44. Astronomy from Space L’Astronomie à Partir de L’Espace

Abstract

The 1987-90 triennium has been a prosperous one for space astronomy. The field has benefited from diverse activities, ranging in style from the continued operation of some old instruments, such as uv spectrographs aboard IUE and Voyager, to the introduction of completely new observing techniques, such as the Hipparcos mission to perform astrometry over large angles and the radio Very Long Baseline Interferometry (VLBI) demonstration with the NASA’s Tracking and Data Relay Satellite System (TDRSS). We have witnessed some important highlights in space astronomy which significantly enhanced our understanding of some fundamental problems in astrophysics. For instance, the COBE satellite offered a tremendous gain in the precision of measuring the cosmic background radiation, and initial results seem to authenticate the simple character of this microwave radiation. As noted in the previous report of Commission 44, Supernova 1987A in the Large Magellanic Cloud was the brightest supernova since the one sighted by Kepler in 1604. There have been remarkable improvements in astronomical instruments since Kepler’s time, and the fruits of our good fortunes with 1987A are now appearing in the literature. Finally, the long anticipated launch of our biggest enterprise in space astronomy, the Hubble Space Telescope, occurred in the spring of 1990.