Northern Autumn marks the beginning of Aurora Season

The coming of Northern Autumn marks the beginning of aurora season. Sky watchers around the arctic circle should be alert for Northern Lights in Sept. and Oct.

Click Photos To Enlarge.

Lake Myvatn, Iceland Sept. 17, 2009

North Pole, Alaska Sept. 15, 2009

Yellowknife, Northwest Territories, Sept. 11, 2009

Kola peninsula, Russia, Mt. Khibiny Sept. 14, 2009

Little Crater Targeted for Big Splash

Planetary scientists won't get a re-do when NASA's LCROSS spacecraft and its Centaur carrier rocket slam into the Moon on October 9th. They've got one chance only to strike a permanently shadowed and presumably water-rich crater floor near the lunar south pole. So for weeks they've anguished over where ground zero will be. As noted by project scientist Anthony Colaprete notes, the selection process spawned a "vigorous debate" among researchers.

With just under a month to go, they've announced their choice: an unnamed 11-mile-wide (17-km) craterlet astride the rim of Cabeus A. It's got desirable target characteristics — a flat boulder-free floor, for instance, and a location favorable for telescopes back on Earth to watch the resulting plume of debris that should balloon above the crash site.

Mostly, they've picked what they've dubbed Cabeus A1 because it's what one official calls a "sweet spot," a spot where detectors aboard the Lunar Reconnaissance Orbiter (which accompanied LCROSS to the Moon) hint that the always-dark dust might contain roughly 1½% water ice.

Neither Cabeus A1 nor nearby Cabeus A were on the list of candidate target craters announced back in July, and frankly the project's pick is surprisingly far from the lunar south pole (latitude –81½°). This is good news for both professional and amateur astronomers hoping to catch a glimpse of the impacts.

Officials aren't saying how much they've determined about the crater, but LRO carries two instruments that potentially could have moved the bull's eye squarely onto Cabeus A1.

One is the Lyman-Alpha Mapping Project (LAMP)can literally see in the dark, using reflected ultraviolet radiation from starlight to image the permanently shadowed lunar terrain.

Meanwhile, the Lunar Exploration Neutron Detector (LEND) can detect the presence of hydrogen, which almost has to be in water ice, down to 100 parts per million. LEND was built by the Moscow's Space Research Institute, and as best I know this is the first and only time a Russian-built instrument has flown on one of NASA's spacecraft (not counting the International Space Station).

At today's press briefing, Daniel Andrews (LCROSS project manager at NASA-Ames Research Center) assured everyone that the spacecraft was ready for its big finale. The team had a scare last month when an errant sensor caused wild thruster firings that squandered about half of the spacecraft's maneuvering fuel. Andrews also announced that the LCROSS mission has been dedicated to the memory of the late Walter Cronkite, the longtime television news reporter and anchor who followed NASA's missions from the Mercury program in the early 1960s to Space Shuttle.

So now it's time to start getting ready to observe lunar fireworks on October 9th. The timing, 4:30 a.m. Pacific Daylight Time, favors the big guns atop Mauna Kea in Hawaii in throughout western North America.

Sadly, I'll be in Puerto Rico that week — attending, ironically, a meeting of planetary scientists. Will someone please let us all know how things turn out?

Refurbished Hubble Shows Its Stuff

After the huge success of the Hubble Space Telescope repair mission last May, and the nailbiting suspense as astronauts wrestled to swap out much of the telescope's gear, the world was eager for new pictures and science. But it has taken several months to test and calibrate the new instruments and bring everything up to speed.

The first big public release was an unscheduled image of a surprise event: the appearance in mid-July of a black impact mark in Jupiter's south polar region. Now Hubble's handlers are throwing their previously scheduled coming-out party.

From a NASA press release:

"Topping the list of new views are colorful, multi-wavelength pictures of far-flung galaxies, a densely packed star cluster, an eerie "pillar of creation," and a "butterfly" nebula. Hubble's suite of new instruments allows it to study the universe across a wide swath of the light spectrum, from ultraviolet all the way to near-infrared. In addition, scientists released spectroscopic observations that slice across billions of light-years to probe the cosmic-web structure of the universe and map the distribution of elements that are fundamental to life as we know it.

"This marks a new beginning for Hubble," said Ed Weiler, associate administrator for NASA's Science Mission Directorate at NASA Headquarters in Washington. "The telescope was given an extreme makeover and now is significantly more powerful than ever, well-equipped to last into the next decade."

Leading the morning press conference was Sen. Barbara Mikulski (D-MD), who can take credit for pushing the repair mission to happen despite NASA's initial reluctance. “I fought for the Hubble repair mission because Hubble is the people’s telescope,” said Mikulski, chair of the subcommittee that funds NASA. “I also fought for Hubble because it constantly rewrites the science textbooks. It has more discoveries than any other science mission. Hubble is our greatest example of our astronauts working together with scientists to show American leadership and ingenuity."

Jupiter dominates the Evening Sky & Dazzling Venus the Morning Sky

Jupiter continues to dominate the evening sky. Based on the comments left on this blog, many people have been noticing Jupiter in the southeast sky during the evening. At magnitude -2.8, Jupiter is ~13 times brighter than the brightest stars in the sky this month. Of all the planets, only Venus, and on very rare occasions Mars, are brighter.



Venus is the brightest “star” in the sky a hour or so before dawn. It was at its highest in the morning sky last month but now begins its slow crawl lower though it will remain an easy object for early risers  over the next 2-3 months. For binocular and telescope users, Venus will appear nearly full and is much smaller than it appeared this spring (now 12″ across versus 50″ last spring).