Huge New South Africa Telescope (frm Wash. Post)

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Telescope May Find Light From Earliest Galaxies

By Charlie Schmidt
Special to The Washington Post
Monday, April 24, 2006; A06



Last November, a thousand people gathered in South Africa's Great Karoo
desert to inaugurate the Southern Hemisphere's largest optical telescope.
Champagne flowed under azure skies as mingling guests snapped photos of the
gleaming white structure, perched starkly against the barren landscape.
President Thabo Mbeki gave the keynote address, paying homage to the "Great
Eye in the Karoo" and its power to "tackle fundamental questions about the
universe."

To its creators, the fanfare was befitting the event: The Southern African
Large Telescope, or SALT, can see 13 billion years back in time, nearly to
the big bang.

With its 10-by-11-foot hexagonal mirror -- the largest of its type in the
world -- SALT concentrates the faintest, most distant light in the universe.
If a candle were to flicker on the moon, SALT could detect it.

"One of the hottest things going in astronomy right now is [studying] light
remnants from the earliest galaxies, and SALT is very well set up to do
that," said Steve Maran, spokesman for the American Astronomical Society.

More than a tool for astronomy, SALT also symbolizes the growing importance
of science to South Africa's identity and economy. When the African National
Congress won power in 1994, its leaders inherited a science infrastructure
created by the apartheid government to sustain white minority rule. Isolated
by economic sanctions, that government used science to promote
self-sufficiency and defense, said Dhesigen Naidoo, deputy director general
of South Africa's Department of Science and Technology: "We decided to build
on that but also to change the objectives."

Instead of serving a ruling minority, science aims to serve all 45 million
inhabitants, Naidoo said. South Africa spends nearly 1 percent of its gross
domestic product on science -- about five times the African average.
Reflecting its needs as a developing country, much of that goes toward
research in agriculture, health and biotechnology. But astronomy also plays
a crucial role in the national research and development strategy, said Derek
Hanekom, deputy minister of science and technology, because it draws global
collaborators and because it inspires the population, particularly the
young.

"When you show young people the telescope, they really seem to get it," he
said. "SALT makes them want to get into science. You can't underestimate
that in a country where science and math education were systematically
neglected."

From its perch in the Great Karoo, far from interfering light pollution,
SALT's view of the southern sky is practically unbeatable. The telescope
sits in the middle of nowhere -- the nearest town, a frontier outpost called
Sutherland, is more than 10 miles away.

"At night with a new moon, you can't even see your feet," said Kenneth
Nordsieck, an astronomy professor at the University of Wisconsin and a
principal investigator at SALT. "But then you look up at the sky and see the
Magellanic Clouds, and it's just awe-inspiring."

Other Southern Hemisphere telescopes, including those in Chile, have views
of the same celestial regions. But SALT's enormous light-gathering capacity
and innovative design features offer advantages for certain types of
research, Nordsieck said.

To save money, SALT's view of the sky is fixed -- astronomers can't point
the telescope at specific objects in space. Instead, they wait for Earth's
rotation to bring the bodies they want to study past the telescope's eye.

As a result, astronomers will use SALT for large-scale surveys of thousands
of stars and galaxies within the telescope's field of view.

"Surveys tell you how individual stars and galaxies fit into a larger
picture," Nordsieck said. "There's great interest among astronomers in how
the strange-looking objects we see at great distances, which were present at
the beginning of the universe, turn into the galaxies and stars of today."

Nordsieck designed SALT's main instrument: the Robert Stobie Spectrograph
(named after the late director of the South African Astronomical Observatory
that runs SALT), which splits light into its component wavelengths, or
spectra.

Unlike those on most other telescopes, SALT's spectrograph has a
"polarimetric mode" that allows for observations in the ultraviolet range.
This makes it possible to investigate magnetic fields surrounding stars and
galaxies, and to measure features that can't ordinarily be seen, such as the
shapes of exploding stars and the trajectories of luminous gases and dust.

The spectrograph also has a unique high-speed mode that can reveal, for
instance, how particles behave just before being sucked into black holes.
"These are the kinds of data that could allow us to test Albert Einstein's
theory of relativity," said Phil Charles, SALT's director. "And that's one
of our ultimate goals."

SALT astronomers are preparing to start construction of a second
spectrograph, which will complete the telescope's initial suite of
instruments. This $2.5 million high-resolution device will offer even more
precise spectral measurements. It was designed by a group led by Peter
Cottrell of the University of Canterbury in New Zealand and is scheduled to
arrive in South Africa in 2008. This instrument is expected to be able to
detect motions of just a few meters per second, such as those produced by
unseen planets pulling on their host stars.

With it, astronomers will be able to hunt for new planets, which is big
business in astronomy, noted Alex Wolszczan, professor of astronomy and
astrophysics at Pennsylvania State University.

Charles said it could be a year before SALT becomes fully operational. But
the telescope has produced its "first light" images, including pictures of
the Lagoon Nebula, a giant interstellar cloud 5,200 light-years from Earth;
and 47 Tucanae, a spectacular cluster of 100,000 stars thought to be among
the oldest in the universe.

SALT is already a boon for South Africa. It was built by a six-nation
consortium, with South Africa as the leading member with a one-third share.
The project's foreign partners paid two-thirds of the $20 million cost, and
most of that was spent in South Africa, Naidoo said.

"Instruments like those on SALT are rare, so the best astronomers in the
world are coming to South Africa to work," he said. "And they're helping us
train our own next generation of astrophysicists. Ten years ago, a black
scientist in a major institution like SALT would have been unheard of in
South Africa. Now that's a reality. So, this has the broader impact of
empowering a nation -- of helping people with a history of oppression make
the transition to being normal citizens in society."

© 2006 The Washington Post Company

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By Charlie Schmidt
Special to The Washington Post

With its 10-by-11-foot hexagonal mirror

Not quite -- it is 10-by-11 meters (32-by-36 foot).