Instrumentation for infrared astronomical observations at the Tata Institute of Fundamental Research, Bombay

Abstract

A programme was initiated at the Tata Institute of Fundamental Research in 1973 to develop infrastructural facilities for undertaking observations in the field of far-infrared astronomy (λ > 20 μm), which can only be carried out from above most of the earth's atmosphere. A telescope of 30 cm aperture was developed using a wide field of view, followed up with the design and fabrication of two balloon-borne telescopes, a three-axes stabilized 75 cm telescope and one of 100 cm aperture, both having a pointing accuracy better than 0.5 arc min. A single band photometer (for a 76 - 116 μm or 120 - 300 μm band) and a double band photometer (45 - 75 μm and 110 - 210 μm bands) and two near-infrared photometers have been developed. In addition to the instruments for astronomical observations, some instruments, suitable for monitoring the quality of astronomical sites have been developed. The essential features of these instruments are described and some of the astronomical observations carried out using them are outlined.