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Leiden University archives, Observatory, directorate F. Kaiser

Identifier: ubl136

Scope and Contents

The archive includes both professional and personal correspondence, manuscripts and notes, course notes, and papers regarding the foundation of the new Leiden Observatory in 1861 and its new instruments.

Kaiser often kept drafts or transcripts of outgoing letters, so in many cases, both sides of a correspondence has been preserved. When this is not the case, the inventory indicates whether the preserved letters are to or from Kaiser.


  • Creation: 1820-1872
  • Creation: Bulk c. 1835-1872


Language of Materials

Mostly Dutch and German, some French and English.

Conditions Governing Use

Since the archive is digitized, the original papers are not free for public access, unless with permission of the curator after a written request with motivation. Other regulations that apply during the use of these materials can be found on the website of Leiden University Library.

Biographical / Historical

Frederik Kaiser (1808-1872) had no formal education; he learnt astronomy from his uncle. In 1835 he became known as an astronomer because of his correct calculations of the orbit of Halley’s comet. By that time, he had already been appointed as astronomer at Leiden University. In 1837 he became director of the Observatory of that university, and some years later he was also appointed professor.

At that time, the observatory was a rather rickety tower on top of the university building. Kaiser lobbied long and hard for funding for a new observatory. In 1861, he was finally able to open a new observatory.

Kaiser also worked as 'Verificateur van ‘s Rijks Zeeinstrumenten' (controller of Navy chronometers and compasses), and he participated in the Europäische Gradmessung . Besides, he was a prolific popular astronomy writer. His book De Sterrenhemel (2 vols, 1843-1845) became a bestseller.

Never having enjoyed a strong health, Kaiser died in 1872. His most important students were J.A.C. Oudemans and H.G. van de Sande Bakhuyzen, who succeeded him in Leiden.


242 items (c. 2,2 metre)

Abstract in Dutch

Archief afkomstig van Frederik Kaiser, hoogleraar sterrenkunde aan de Universiteit Leiden en directeur van de Leidse Sterrewacht (1837-1872). Dit archief bevat wetenschappelijke en persoonlijke correspondentie, manuscripten en aantekeningen, collegedictaten en papieren die betrekking hebben op de bouw van de nieuwe Leidse Sterrewacht in 1861 en de nieuwe instrumenten.

Abstract in English

Archive created by Frederik Kaiser, professor of astronomy at Leiden University and director of Leiden Observatory (1837-1872). This archive includes both professional and personal correspondence, manuscripts and notes, course notes, and papers regarding the foundation of the new Leiden Observatory in 1861 and its new instruments.


The inventory consists of the following categories:

Correspondence by correspondent (no. 1-115)
Correspondence by institution (no. 116-122)
Correspondence by subject (no. 123-127)
Personal correspondence and papers (no. 128-149)
Miscellaneous correspondence (no. 150-151)
Notes and manuscripts, including course notes (no. 152-182)
Notes and excerpts from literature (no. 183-192)
Observations, measurements and calculations (no. 193-201)
Observatory management (no. 202-216)
Instruments (no. 217-242)

To facilitate researchers, each file has been given a short title. In some cases these titles were original designations by the authors. The other titles are given by the author of this inventory. The main subject of each file is indicated in the inventory. This is not an exhaustive description, but a first indication, intended for researchers.

Correspondence has been ordered alphabetically by correspondent, following the Dutch system (disregarding prefixes such as van, van der etc).

Within the files, correspondence has been ordered chronologically. Other papers are preserved in the order in which they were found.

"Correspondence with ..." indicates that the file contains letters from both correspondents; "letters from …" indicates that only one side of the correspondence has been preserved in this archive.

Physical Location

Leiden University Library, Special Collections

Custodial History

This archive was created by Frederik Kaiser in the course of his work. The papers were preserved in Leiden Observatory until they were transferred to Leiden University Library in 2010.

Over the years, many people have consulted the archive, either for research or out of pure curiosity. Also, several papers have been temporarily removed for research purposes or for exhibitions. Most of these papers returned to the archive, with the exception of papers related to geodesy.

Some files come from the collections of the Boerhaave Museum and Leiden University Library. They have now been reunited with the Observatory Archives. These files are indicated in the inventory.

