  The Ultra-Violet Imaging Telescope (UVIT) is one of the payloads in ASTROSAT,
the first Indian Space Observatory. The UVIT instrument has two 375mm
telescopes: one for the far-ultraviolet (FUV) channel (1300--1800\AA), and the
other for the near-ultraviolet (NUV) channel (2000--3000\AA) and the visible
(VIS) channel (3200--5500\AA). UVIT is primarily designed for simultaneous
imaging in the two ultraviolet channels with spatial resolution better than 1.8
arcsec, along with provision for slit-less spectroscopy in the NUV and FUV
channels.The results of in-orbit calibrations of UVIT are presented in this
paper.
