Integrating AO in a performance budget: towards a global systemengineering vision

摘要

EAGLE (Extremely large Adaptive telescope for GaLaxy Evolution) is one of the eight E-ELT instrument concepts that were developed as p art of the Phase A E-ELT instrument studies. EAG LE is a near-infrared wide field multi object spectrograph[4]. It includes its own multi-object adaptive optics system (MOAO) and its subsystems are cooled down so as to ens ure th at t he i nstrument ca n both ac hieve t he des ired s patial res olution a nd to be s ure t hat t he i nstrument i s background limited, as required in the primary science case, to deliver the performance in the K-band. In this paper we discuss the performance matrix developed to allow us to partition and allocate the important characteristics to the various subsystems as well a s to d escribe th e p rocess to v erify th at th e c urrent co ncept d esign will d eliver th e r equired performance. Du e to th e integrated nature of the instrument, a large number of AO parameters have to be controlled. The performance matrix also has to deal with the added complexity of active and adaptive optical elements such as the science channel deformable mirrors (DMs). This paper also defines a method of how to convert the ensquared energy (EE) and signal-to-noise ratio (SNR) required by the science cases into the "as designed" wavefront error and the overall residue wavefront error. To ensure successful integration and verification of the next generation instruments for ELT it is of the utmost importance to have method to control and manage the instrument's critical performance characteristics at very early design steps.