Radical Antarctic Telescope Would Outdo Hubble

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.

Tests by a team from the University of New South Wales, reported in the
journal Nature this week [16 September], 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.

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.”

IMAGES

Available at ftp://ftp.aao.gov.au/pub/local/will/what/

Concept overview
Small (25 K)
ftp://ftp.aao.gov.au/pub/local/will/what/what-spie-overview_150.jpg

Medium (235 K)
ftp://ftp.aao.gov.au/pub/local/will/what/what-overview_horiz.jpg

Large (591 K)
ftp://ftp.aao.gov.au/pub/local/will/what/what_overview_horiz3.jpg

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

Telescope corrector

Small (29 K)
ftp://ftp.aao.gov.au/pub/local/will/what/what_corrector_horiz_150.jpg

Large (820 K)
ftp://ftp.aao.gov.au/pub/local/will/what/what_corrector_horiz3.jpg
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

Animation (17 MB avi file)
ftp://ftp.aao.gov.au/pub/local/will/what/what-spie.avi
Credit: Andrew McGrath, AAO

REFERENCE

Lawrence J. S., Ashley M. C. B., Tokovinin A. & Travouillon T. Nature,
431. 278 – 281 (2004).