Hubble gets a camera upgrade

17 Jun 2002

New optics will allow the space telescope to look further into the infrared and therefore further back in time.

Astronauts have fitted a new camera in the Hubble Space Telescope (HST). The Advanced Camera for Surveys (ACS), will double the instrument's observational area and resolution, and quadruple its sensitivity.

The ACS operates from the ultraviolet region, through the visible and into the near-infrared. It replaces the Faint Object Camera, which was the last of Hubble's original instruments.

With a new set of polarizers, filters and dispersers, the ACS can see deeper into the infrared region. This means that red-shifted light from very distant objects can now be detected, and that the HST can effectively look further back in time at a younger universe.

Team leader Holland Ford, of The Johns Hopkins University, said of the new camera: "If you had two fireflies six feet apart in Tokyo, the ACS could view them from Washington and tell that they were different flies."

The ACS is actually three cameras in one. It consists of a wide-field camera, a high-resolution camera and a solar-blind camera sensitive to ultraviolet light.

Once the instrument is calibrated, researchers should be able to perform projects such as a deep-field survey, where a particular part of the sky is studied in great detail, much more quickly. These surveys normally take 20 days, and should now be reduced to around two days.

As well as looking at distant, faint objects, the ACS will be checking out the sun's stellar neighbours - Alpha Centauri A and B - to look for any small planet-like objects orbiting them.

Ford thinks that there is an outside chance that the ACS could obtain direct evidence of planets in nearby solar systems. "It's going to be difficult, for sure, but we're going to try it," he said.

Extra-solar planets have been detected around many stars, but their existence tends to be inferred from a gravitational "wobble".

The first pictures from the upgraded HST are expected in around two months, after the ACS calibration is completed.

Author
Michael Hatcher is technology editor of Opto & Laser Europe magazine.