Analysis of the differential distortions in multiconjugate adaptive optics-assisted astronomical instruments: the MAVIS perspective

The rapid advancement of adaptive optics systems requires improved or novel methods for performance testing and verification. In the new era of a stronomical instrumentation, achieving high-resolution imaging and high-precision astrometry is a primary objective. One of the key factors influencing these capabilities is optical distortion. In this paper, we present a methodology for analyzing differential distortion in multi-conjugate adaptive optics (MCAO) instruments, in the context of the MCAO-Assisted Visible Imager and Spectrograph (MAVIS) for the Very Large Telescope (VLT). Specifically, we investigate the differential distortions that arise between the Natural Guide Star (NGS) wavefront sensors and the science channel. We examine the impact of the moving components of MAVIS - such as the K-mirror and the atmospheric dispersion corrector - on the distortions observed in the science focal plane. The findings of this study will contribute to the development of a robust calibration strategy for MAVIS.