The very first monthly astronomical journal in Germany: The Celestial Police and their structures of communication

By Janna Katharina Müller

Editorial note: Janna Katharina Müller studies the history and theory of science and technology [“Theorie und Geschichte der Wissenschaft und Technik”] at the Technische Universität Berlin. She’s currently working on her Master’s thesis focusing on the emergence and formation of a concept of the newly discovered asteroids between Mars and Jupiter in the first years after their discovery, 1801–1813. The title of her thesis is: “Von Planeto-Cometen und planetarischen Fragmenten. Die Himmels-Polizey und Asteroidenforschung im frühen 19. Jahrhundert.“ In the spring/summer 2021, she completed a remote internship at the GHI Washington, DC.

A while ago, I was preparing for an oral exam in one of my classes about the history of science during the Enlightenment and the early 19th century. We had to focus on one specific discipline or time period and give a short presentation about it. I decided to prepare a talk about the history of astronomy during that given time frame, and as I worked my way through historical surveys, an anecdote about a group of astronomers kept catching my eye: Six German astronomers founded an association in the early 19th century to track down undiscovered planets – and called themselves the “Himmels-Polizey”, the Celestial Police. They did not find any planets, but they did find the first asteroids – ahistorically speaking – and thus formed the prelude for the Minor Planet Research of the 19th and especially the 20th century.

Unfortunately, that was all the information I could initially find. The Celestial Police – what a name! – did not leave my mind completely, however. In fact, when I started considering possible Master’s thesis topics, I returned to the Celestial Police. In this post, I will introduce a digital source corpus that I located online that can be traced back to their work. In subsequent posts, I plan to reflect on my use of digital sources and tools.

One of these six astronomers involved was Franz Xaver von Zach, court astronomer to the Duke of Saxe-Gotha, in what is now Thuringia. Although he did not personally discover an asteroid, the literature attributes to him an important role in facilitating and coordinating the asteroid discoveries and exploration by organizing meetings among astronomers, initiating the formation of an astronomical society (our Celestial Police), and publishing journals, i.e., creating communicative infrastructures. After spending the early 1780s in Paris and London, von Zach became court astronomer to Duke Ernst II in 1786 and helped build the new observatory on the Seeberg near Gotha. In the following years, von Zach led this observatory to high reputation and, among other things, had many astronomers visiting his observatory again and again, so that he is credited with organizing the first ‘Astronomers’ Congress’ in 1798. Another important meeting took place in September 1800, when von Zach was joined by the German astronomers Schroeter, Olbers, and Harding, and the two state officials (and lay astronomers) von Ende and Gildemeister: During this meeting, they decided to establish a society that would be dedicated, among other things, to the search for previously unknown planets. In this society with the official name “Vereinigte Astronomische Gesellschaft” (United Astronomical Society) 18 additional astronomers from all over Europe were invited to divide the area around the ecliptic (apparent course of the sun in front of the background of the fixed stars) into 24 zones à 15° longitude and 7-8° northern and southern latitude, and divide these among the members for survey. Von Zach wrote in 1801 that such a

„[…] streng organisirte, in 24 Departements abgetheilte Himmels-Polizey hofften wir endlich, diesem, unsern Blicken sich so lange entzogenen Planeten, wenn er anders existirt und sich sichtbar zeigt, auf die Spuhr zu kommen.“

“[…] strictly organized Celestial Police, divided into 24 departments, we finally hoped to get to track down this planet, which has eluded our gaze for so long, if it exists otherwise and shows itself visibly.” (von Zach, Monthly Correspondence, June issue 1801)

Seal of the “United Astronomical Society” with its motto: “Non frustra signorum obitus speculamur et ortus” (Not in vain do we observe the sets of the signs of the zodiac and their rises), in Schroeter, 1805.

