Proposed UV - optical payload for the Indian astronomy satellite

Abstract

The Ultraviolet Imaging Telescope is a part of the proposed Indian Multiwavelength Astronomy Satellite mission. The primary objective of the UV Imaging Telescope is an all-sky survey in two bands in the wavelength region 1200 to 3000 Angstrom. The aperture of the telescope will be 50 cm and there will be two channels for simultaneous observations, one for the range 1200-1900 Angstrom and the other longwards of 1800 Angstrom. The goal for spatial resolution on the sky over a full field of 2 Angstrom is ~ 2 seconds of arc. The detectors of choice are photon counting devices using MCP intensifiers and different photocathodes for the two channels. Each channel will have a filter changing mechanism, with a provision for upto 4 full size filters and 20 small (20 arc minutes) filters. It will also be possible to mount grisms for field spectroscopy. The all-sky survey is expected to reach a UV (1500 Angstrom)limiting magnitude of 20. After the all sky survey, deeper surveys over selected regions of the sky can also be done, interspersed with programs for the X-ray payload. A key area will be simultaneous UV/optical and X-ray observations of a variety of astronomical objects ranging from binaries to quasi-stellar objects and active galactic nuclei. The launch of the mission is expected between the years 2002 and 2004.