On the night of Jan. 29, the astronomers at the Pan-STARRS PS1 telescope atop Haleakala decided to "run it flat out" in killer-asteroid hunting mode, and despite uncooperative weather, they bagged a record 19 "near-Earth objects" in one night.
"We wanted to show what we could do," said Nick Kaiser of the University of Hawaii Institute for Astronomy on Thursday. Part of the goal was to encourage more funding from the Air Force Research Laboratory and the National Science Foundation, but "it was fun," Kaiser said.
The Maui scope found 30 candidate objects, but each had to be confirmed individually, and that usually requires the cooperation of other observatories. The others were willing, but snowstorms in the eastern states interfered, and in the end, the orbits of only 19 of the 30 were pinned down.
It means observing the asteroid - a rock whizzing through space - at different times, but after two or three days, the search area becomes too large to cover.
Of the 19 confirmed, the sizes ranged from about 50 meters in diameter to "as big as 500 meters," Kaiser said.
Pan-STARRS is shorthand for Panoramic Survey Telescope & Rapid Response System. PS1 is the prototype for a battery of four telescopes that are intended for Mauna Kea.
PS1 was installed at Science City atop Haleakala in May and has the world's largest digital camera (designed at UH) - 1,400,000,000 pixels. The diameter of the scope is 1.8 meters, or 70 inches.
Having proved the concept, Kaiser said astronomers are now thinking of even bigger, better hardware.
"This record number of discoveries shows that PS1 is the world's most powerful telescope for this kind of study," said Kaiser, who heads the Pan-STARRS project. "NASA and the U.S. Air Force Research Laboratory's support of this project illustrates how seriously they are taking the threat from near-Earth asteroids."
Asteroids down to 40 meters are a threat. Smaller than that and they will burn up in the atmosphere.
NASA has set a goal of discovering near-Earth asteroids down to 140 meters. Kaiser said the full Pan-STARRS array planned for Mauna Kea could discover 90 percent of the 400- to 500-meter objects in 10 years.
Since asteroids are in orbits that take three to five years to circle the sun, that would give the observers two or three chances a decade to find them - if the weather cooperates.
On the night of Jan. 29, Pan-STARRS software engineer Larry Denneau was in his UH-Manoa office processing the PS1 data as it was transmitted from the Maui over the Internet.
Kaiser said the other astronomers were excitedly kibitzing, but Denneau shooed them away. He was busy.
The suspects were sent to the Minor Planet Center in Cambridge, Mass., which collects and disseminates data about asteroids and comets, so that other astronomers could re-observe the objects.
"Usually there are several Mainland observatories that would help us confirm our discoveries, but widespread snowstorms there closed down many of them, so we had to scramble to confirm many of the discoveries ourselves," said institute astronomer Richard Wainscoat.
The Canada-France-Hawaii telescope at Mauna Kea was helpful. The next night, two rocks were confirmed as near-Earth - plotted to come within 1.3 times the radius of Earth's orbit.
That is millions of miles, but any that come that close are susceptible to having gravity of planets shift their orbits to bring them closer on another trip. Then snow closed the Mauna Kea observatory.
The next night, nine more were confirmed before fog interfered. The third night, four were sought but only one was found. The rest had moved too far away to be spotted even in the very wide field of the C-F-H telescope.
The other confirmations were made in Arizona, Illinois, Italy, Japan, Kansas, New Mexico, and the United Kingdom, and by the Faulkes Telescope on Haleakala.
On the Web:
* Pan-STARRS: pan-starrs.ifa. hawaii.edu/public
* PS1: ps1sc.org
* The Minor Planet Center:
minorplanetcenter.net
* Harry Eagar can be reached at heagar@mauinews.com.
