Astronomical Compendium, circa 1600
Record status
Individual type · partial
Period
circa 1600
This astronomical compendium, held in the collection of the Museum of the History of Science, Oxford, is an unsigned brass instrument dating from circa 1600 and attributed to French manufacture.
The object measures 87 x 87 x 39 mm and features a square box structure with a hinged cover lid. Its functional components comprise a nocturnal, an equinoctial sundial, and a compass. The instrument is distinguished by its deep compass bowl and elaborate exterior decoration, which includes foliate patterns and engraved roundels featuring portrait heads of two women and two helmeted men. The nocturnal is situated on the cover, while the equinoctial dial occupies a recess above the compass.
The instrument is secured with a horse's head-shaped clasp. The brass construction and specific mechanical arrangements for the sundial gnomon and volvelle are consistent with the technical requirements for portable timekeeping and astronomical observation during the early seventeenth century.
Evidence at a glance
- Linked sources
- 1
- Photograph views
- 1
- Catalogue references
- 0
Counts describe this entry’s documentation, not authenticity, rarity or completeness. Photographs may show one specimen; check each caption and licence.
Technical characteristics
- Date
- circa 1600
- Type
- French astronomical compendium
- Dimensions
- 87 x 87 x 39 mm
- Place recorded
- France
- Attributed Origin
- French
- Compass Variation
- 18 degrees West
Design
- Visible features
- • Case sides feature foliate motifs surrounding circular portraits of human figures • Magnetic compass includes a blued south-pointing needle • Equinoctial dial gnomon is adjustable across three latitude positions • Nocturnal features a toothed volvelle for star-time calculation
- Astronomical Functions
- The instrument functions as a nocturnal and an equinoctial sundial. The nocturnal is situated on the outward face of the cover, utilizing a decorated, hinged index and a toothed volvelle. The volvelle features radiating lines for hours IIII to XII to VIII, subdivided to half-hour increments. A calendar scale is provided, where months are identified by their initial letters and subdivided to five days. The nocturnal is calibrated for a star with a right ascension corresponding to the sun's position on approximately 13 October. The equinoctial dial is located in a recess above the compass. The gnomon is a cross-piece design, which can be placed into one of three unnumbered indentations on a brass bar, allowing for three distinct latitudes. This mounting prevents the gnomon from being strictly perpendicular to the hour ring. The hour ring itself is circular with a scroll-shaped, ungraduated night-time portion.
- Compass and Decoration
- The large compass is integrated into the base of the instrument. Instead of a conventional degree scale, it features a circular scale divided to 5 and 1, numbered by 5 in a 30-0-30-0-30 pattern. The needle is blued and south-pointing. The four cardinal points are marked with crossed lines, and a star symbol denotes North. An indicator on the base plate marks a magnetic variation of about 18 degrees West. Beyond the primary astronomical markings, the instrument displays deliberate ornamental choices. The base of the instrument carries a simple circular geometric design. The maker also integrated the portrait heads into the side panels, which are interpreted as generalized depictions rather than specific historical figures.
- Structural Design and Exterior
- The compendium is constructed as a square brass box measuring 87 mm by 87 mm with a height of 39 mm. It features a hinged lid, which is secured closed by a clasp shaped in the form of a horse's head and neck. A hinged piece with a trefoil aperture is mounted on the cover, designed to function as a handle or suspension point. The exterior vertical surfaces are decorated with engraved foliate patterns, arranged around four roundels. Within these roundels are engravings of portrait heads, comprising two women and two helmeted men. These decorative elements occupy the sides of the box, with the cover itself remaining blank on the underside. The overall build includes a deep compass bowl, contributing to the instrument's significant dimensions relative to the specific set of functions provided.
Identification
- Inventory Number
- 50593
- Source note
- Facts transcribed from the linked source listing or collection record. Attribution and specifications are source-reported and have not been independently authenticated.
Catalogue references
No catalogue numbers recorded. Numbers are only published once transcribed from a verified edition of a standard catalogue — they are never inferred.
Research required
- Research required: Portrait heads are described as likely generalized rather than specific depictions
- Research required: Magnetic variation measurement of 18 degrees West is of uncertain historical origin