Mapping distortion of detectors in UVIT onboard AstroSat observatory
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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.
KeywordsDistortions UV telescope and instrumentation UV imaging Distortion map
The authors would like to thank University of Calgary for providing the grid, IUCAA for providing the IFOSC images of mask/grid, staff of MGKM laboratory for support for IIA images taken with the CPUs and collegues of UVIT instrumentation team for all the necessary help. VG would like to thank Dr Annadurai, Director, ISRO Satellite Centre (ISAC) and Dr Anil Aggrawal, Group Director, SAG, ISAC and Dr Sreekumar, Director, IIA (former GD, SAG, ISAC) for all their encouragement and support.
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