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 Netherlands, which managed to rise to prominence in optical astronomy during the period 1890-1960, despite both the climate and the terrain being unfavourable for optical observations. Dutch astronomers compensated for these conditions by importing photographic plates from foreign observatories and measuring them in the Netherlands. This project aims to trace 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. For this research, I will focus primarily on two astronomical institutions, the so-called Astronomical Laboratory in Groningen, and the Leiden Observatory.

The Astronomical Laboratory played an important role in the history of astrophotography as one of the first institutes specifically founded to reduce photographic plates taken elsewhere. Moreover, the successful collaboration between the Astronomical Laboratory and the Cape Observatory, which led to the Cape Photographic Durchmusterung, was critical for convincing the astronomical community of the practical applicability of photography to astronomical research. On the basis of archival materials available at Groningen, it becomes possible to investigate the practical constraints and considerations that Jacobus C. Kapteyn and David Gill in Cape Town both faced as they explored the possibilities of photography for positional astronomy.

Unlike in Groningen, the Leiden Observatory, had its own photographic telescope, but this was hardly ever used for astronomical research. For the first few decades, it was only used to investigate the properties of the telescope itself to aid photographic research elsewhere. Like in Groningen, astronomers in Leiden mainly relied on photographic plates imported from other observatories for their own observational research. Tens of thousands of these plates are still stored in Leiden today 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 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)