Immediate Source of Acquisition

The archive was transferred to Leiden University Library in 2010, by agreement between Leiden Observatory, Leiden University Library and the Department of Documentary Information and Archive Administration of Leiden University.


In several cases, only a selection of a file has been preserved. This exclusively concerns abstracts, references and other notes from astronomical literature. In these cases, a small part of the file has been preserved, while similar material has been deleted. These files have been indicated ('selection').

The selection was made by David Baneke, advised by Frans van Lunteren (Leiden Observatory) and Huib Zuidervaart (Huygens Institute).


No future additions are to be expected.

Existence and Location of Copies

The archive is digitized. The images are available in the inventory.

Related Materials

This archive is part of Leiden Observatory Archives, which contain the papers of the Observatory and its directors from c. 1830-1945.

The collection of Leiden University Library also includes the scientific papers of Jan Oort (director of the Observatory from 1945-1970).

Separated Materials

The manuscript collections of Leiden University Library also contain some correspondence of Kaiser with publishers. These can be found with the help of the digital catalogue.

Most of the papers related to Kaiser’s Navy work have been transferred to the Verificatiebureau in the 1880s. These papers are now kept in the Nederlands Instituut voor Militaire Historie (NIMH) in The Hague. The images can be seen on the website of Leiden University Library (AFA FC MEOB).

Papers related to the Gradmessung and the triangulation of the Dutch East Indies, which Kaiser supervised, were transferred to the Rijkscommissie voor Geodesie in Delft in the 1960s.

The images will be available on the website of Leiden University Library (AFA FC NCG).


  • Dekker, E., Frederik Kaiser en zijn pogingen tot hervorming van "het sterrenkundig deel van onze zeevaart", TGGNWT, 13 (1990) 23-41.
  • Dekker, E., Een procesverbaal van verhoor, Gewina , 15 (1992) 153-162.
  • Groeneveld, J.J., Kaiser, a Dutch family: snapshots by a camera obscura in the mirror of time. A family history about descendants of Johan Wilhelm Kaiser and Anna Sybylla Liernur and their relatives (Eemnes 2003).
  • Haasbroek, N.D., Prof. F. Kaiser en S. H. de Lange in hun relatie tot de astronomische plaatsbepalingen van omstreeks 1850 in het voormalige Ned. Indië (Delft 1977).
  • Herk, G. van, H. Kleibrink en W. Bijleveld, De Leidse sterrewacht. Vier eeuwen wacht bij dag en nacht (Zwolle 1983).
  • Hooijmaijers, H., De omzwervingen van een telescoop, Gewina, 26 (2003) 40-45.
  • Mohrmann, J.M., De KM als vernieuwer van de zeevaartkunde, 1850 - 1900, Tijdschrift voor Zeegeschiedenis, 22 (2003) 44-58.
  • Otterspeer, W., De wiekslag van hun geest. De Leidse universiteit in de negentiende eeuw (Den Haag 1992).
  • Zuidervaart, H.J. en R.H. van Gent, Between Rhetoric and Reality. Instrumental Practices at the Astronomical Observatory of the Amsterdam Society "Felix Meritis", 1786-1889 (forthcoming).
  • Zuidervaart, H.J., Frederik Kaiser [papers presented at the celebration of Kaiser’s 200th birthday, 2008 (forthcoming).

Processing Information

The papers have been reordered and repacked. The original files were maintained as much as possible. Most of the folders were created by Kaiser himself or by his successor H.G. van de Sande Bakhuyzen. Obviously misfiled papers have been refiled, and obviously related papers have been put together, while obviously unrelated papers have been separated.

Collection guide of the Leiden University archives, Observatory, directorate F. Kaiser (1820-1872)
Archieven van de Universiteit Leiden - Sterrenwacht, directoraat F. Kaiser
David Baneke, 2010
Language of description
Script of description
Code for undetermined script
Language of description note
Beschrijving is in het Engels.

Revision Statements

  • 10 September 2015: latest update

Repository Details

Part of the Leiden University Libraries Archives & Collections Repository

Witte Singel 27
Leiden 2311 BG Netherlands
+31 71 527 2857