MAVIS: preliminary design overview of the natural guide star wavefront sensor submodule

The paper describes the design of the NGS WFS sub-module of MAVIS, an instrument for the VLT UT4 that aims to provide diffraction limited imaging and spectroscopy at visible wavelengths. In this framework the NGS WFS provides means for the tomographic measurement of the lower-orders of the atmospheric turbulence allowing MAVIS to reach the required performances in terms of sky coverage and resolution. We present the optical design and performance of the NGS WFS probes and acquisition camera, the actuators embedded in the subsystem and their control hardware. Finally, we show the mechanical arrangement of the submodule.