* Astronomy

Blobrana · L

Salt First Science

Blobrana · L

SALT

Blobrana · L

RE: Salt First light

Blobrana · L

In the beginning all was smooth. And now all is scattered.
How this process unfolded long ago is one of the secrets scientists hope to unlock with the Southern African Large Telescope (SALT) which was launched in a remote corner of South Africa's Karoo region on Thursday.

"SALT gives us the ability to look far back in time" - Dr. David Buckley, the project scientist.

The light from the objects that SALT will probe was emitted billions of years ago, giving us an eye on the distant path and the evolution of the universe.

"When the universe was very young it was smooth and had a uniform distribution but now it is quite clumpy. You look at the night sky and the stars are scattered all over the place. We want to find out how this happened" - Dr. David Buckley.

Looking at the night sky from the windswept hillside where SALT is located gives one an idea of how scattered things are out there.
The location 400km from Cape Town is widely regarded as one of the best on our own planet for exploring distant worlds.
SALT will also probe far off black holes which are sucking in matter spinning around them -- terrifying things.

"Whatever goes into a black hole doesn't come out" .

SALT is also able to capture rapid images of stars and other objects in a constant process of change.

"Unlike other large telescopes which take snapshots, SALT has a detection system akin to a video camera. It can take 10 to 20 frames per second" - Dr. David Buckley.

This is important because some objects in the universe can vary and change on that kind of time scale.
SALT will be put to use in the search for planets in solar systems far from our own.
With a diameter of 11 meters, SALT is the largest single telescope in the southern hemisphere and cost around $30 million to build. It resembles a massive honeycomb which is filled with 91 smaller honeycombs.

Blobrana · L

The first colour images taken by the largest optical telescope in the southern hemisphere - some of constellations as distant as 10 000 million light years - were revealed on Thursday by the astronomy team responsible for the Southern African Large Telescope (Salt) located near the chilly Karoo town of Sutherland.

WEBCAM

Nicknamed "Africa's giant eye", the telescope gathers more than 25 times as much light as any existing African telescope and is powerful enough to detect objects as faint as a candle flame on the moon.
It is designed to withstand winds of 220km/h in a building nearly 30 metres in height and diameter.
The primary mirror, which is the key to the might and sophistication of the telescope, has 91 interchangeable hexagonal mirror segments aligned to form a spherical figure like a honeycomb, each of which weighs approximately 100kg. The mirror is 11m across.

WEBCAM

The mirror collects light from distant stars and galaxies. It replaces the lens from early 20th century telescopes, such as the one from 1901 in the dome at the South African Astronomical Observatory, which has a 60cm diameter lens and was the most sophisticated of its time.
Unlike the largest twin telescopes in the northern hemisphere, situated in Hawaii, Salt is able to use its full mirror which technically makes it the largest telescope in the world.

One of the images illustrates a green glowing lagoon Nebula. Not to be outdone, another image illustrates the galaxy NGC6744 situated 30 million light years away and 150 000 light years across.

Produced by the Salticam digital camera, these first images or "first light" - so named because they are taken with all 91 mirrors and there is a scientific instrument working on the telescope - would improve over the next few months as the telescope was "tweaked" for better performance, according to project scientist David Buckley.

Astronomer Darragh O'Donoghue said, however, that this was a very important moment in the telescope's life as it demonstrated the sorts of images it could produce.
Modelled after the Hobby-Eberly Telescope developed in Texas in the 1980s, salt wound up being a "South African result - not just an American copy", due to design and optics improvements, project manager Kobus Meiring said.

"It was built to persuade young people that first-rate science can happen here and that we in Africa can experience the universe with the best of them" - David Laney, astronomer.

Work on the project - a third of which was paid by South Africa and the rest by its international partners - started five years ago.
The engineering team knew nothing about astronomy when they started the project, having come from backgrounds as diverse as food engineering, aviation and dam building.

"What worked in our favour is that we didn't know what we couldn't do" Kobus Meiring.

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-- Edited by Blobrana at 13:58, 2005-09-02