Von Zach maintained active contacts with astronomers throughout Europe, especially those in the Paris Académie, such as Lalande or Burckhardt. This correspondence, voluminous by the standards of the time, also formed the basis for von Zach’s publishing activities: In 1798, he founded the Allgemeine Geographische Ephemeriden (AGE), which, in contrast to Bode’s famous Astronomisches Jahrbuch, the most important German periodical publication up to that time, appeared monthly and covered not only geographical but also – closely related – astronomical topics. In addition to essays, book and map reviews, he also included excerpts from his correspondence on astronomical observations and calculations. Soon, however, he realized that dealing with both sets of topics in one journal was getting a bit out of hand and that the correspondence part was taking up more and more space. For this reason, he founded the Monatliche Correspondenz zur Beförderung der Erd- und Himmelskunde (Monthly Correspondence for the Advancement of Terrestrial and Celestial Science, short MC) in 1800. The MC, like the AGE, was issued monthly until December 1813. Fortunately, both sources have been digitized by the Thüringer Universitäts- und Landesbibliothek Jena (Thuringian University and State Library in Jena) and are accessible free of charge in their portal journals@UrMEL (here and here). Without this resource, it would not have been possible for me to access these sources in the last months, since not only the archives were closed due to the pandemic until recently, but also travel was discouraged, even within Germany.

In these blog posts, as in my master’s thesis, I will focus on the MC, as it is the more relevant source corpus for my research on the conceptual evolution of the newly discovered asteroids. The texts published in the periodical on mainly astronomical topics were partially (translated) treatises from other publications, and partially also – as the name suggests – complete letters from Zach’s correspondendents, compilations of excerpts from letters on a certain subject area, and summaries from correspondence whose content Zach communicated in a referential manner. It not only covers the period when the first asteroids were discovered and first studied, but also gathers among its authors many renowned astronomers who were interested in and studied the new celestial bodies, besides the founding members of the Celestial Police. The monthly and for this time remarkably short-period publication of the MC allowed von Zach to circulate news from the world of astronomy faster among an interested ‘expert audience’. At the same time, it provided for a speedy exchange of observations and calculations as well as conjectures and hypotheses, which were of course advantageous for astronomical positioning. These features offer the (incredible) opportunity of reconstructing and analyzing scholarly debates and discussions at the time.

Title page of the “Monatliche Correspondenz” from 1803.

Unfortunately, the source corpus of 28 volumes of six issues each is strikingly under-researched. Except for a book by Dieter Herrmann on astronomical journals in Germany and a work by Peter Brosche on the life of Zach, there are no in-depth analyses of the history of this journal. Yet it is full of exciting topics, aside from the detailed exploration of the asteroids: In addition to travel reports by the young Alexander von Humboldt from South America, geographical surveys of the world, reports on solar eclipses and comet phenomena, treatises on the new metric system, it includes all kinds of studies on the sun, the moon and the stars that are yet to be explored.

The fact that the MC merges two genres of textual sources, letters as well as the nascent journal, makes it particularly exciting for historians of science. On the one hand, it offers the opportunity to reflect on the emergence of the “Fachzeitschrift” (scholarly or scientific journal) as a medium in the German-speaking world. On the other, historians can follow disciplinary developments in the history of astronomy and related sciences on a case-study basis. The Monatliche Correspondenz is thus a very special source. In subsequent blog posts, I will explore its characteristics as a digital source.


Aubin, David, Charlotte Bigg, and H. Otto Sibum, eds. The Heavens on Earth. Observatories and Astronomy in Nineteenth-Century Science and Culture. Durham/London: Duke University Press, 2010.

Brosche, Peter. Der Astronom der Herzogin. Leben und Werk von Franz Xaver von Zach, 1754–1832. Acta Historica Astronomiae 12. Frankfurt a.M.: Harri Deutsch, 2001.

Herrmann, Dieter B. Die Entstehung der Astronomischen Fachzeitschriften in Deutschland (1798-1821). Veröffentlichungen der Archenhold-Sternwarte Berlin-Treptow 5. Berlin-Treptow: Archenhold-Sternwarte, 1972.

Schroeter, Johann Hieronymus. Lilienthalische Beobachtungen der neu entdeckten Planeten Ceres, Pallas und Juno, zur genauen und richtigen Kenntniß ihrer wahren Grössen, Atmosphären und übrigen merkwürdigen Naturverhältnisse im Sonnengebiete. Göttingen: Vandenhoeck-Ruprechtische Buchhandlung, 1805, HathiTrust,

Zach, Franz Xaver von, ed. Monatliche Correspondenz zur Beförderung der Erd- und Himmelskunde. Gotha: Beckersche Buchhandlung, 1800-1813, Urmel/ThuLB,