Scientists Improve Hubble without Traveling to Space

By calibrating the telescope’s camera and spectrometer from the ground, scientists have advanced its science capabilities.

Brittany Sauserarchive page

March 26, 2009

The Hubble Space Telescope, one of NASA’s Great Observatories and a vital research tool, is scheduled to undergo a final servicing mission in May, but scientists at Rochester Institute of Technology felt no need to wait until then to improve the telescope’s imaging capabilities. Led by Dan Batcheldor, scientists devised a nine-orbit calibration plan to recalibrate Hubble’s near-infrared camera and multi-object spectrometer when the instruments’ calibrations were stalling Batcheldor ‘s investigation of active galactic nuclei.

The instruments are vital for researchers because they enable high-precision polarimetry, a technique to see around clouds of dust and gas and into the center of active galactic nuclei and the potential planet-forming disks around young stars. “Polarimetry is really quite a powerful tool in astronomy because it can essentially see around corners by the way light is reflecting,” said Batcheldor in a press release. “When you do polarimetry what you are essentially looking through is a set of polaroid sunglasses. What a polaroid does is it makes you see only light aligned in a certain way.”

From the press release:

This false-color image of Uranus surrounded by its four major rings and by 10 of its 17 known satellites was taken August 18, 1998, using Hubble’s near-infrared camera and multi-object spectrometer. Credit: NASA/JPL/STScI

Recalibrating the Near-Infrared Camera and Multi-Object Spectrometer was what Batcheldor describes as something of a “nightmare.” His team devised a program that could choreograph three different filtered observations of a single star at different orientations and switch between cameras within 45-minute fly-bys. “Essentially, we made Hubble chop all over the sky very quickly to get these observations,” he says.

Scientists at the Space Telescope Science Institute verified the calibration plan would work and gathered the observations over 12 months.
“We’ve been able to take an existing camera and carefully plan some observations, which have allowed us to enable a new type of science to be done without having to go up to the telescope to put a new instrument in,” Batcheldor says. “So for a very small cost, we’ve been able to expand the science that the Hubble Space Telescope can do.”

The calibration advance is separate from the final servicing mission but remains a significant improvement to the telescope. NASA hopes to expand the life of Hubble until at least 2013, when the James Webb Space Telescope is schedule to be deployed.