Producing Astrophotographic Knowledge: Glass Plate Photography in Dutch Astronomy, 1890–1960

The development and implementation of glass plate photography profoundly impacted the daily practice of observational astronomy. This impact is especially clear in the case of Leiden Observatory, which managed to rise to prominence in photographic astronomy during the period 1920-1960, despite both the climate and the terrain being unfavourable for optical observations. Leiden Observatory still houses over 40,000 photographic plates with the markings and annotations still intact. This wealth of material makes it possible to reconstruct in detail how these plates were taken, transferred, and reduced in produce astronomical knowledge. This project traces the entire process of glass plate astrophotography, including how photographic projects were planned and requested, how the plates were then taken and transferred, and finally how they were measured and reduced.

Leiden and Johannesburg

One of the ways in which the Leiden astronomers compensated for the poor observational conditions in the Netherlands was by importing photographic plates from foreign observatories. In particular, they had a long lasting collaboration with Union Observatory in Johannesburg, whereby one of the Leiden observers would be stationed in Johannesburg to take photographic plates for transport to the Netherlands. In total, over 20,000 plates to shipped from South Africa to Johannesburg. What were the social-historical circumstances that led to this collaboration?

Leiden Computers

Leiden Observatory had a considerable staff that worked on the photographic plates, but a considerable number of them were not formally considered astronomers but were hired as computers. The contributions these Leiden computers remains unstudied and as a result almost nothing is known about who they were and what they did. This projects corrects this gap in our knowledge by investigating the lives and work of these computers. In doing so, it highlights their contributions and illustrates the division of labour that existed within Leiden Observatory.

This project is funded by the German Research Foundation (DFG), as part of the project:
Astronomy’s Glass Archive: Photographic Practices at the Observatory, 1850-1950 (446722167)