor points out that during December the Moon has been observable for 28 nights in succession. Also, Victor says observers in southwestern states and Hawaii have the opportunity to spot the very thin crescent of a very old Moon on Saturday morning, December 31st. On the East Coast the crescent will be 23 hours from new, 20 hours in the west, and 18 from Hawaii. Look to the southeast about 45 minutes before sunrise.
Asteroid sleuth George Viscome wants you to know about an interesting pairing coming up this week. On the 29th, asteroid 5751 will nearly cross the Horsehead Nebula just south of Zeta Orionis in Orion's Belt. The asteroid is faint, however, only magnitude 13.3.