AO4ELT5 Proceedings

ELT Pre-Focal Station NGS Sensor Arm

La Penna, Paolo (European Southern Observatory)

Each Nasmyth platforms of the ELT will host one Prefocal Station, which main function will be to provide a first control of the telescope shape, before delivering the light wavefront to the instruments. Besides providing three Nasmyth focal planes and one Coudé focus, each PFS will include three Natural Guide Star Sensor Arms, rotating on an adapter, to support the low order optimization and control of the telescope shape in seeing limited image quality. Each Sensor Arm will include an image channel, to perform guiding and telescope tip-tilt tracking, and a wavefront sensor, to correct higher order modes. In this paper an opto-mechanical concept of the Sensor Arm is reported.

DOI: 10.26698/AO4ELT5.0018- Proceeding PDF


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