Oct 9 2007
The University of Hawaii astronomer who led development of the world's largest and most advanced digital camera for a telescope on Haleakala, Maui, says he is "shocked at how well it's going."
"It's pretty impressive, actually," said astronomer John Tonry, whose team built the "truly giant instrument" at UH-Manoa's Institute for Astronomy.
The gigapixel camera recently was installed on Pan-STARRS-1, the prototype for an array of four telescopes planned in a Panoramic Survey Telescope and Rapid Response System.
Pan-STARRS is designed to see deep into space and repeatedly survey the sky to track potentially dangerous near-Earth asteroids and other moving objects.
On Monday, for instance, according to NASA, a boulder called 2007 RF2 will pass within 3 million miles of the Earth, a near miss in the realm of astronomy. The rock, traveling at a whopping 46,000 mph, is between 715 and 1,430 feet in diameter, about 10 times the size of the object that created Meteor Crater in Arizona about 50,000 years ago.
But it is the asteroids we don't know about yet that could pose the biggest threat. Finding those objects is one of the principal missions of Pan-STARRS.
The telescope has two mirrors, 6 feet and 3 feet in diameter, and three lenses, each about 2 or 2.5 feet across.
The detector operates like a digital camera, Tonry said, explaining that it collects light, turns it into an electrical signal, analyzes the signal and puts digital results into a computer file. Tonry said the camera allows the sky's brightness to be measured in 1.4 billion places simultaneously.
The telescope's mirrors, lenses and detector must be perfectly aligned, he said, adding that the process of bringing them into alignment will take months.
But results already are "truly, truly quite outstanding," he said, comparing the data output to "a DVD movie you might watch. We will be collecting a DVD movie's worth of information about every minute."
The Maui High Performance Computer Center is hosting more than 100 computers that the Pan-STARRS team will operate for the data, Tonry said.
The scientists will examine each image for changes that could indicate a previously undiscovered asteroid. Data will be combined from images, the orbit of an asteroid calculated and warning messages sent if any object threatens Earth.
The system also will be used to map the solar system.
"It's really fun," Tonry said. "We can get the best of both worlds when looking at pretty things in the sky. We can look at pretty nebulae that you see on posters, or a full moon. But at the same time, this is a no-compromise astronomical quality instrument."
The silicon chips in the Pan-STARRS camera were developed with Lincoln Laboratory of the Massachusetts Institute of Technology. They contain advanced circuitry that makes instant corrections for any image shake caused by the Earth's turbulent atmosphere, the Institute for Astronomy said.
The image area, about 16 inches across, contains 60 identical silicon chips, each with 64 independent imaging circuits.
An institute team led by electronics engineer Peter Onaka developed an ultrafast 480-channel control system to handle the massive data expected from the camera. Astronomer Eugene Magnier led another group that designed software capable of analyzing the thousands of gigabytes of data produced nightly.
PS1 on Haleakala is testing technology but is "a real science production machine" that will operate three years, Tonry said. "Simultaneously, we are building a four-telescope system for Mauna Kea."
The UH 88-inch telescope site on Mauna Kea is considered the best place for the full-scale Panoramic Survey Telescope and Rapid Response System, but site selection is pending completion of an environmental impact statement.
"The intent is that Pan-STARRS will be a little smaller than the 88-inch telescope and we will engineer it to have a much smaller visual impact," Tonry said.