Mapping Distortion of Detectors in UVIT Onboard AstroSat Observatory

TL;DR

This paper details the methodology for estimating and correcting detector distortions in UVIT on AstroSat to improve astrometric accuracy in multi-wavelength ultraviolet imaging.

Contribution

It introduces a new calibration approach for quantifying and correcting detector distortions in UVIT's intensified imagers.

Findings

Distortion correction improves image accuracy

Calibration methodology is effective for ground-based adjustments

Enhances the scientific utility of UVIT data

Abstract

Ultraviolet Imaging Telescope (UVIT) is one of the payloads onboard AstroSat, India's first multi-wavelength Astronomy mission. UVIT is primarily designed to make high resolution images in wide field, in three wavelength channels simultaneously: FUV (130 - 180 nm), NUV (200 - 300 nm) and VIS (320 - 550 nm). The intensified imagers used in UVIT suffer from distortions, and a correction is necessary for these to achieve good astrometry. In this article we describe the methodology and calculations used to estimate the distortions in ground calibrations.