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Salt First Science

Media Invitation: First Science with SALT
First there was SALT First Light (September 2005), when the first colour images of the Southern African Large Telescope (SALT) were released to the national and international public, exactly five years after groundbreaking.
Then, in November last year there was the official inauguration of Southern Africa’s Large Telescope in Sutherland by President Thabo Mbeki, signalling that Africa’s giant eye to the sky was ready for business.

Now, for the first time, SALT’s first significant scientific research results are about to be released to the general public and the international science community – amongst other things giving new insight into an exotic pair of stars closely orbiting one another...
This research uses a strength of the SALT design which is rare among large telescopes, the ability to take 'snapshots' of stars in very quick succession, so that the rapidly changing properties of compact stars can be studied, especially as they pull in gas from their companions or surroundings.
Media Invitation

WHERE: Auditorium, South African Astronomical Observatory,
Observatory Road, Observatory, Cape Town

TIME: 10:30 for 11:00, Wednesday, 16 August 2006.


The release of the SALT First Science information coincides with the 26th General Assembly of the International Astronomical Union (IAU). The science of astronomy has certainly never been more interesting - astronomical discoveries are pouring in from observatories on the ground and in space, and notably for the first time from SALT.

-- Edited by Blobrana at 23:54, 2006-08-15



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Title: The NIR Upgrade to the SALT Robert Stobie Spectrograph
Authors: Andrew I. Sheinis, Marsha J. Wolf, Matthew A. Bershady, David A.H. Buckley, Kenneth H. Nordsieck, Ted B. Williams

The near infrared (NIR) upgrade to the Robert Stobie Spectrograph (RSS) on the Southern African Large Telescope (SALT), RSS/NIR, extends the spectral coverage of all modes of the visible arm. The RSS/NIR is a low to medium resolution spectrograph with broadband imaging, spectropolarimetric, and Fabry-Perot imaging capabilities.
The visible and NIR arms can be used simultaneously to extend spectral coverage from approximately 3200 A to 1.6 um. Both arms utilize high efficiency volume phase holographic gratings via articulating gratings and cameras. The NIR camera is designed around a 2048x2048 HAWAII-2RG detector housed in a cryogenic dewar. The Epps optical design of the camera consists of 6 spherical elements, providing sub-pixel rms image sizes of 7.5 ±1.0 um over all wavelengths and field angles.
The exact long wavelength cutoff is yet to be determined in a detailed thermal analysis and will depend on the semi-warm instrument cooling scheme. Initial estimates place instrument limiting magnitudes at J = 23.4 and H(1.4-1.6 um) = 21.6 for S/N = 3 in a 1 hour exposure well below the sky noise.

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RE: Salt First light

All sky Webcam at the Sutherland observing station of the South African Astronomical Observatory.



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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.



Posts: 131433

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.


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.


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

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