Interviews about modern astrometry

TL;DR

This paper presents interviews with key scientists involved in the Hipparcos and Gaia astrometry missions, discussing the historical development, technological choices, and future prospects of modern astrometry.

Contribution

It provides detailed personal insights and historical context on the evolution of astrometry from 1980 onward, including technical decisions behind Gaia's design.

Findings

Historical overview of astrometry development

Technical insights into Gaia mission design

Reflections on future astrometry directions

Abstract

Michael Perryman has interviewed some of the scientists and project leaders in the Hipparcos and Gaia missions, the interviews with photos of the persons are given at his site: https://www.michaelperryman.co.uk . Michael has also written essays -- 84 to date ! -- about results from the Gaia mission and they are placed at his site. Three of the interviews are with me and transcriptions, co-authored with Michael, are provided below with the titles: #1. An interview about astronomy and astrometry up to 1980. #2. An interview about the revival of astrometry after 1980. #3. The billion-star astrometry after 1990. The third interview begins in 1990 when I had the first ideas for a Hipparcos successor. In 1992 I made a detailed design with direct imaging on CCD detectors in a satellite proposal called Roemer. In 1993 a supposedly better option was proposed with the acronym GAIA where the capital "I" stood for Interferometer. In 1998, however, interferometry was shown to be unsuited for the purpose and we returned to the original idea from 1992 for the further development. The name was later changed to Gaia -- for the sake of continuity.