Astronomy Picture of the Day 09-22-04

Explanation: Is it art? Here the paintbrush was the Spirit robotic rover, the canvas was the soil on Mars, and the artists were the scientists and engineers of the Mars Exploration Rover Mission. The picture created was mostly unintentional -- the MERS team was primarily instructing Spirit to investigate rocks in and around Hank's Hollow in a location called Engineering Flats on Mars. After creating the ground display with its treads, the Spirit rover was instructed to photograph the area along with itself in silhouette. Both Mars rovers, Spirit and Opportunity, are now back in contact after an expected radio blackout caused by Mars moving behind the Sun. NASA has also announced that it is extending the rovers missions for six months, so long as they keep working.

Radical Antarctic telescope 'would outdo Hubble'
ANGLO-AUSTRALIAN OBSERVATORY NEWS RELEASE
Posted: September 17, 2004

A novel Antarctic telescope with 16-m diameter mirrors would far outperform the Hubble Space Telescope, and could be built at a tiny fraction of its cost, says a scientist from the Anglo-Australian Observatory in Sydney, Australia.

On the right is the corrector: a nearly flat, steerable reflector. This receives the light from the sky and directs it onto the primary mirror, over at the left. The primary focuses the light onto a prime focus unit lying halfway between the two mirrors. The prime focus unit could be a number of things: a camera, a device that holds optical fibres for capturing the light, or a secondary mirror reflecting the light through a central hole in the primary mirror. Credit: Andrew McGrath, AAO

Tests by a team from the University of New South Wales, reported in the journal Nature this week, show that the Dome C site in the Australian Antarctic Territory is by far the best place ever tested on Earth for doing infrared and optical astronomy.

"A telescope there would perform as well as a much larger one anywhere else on Earth. It's nearly as good as being in space", said Dr. Will Saunders of the Anglo-Australian Observatory.

At the SPIE Astronomical Telescopes and Instrumentation conference in Glasgow in June, Dr. Saunders presented a concept for an unusual telescope that's well matched to the special conditions at Dome C, both in its optical design and in the way it's built.

It looks nothing like other telescopes. Much of it could be built of icecrete-snow compressed to form blocks as hard as concrete - while its mirrors could be made of the glass used for office windows.

Under the superb atmospheric conditions at Dome C this simple telescope could make razor-sharp images of large areas of sky.

This is a nearly flat, steerable reflector. It receives the light from the sky and directs it onto the telescope's primary mirror. Credit: Andrew McGrath, AAO

Dr. Saunders estimates that his design would cost about a fifth as much as one of the extremely large telescopes now being planned. These have mirrors 30-100 m in diameter and price tags of US$700 million and up. The Hubble Space Telescope cost a few times more: about US$2.2 billion at launch.

"With this simple telescope you could do the exquisite imaging that the extremely large telescopes plan to do, at a fraction of their cost" Dr. Saunders said. "But, unlike them, this telescope would also be a great survey instrument, able to map the whole sky with Hubble-like clarity."

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