Adaptive Optics Specification for a 10m Telescope on the ORM

The Spanish astronomical community has decided to build a 10m telescope employing a segmented primary mirror in the Observatorio del Roque de los Muchachos (ORM) on the island of La Palma in the Canary Islands. The telescope will incorporate an Adaptive Optics (AO) facility and work is underway to specify the requirements for this system. The AO requirements are being drawn up at this early stage so that they may be taken into account in the detailed optical and mechanical design of the telescope. In particular, the ability to carry out AO at the shortest wavelengths feasable should not be limited by errors in the phasing and tilting of the primary mirror segments. The form of the PSF and the Strehl ratio dependance on these errors is examined by Fourier transforming a simple simulation of the segmented mirror. The simulation includes inter-segment correlation of the piston errors.