Colloquium on 24 March 2016
Sutherland seeing conditions and prospects of an Adaptive Optics system for SALT


Title: Sutherland seeing conditions and prospects of an Adaptive Optics system for SALT
Speaker: Laure Catala (SAAO)
Date: Thursday, 24 March 2016
Time: 11:00 - 12:00
Venue: SAAO Auditorium


Ground-based telescopes are all affected by atmospheric turbulence that degrade their image quality. Nowadays most large telescopes are designed with adaptive optics (AO) systems compensating for those undesirable effects and providing near diffraction limited images to the science instruments. The initial design of SALT does not include such a system.

In the framework of my phd thesis I worked on a dimensioning and performance study of an AO system for SALT. In order to perform such a study a good knowledge of the seeing and atmospheric turbulence conditions at the Sutherland site was necessary. Hence, the first part of my work was dedicated to the site characterization, for which I used data from existing instruments, a MASS-DIMM and a SLODAR. I was also involved in the development of a new turbulence profiler instrument, the PBL, in collaboration with a team at the University of Nice Sophia Antipolis (France). I will give a brief overview of the Sutherland site results along with the PBL instrument development in the first part of this talk.
The second and main part of the talk will focus on the AO dimensioning and performance study. In order to evaluate the potential performances of an AO system for SALT I did a number of simulations. Those simulations need 3 sets of input parameters:
1. The site seeing and atmospheric turbulence conditions
2. The telescope parameters
3. The AO system parameters

The two first ones are known from the site characterization study and available telemetry data and telescope design characteristics. The AO system parameters need to be optimized prior to the actual system performance study. As SALT is mainly designed for spectroscopy we focussed our study on the potential improvements in terms of spectroscopic performances. I present here the optimization study of the AO system parameters and the results of the AO simulations on the potential performances of such a system on SALT.
I will conclude with on-going projects related to the SALT AO study and further areas that still need to be investigated.

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