Skip to content
The Encyclopedia of Horology

Tool · German astronomical compendium

Astronomical Compendium by Tobias Volckmer

Partially verified

This astronomical compendium, signed by Tobias Volckmer and dated 1588, is a portable scientific instrument constructed from gilt brass and silver. Measuring 74 x 74 x 27 mm, it features a complex arrangement of components including a horizontal dial with a triangular gnomon, a central compass, and a thread reel with four colored threads and an adjustable protractor. The interior and exterior surfaces are densely engraved with various scales, including degree scales, zodiacal signs, and calendrical data, as well as decorative fruit and strapwork motifs. It provides multiple functions for timekeeping and astronomical calculations, accommodating different latitudes and including lists of cities and their respective elevations. The device is housed in the British Museum.

Astronomical compendium by Tobias Volckmer, 1588, showing the main box and the detached thread reel component.
Astronomical compendium by Tobias Volckmer, 1588, showing the main box and the detached thread reel component. — British Museum, London. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
www.mhs.ox.ac.uk
Category
Tool · German astronomical compendium
Maker / attribution
Tobias Volckmer
Reference
MLA 1886, 4-19.1
Catalogue / lot identifier
MLA 1886, 4-19.1
Source-reported date
1588
Source-reported place
Germany

Source-reported attribution and specifications are not independent authentication. A listing does not establish present ownership, current display, availability or permission to reproduce.

Object description

Construction and Exterior

The instrument is a gilt brass and silver box measuring 74 x 74 x 27 mm. Its exterior features extensive engravings, including a circular scale of degrees and shadow squares labeled 'VMBRA RECTA' and 'VMBRA VERSA'. The sides of the main box are decorated with strapwork and fruit motifs.

Specific linear scales are present on three sides, numbered 1 to 8 and 1 to 4 with fractional subdivisions. Two metal catches are positioned on the sides to secure the instrument in an open position during use.

Evidence for this section
  • “Gilt brass and silver; 74 x 74 x 27 mm”
  • “The outside of the covering leaf is engraved with a circular scale of degrees”
  • “The sides of the main box are engraved with fruit and strapwork decoration”

Dials and Astronomical Components

The interior contains a horizontal dial with a silver and brass triangular gnomon adjustable for three latitudes. A rotating compass plate is situated within the base, marked with German direction names and surrounded by silver scales for time and degrees.

A thread reel component is stored within, featuring four colored threads and a sliding protractor marked 'HORIZONT RECTVS'. The reverse of the rotating silver plate and the lower brass base contain engravings of multiple cities and their corresponding latitudes.

Evidence for this section
  • “Inside the shadow square is the signature 'THOBIAS VOLCHKMER BRAVNSWEIGSENSIS FACIEBAT ANNO CHX 1588'”
  • “The inside of the lid has a horizontal dial with triangular solid gnomon”
  • “Inside the case is a silver thread reel, with four threads of different colour (red, white, green and blue) wound on it”

Provenance and Documentation

The instrument is held by the British Museum under the registration number MLA 1886, 4-19.1. It was acquired by the museum in 1886.

The object is referenced in F. A. B. Ward's catalogue of scientific instruments. The auction house/museum records note that a new compass glass was fitted to the instrument in 1934.

Evidence for this section
  • “The instrument was purchased in 1886”
  • “A new compass glass was fitted in 1934”
  • “described in F. A. B. Ward, A Catalogue of European Scientific Instruments in the Department of Medieval and Later Antiquities of the British Museum (London, 1981), p. 123, no.355”

Open research questions

  • What specific purpose did the four-colored threads serve in the astronomical calculations of this instrument?
  • How does the listed city latitude data compare to modern geographical measurements?

Source evidence

Recorded claims and source quotations for Astronomical Compendium by Tobias Volckmer
FieldSource-reported valueSource quotation
MakerTobias Volckmer“Signed by Tobias Volckmer”
Date1588“Dated 1588”
LocationBrunswick“Brunswick”
Dimensions74 x 74 x 27 mm“74 x 74 x 27 mm”
MaterialGilt brass and silver“Gilt brass and silver”
Registration NumberMLA 1886, 4-19.1“Registration no. MLA 1886, 4-19.1”
RepositoryBritish Museum, London“British Museum, London”

Visible details

  • Instrument case features strapwork and fruit engravings on the exterior sides
  • Compass plate contains names of cardinal directions in German
  • Central thread reel features red, white, green, and blue threads

Research qualifications

  • Compass glass was reported replaced in 1934
  • Attribution to Tobias Volckmer based on the signed signature 'THOBIAS VOLCHKMER BRAVNSWEIGSENSIS'

Photograph identity and source facts were screened before import; rights clearance remains pending.

Consulted source

Astronomical Compendium

Reviewed 2026-10-26 · Record e9662fe420

Terms in this record

Glossary explanations for terms named in this object’s record.

Other german astronomical compendium records