Astrometry 1960-80: from Hamburg to Hipparcos

TL;DR

This paper traces the development of astrometry from its decline in the mid-20th century to its revival with the Hipparcos satellite, highlighting innovations like photon-counting astrometry and the author's personal contributions.

Contribution

The paper introduces the photon-counting astrometry technique and its successful implementation in Hamburg, which paved the way for space-based astrometry with Hipparcos.

Findings

Photon-counting astrometry proved effective in Hamburg.

The technique was successfully used during the Hamburg expedition (1967-72).

Hipparcos revolutionized astrometry with space-based measurements.

Abstract

Astrometry, the most ancient branch of astronomy, was facing extinction during much of the 20th century in the competition with astrophysics. The revival of astrometry came with the European astrometry satellite Hipparcos, approved by ESA in 1980 and launched 1989. Photon-counting astrometry was the basic measuring technique in Hipparcos, a technique invented by the author in 1960 in Hamburg. The technique was implemented on the Repsold meridian circle for the Hamburg expedition to Perth in Western Australia where it worked well during 1967-72. This success paved the way for space astrometry, pioneered in France and implemented on Hipparcos. This report gives a detailed personal account of my life and work in Hamburg Bergedorf where I lived with my family half a century ago.