Hum,
Scant news from the Southern African Large Telescope (SALT).

Their last news letter was way back in March...
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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
Date: June 7th

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 Å to 1.6 um. Both arms utilise 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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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.

Attached Images

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Title: First science with SALT: peering at the accreting polar caps of the eclipsing polar SDSS J015543.40+002807.2
Authors: D. O'Donoghue, D.A.H. Buckley, L.A. Balona, D. Bester, L. Botha, J. Brink, D.B. Carter, P.A. Charles, A. Christians, F. Ebrahim, R. Emmerich, W. Esterhuyse, G.P. Evans, C. Fourie, P. Fourie, H. Gajjar, M. Gordon, C. Gumede, M. de Kock, A. Koeslag, W.P. Koorts, H. Kriel, F. Marang, J.G. Meiring, J.W. Menzies, P. Menzies, D. Metcalfe, B. Meyer, L. Nel, J. O'Connor, F. Osman, C. du Plessis, H. Rall, A. Riddick, E. Romero-Colmenero, S.B. Potter, C. Sass, H. Schalekamp, N. Sessions, S. Siyengo, V. Sopela, H. Steyn, J. Stoffels, J. Stoltz, G. Swart, A. Swat, J. Swiegers, T. Tiheli, P. Vaisanen, W. Whittaker, F. van Wyk

Researchers describe briefly the properties of the recently completed Southern African Large Telescope (SALT), along with its first light imager SALTICAM. Using this instrument, they present 4.3 hours of high speed unfiltered photometric observations of the eclipsing polar SDSSJ015543.40+002807.2 with time resolution as short as 112 ms, the highest quality observations of this kind of any polar to date. The system was observed during its high luminosity state. Two accreting poles are clearly seen in the eclipse light curve. The binary system parameters have been constrained: the white dwarf mass is at the low end of the range expected for cataclysmic variables.
Correlations between the positions of the accretion regions on or near the surface of the white dwarf and the binary system parameters were established. The sizes of the accretion regions and their relative movement from eclipse to eclipse were estimated: they are typically 4-7 deg depending on the mass of the white dwarf. The potential of these observations will only fully be realised when low state data of the same kind are obtained and the contact phases of the eclipse of the white dwarf are measured.

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The Southern African Large Telescope (SALT), inaugurated in November 2005, is today releasing its first public research results, giving new insight into an exotic pair of stars closely orbiting one another.

The new SALT results are for a 'polar' binary star system, which contains a compact star called a 'white dwarf' – a star which has used up its original store of nuclear energy, then shrunk to about one millionth of the volume of a star like our sun. In a polar this 'white dwarf' also has a very strong magnetic field, which strongly influences how the hot gases from its relatively ordinary companion reach the white dwarf surface.

<Attachment 1>
This shows a cartoon of your view of the system at the start of eclipse (left) when the red star is just about to block our view of one magnetic pole, labelled Spot 2, and at the end of eclipse (right) when the red star has just uncovered Spot 2.

<Attachment 2>
A sequence of brightness measurements and the evidence for what has just been described can be seen in the sequence. If you look closely, you will see it has a first sudden brightness drop disappearing), followed about 25 seconds later by a second sudden brightness drop. Towards the end of the sequence there are sudden rises in brightness corresponding to the earlier sudden drops as the spots are uncovered. The gas stream between the stars also gives some light, and this accounts for the rounded shape of the bottom of the eclipse.

This sequence of measurements is better than anything that has been obtained before, and SALT's advantages over all other large telescopes for this type of research should allow SALT astronomers to lead in probing the mysteries of these 'cannibal stars'.

Source (PDF)

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Credit SAAO

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First Science with SALT: Pictures


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Credit SAAO

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Way out in the universe a red giant is being mugged by a white dwarf.

And although the battle galactic is happening a staggering 400 light years away, astronomers at the Southern African Large Telescope (Salt) at Sutherland in the Karoo are able to observe the event.
Yesterday, astronomers from the SA Astronomical Observatory said these observations formed the first "serious science" to come out of the telescope, which was inaugurated in November last year.
Darragh O'Donoghue, principle investigator at Salt, has written up the findings with 50 co-authors, which has been accepted for publication in the Monthly Notices of the Royal Astronomical Society.

www.capetimes.co.za

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`Irony` actually does mean `metal like`...