Opto-mechanical design of GRAVITY+ wavefront sensor

Abstract

The GRAVITY+ project consists of instrumental upgrades to the Very Large Telescope Interferometer (VLTI) for faintscience, high-contrast, milliarcsecond interferometric imaging. As an integral part of the GRAVITY+ Adaptive Optics (AO) architecture, the Wavefront Sensor (WFS) subsystem corrects image distortions caused by the turbulence of Earth's atmosphere. We present the opto-mechanical design of the WFS subsystem and the design strategies used to implement two payloads positioned diagonally opposite each other -Natural Guide Star (NGS) and Laser Guide Star (LGS) -within a single compact design structure. We discuss the implementation of relative motions of the two payloads covering their respective patrol fields and a nested motion within the LGS Payload covering the complete Sodium layer profile in the Earth's atmosphere.