A user-friendly way to optimize adaptive optics: NAOS Preparation Software

Stephane Marteau (Observatoire de Meudon), David Mouillet (Observatoire de Grenoble), Laurent Rousset-Rouviere (ONERA), Gerard Zins (SHAKTI)Didier Rabaud (ONERA)Jean-Marc Conan (ONERA)Eric Gendron (Observatoire de Meudon)Gerard Rousset (ONERA)Norbert Hubin (ESO)Francois Lacombe (Observatoire de Meudon)Anne-Marie Lagrange (Observatoire de Grenoble)

Abstract:

The preparation of observations to be carried out with adaptive optics (AO) systems is more complex than with other instruments, for the following reasons:

• the number of parameters to set is larger than for a simple imager or even a spectrograph. Furthermore, these parameters concern the algorithm which is used to optimize the corrected beam and are, a priori, unfamiliar to most observers, while critical for the performance.
• optimizing the instrumental configuration for a given observation highly depends on external conditions, such as the reference object used to close the AO loop, and the turbulence condition in the atmosphere.
• the main scheduling criterion is the achievable performance, in terms of Strehl ratio, and there is of course not a one-to-one relation between this criterion and the configuration of the AO system.

In this paper, we will go into details of the NAOS Preparation Software (PS), which aims to provide the astronomer with a unified interface for everything that pertains to the preparation of the adaptive optics system, from the choice of the reference object to the setting of the needed parameters. We will show how this interface does not make any assumptions on the expertise level of the user, i.e. that it is simple enough for non-specialists, while also enabling AO experts to tune the system at their will, should they want to do so. We will describe the remote preparation phase which is performed through a standard web browser, via a dedicated interface. The tool is to be available during the program preparation phase, but will also be requested during the observation itself, for on-line performance estimation and possible re-optimization of the AO system. We will also detail the core of the software, aka "PS Server", made of a Configuration Optimizer and a Performance Estimator. The former enables to choose the best suitable configurations according to the current assumptions about the external parameters (atmosphere, reference object). The result of this analysis is then processed by the latter, which simulates the behaviour of the adaptive optics in such conditions, and returns an estimation of the expected image.