Séminaire LAM: Henri Bonnet (ESO)

Wavefront architecture of the ELT

The ELT Wavefront Control manages the 5 mirrors of the telescope in position and shape and delivers at the interface with the instruments a beam quality compatible with diffraction-limited performance after correction by post-focal AO systems. This is obtained if the spectral distribution of aberrations in the temporal and spatial domains lies within the dynamics of M4, the deformable mirror of the telescope. In this talk, I will present some properties of the ELT aperture, discuss the main components of telescope dynamic disturbances whose spectral distribution exceeds the envelope of the free atmosphere, and describe the elements of the telescope control strategy.