Nocturnal and Sundial, 1578
Record status
Individual type · partial
Period
1578
This unsigned gilt copper nocturnal and sundial, dating to 1578 and manufactured in Rome, measures 83 mm in diameter. The instrument features a base plate with a shaped, pierced handle and a suspension ring.
The sundial face contains a base plate with a raised edge for latitude adjustment and a reversible circular plate featuring a Rojas projection for an altitude sundial. This projection includes a pierced and decorated trigonus with sights and a plumb-rule. The reverse of the disc comprises a double shadow square and a degree scale for altitude measurement, accompanied by foliate decoration. The nocturnal face displays a zodiacal calendar with constellation names and symbols alongside a month scale.
An index arm, scrollwork, and foliate decoration adorn the center of the hour disc. The entire assembly is joined by a threaded tube and a wing nut, allowing the instrument to be disassembled for specific functional uses.
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
- 1578
- Type
- Italian nocturnal and sundial
- Diameter
- 83 mm
- Material
- Gilt copper
- Place recorded
- Rome
- Inscriptions on disc
- ROM?. ao. 1578
Design
- Visible features
- • Instrument is constructed of gilt copper • Base plate includes a shaped, pierced handle • Hour disc features scrollwork and foliate ornamentation • Assembly utilizes a threaded tube and wing nut
- Attribution and Design
- The instrument is unsigned and is associated with a 1578 origin in Rome. The use of gilt copper in this specific configuration is noted as unusual for the period, with the Museum of the History of Science linking the technique to the output of Erasmus Habermel. The design emphasizes ingenuity, specifically regarding the reversible plate which features a raised rim. The scales located on the reverse of the plate are intended for use with the trigonus sights, allowing the object to function as a versatile mathematical tool.
- Reverse Face and Nocturnal Features
- The reverse side of the reversible disc features a double shadow square, which is divided and subdivided for shadow calculations, labeled as 'Umb: Recta', 'Umbra Versa', and 'Vm: Recta'. The upper portion of this side contains an additional degree scale for measuring solar and stellar altitudes, inscribed with the production location and date. The nocturnal component features a zodiacal calendar with constellation names and symbols, each accompanied by a 30-degree scale. A month scale is also provided, divided into 10-day and 1-day intervals. The hour disc uses Roman numerals to indicate time, and the central area is decorated with scrollwork and foliate patterns.
- Sundial Construction and Components
- The sundial face incorporates a base plate with a raised edge for latitude adjustment, calibrated from 90 to 0 to 90 degrees. Within this perimeter sits a reversible circular plate designed with a Rojas projection, specifically for the organum Ptolemai form of altitude sundial. The projection features meridian and polar markers alongside zodiacal scales labeled 'Austratia Signa' and 'Borealia Signa'. The instrument is further equipped with a pierced and decorated 'trigonis' that includes integral sights and a plumb-rule. This component is essential for the instrument's disassembly and re-assembly process. The entire assembly is held together using a central threaded tube and a wing nut, which secures the trigonus to the base plate.
Identification
- Inventory number
- 48140
- 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: Maker is unsigned, though construction relates to the work of Erasmus Habermel
- Research required: Exact functional interaction between scales and trigonus remains a theoretical utility