The History of Astrometry

TL;DR

This paper reviews the extensive history of astrometry, highlighting its evolution from ancient observations to space-based measurements, and its crucial role in understanding the universe's scale, structure, and fundamental physics.

Contribution

It provides a comprehensive historical overview of astrometry, emphasizing technological advances and their impact on astronomical and scientific discoveries over two millennia.

Findings

Progressed from early celestial position records to space-based high-precision measurements

Enabled accurate measurements of stellar distances and galactic structure

Significantly advanced understanding of the universe's scale and physical properties

Abstract

The history of astrometry, the branch of astronomy dealing with the positions of celestial objects, is a lengthy and complex chronicle, having its origins in the earliest records of astronomical observations more than two thousand years ago, and extending to the high accuracy observations being made from space today. Improved star positions progressively opened up and advanced fundamental fields of scientific enquiry, including our understanding of the scale of the solar system, the details of the Earth's motion through space, and the comprehension and acceptance of Newtonianism. They also proved crucial to the practical task of maritime navigation. Over the past 400 years, during which positional accuracy has improved roughly logarithmically with time, the distances to the nearest stars were triangulated, making use of the extended measurement baseline given by the Earth's orbit around the Sun. This led to quantifying the extravagantly vast scale of the Universe, to a determination of the physical properties of stars, and to the resulting characterisation of the structure, dynamics and origin of our Galaxy. After a period in the middle years of the twentieth century in which accuracy improvements were greatly hampered by the perturbing effects of the Earth's atmosphere, ultra-high accuracies of star positions from space platforms have led to a renewed advance in this fundamental science over the past few years.