Febuary 2001 Sky from Keeble Observatory

I promised a return to "neat astronomy web links" for this month, but I'm only going to give you one, plus some upcoming news.

For almost a year, the NEAR Shoemaker spacecraft (NEAR = Near Earth Asteroid Rendezvous) has been orbiting a 21 mile long potato-shaped rock named 433 Eros. It went into orbit, appropriately on Valentine's Day, as the first ever spacecraft to orbit an asteroid. Since then, controllers have maneuvered it into low and high orbits, mapping and photographing the heavily cratered surface at resolutions as fine as a few meters. Eros is currently about 1.5 astronomical units (1 AU = average Earth-Sun distance) from the Sun, roughly in the same direction as the planet Venus. It is about 2.5 AU from Earth.

You can follow the mission results at http://www.jhuapl.edu/ - but you'd better look quickly! The orbit was lowered from its 22 mile circular orbit into an elliptical path that carried it within 3 or 4 miles of the surface, beginning on January 24th. On the 28th of January, it was lowered to within a mile, then returned to its circular, 22 mile radius. On February 12, flight controllers will fire the spacecraft thrusters to initiate a "controlled descent" to the surface, attempting the first ever soft landing on an asteroid! During the last three miles of the descent, the highest resolution cameras will begin returning the most detailed closeups ever, possibly able to resolve objects as small as a few inches.

The craft was not designed for a landing, and the survival of the probe is not a mission objective, so this maneuver ought to be the last hurrah for NEAR Shoemaker. "Controlled descent" is a euphemism for "intentional crash landing!"

Speaking of crash landings, another controlled descent is currently scheduled for March 6th. Russian flight controllers plan to fire rockets on their aging, failing space station to drop MIR into the Pacific Ocean, hopefully avoiding damage or injury to earth-bound humans or their property. The "disposal" operations could be put on hold if they have difficulty maintaining remote control of the orbital laboratory.

Launch of a robot supply ship, carrying the fuel for the de-orbit burn, was delayed because of a power failure on MIR. That refueling operation was apparently successful, so flight controllers are proceeding with the planned de-orbit operations. If they cannot maintian control remotely, they may have to send a crew to fix the problem in order to retire successfully the 15 year old laboratory.

Lunar phases for February: First Quarter, appropriately on the 1st at 9:02 am; Full Moon on the 8th, at 2:12 am; Last Quarter at 10:23 pm on the 14th; New Moon at 3:21 am on the 23rd.

Evening planet watchers can still get a good view of Venus for several hours after sunset. It is that brilliant "star" high over the southwest horizon. Binoculars or a small telescope should allow you to see its crescent grow larger but thinner as Venus catches up to Earth in its orbit. Jupiter and Saturn are not as bright, and somewhat higher in the sky, but still brighter than most of the evening stars. Mars is visible in the predawn twilight to the south. Don't confuse it with Antares, the bright red star in Scorpio (whose name means "against Mars") south and east of Mars. Mars will be the brighter of the two. Our overhead view at mid-month, about 3 hours after sunset, finds Castor and Pollux in the constellation Gemini (the Twins) just east of zenith, with Capella and Elnath in the constellation Auriga just to the west of zenith. To the southwest is the unmistakable shape of Orion, the Hunter following Taurus. Look for Jupiter and Saturn close to Aldebaran, the bright heart of the Bull. Behind and a bit below Orion is Sirius, also known as the Dog Star in the constellation Canis Major. Sirius is the brightest star visible in the night sky from Earth, and is known to have a companion white dwarf star orbiting close by. This is further evidence, along with other binaries (like Castor and Pollux, and Mizar/Alcor in Ursa Major to the north) that most stars form with close companions. Some are stars, others are planets, like our own! To the east, Leo is rising, with the bright star Regulus marking the heart of the Lion. You may recall from last month's essay, that Regulus is implicated in a series of planetary alignments which may, collectively, underlie our traditional story of the Star of Bethlehem.