Dr Kenneth J. Johnston (United States Naval Observatory, Washington DC)

Space Astrometry: Past and Future Missions - Dr Kenneth J. Johnston Colloquium

ATNF Marsfield Lecture Theatre

Abstract

Space offers orders of magnitude improvement in astrometric accuracy leading to advances in all fields of astrophysics. Precise knowledge of position, parallax and proper motion allows determination of fundamental quantities. The Hipparcos mission, which flew in the early 1990's,improved astrometric accuracy over large angles from 100 to 1 milliarcseconds. Missions proposed in the late 1990s promise a further two or three orders of magnitude improvement. These missions and the science to be accomplished with them will be discussed.