English Planispheric Astrolabe
Record status
Individual type · partial
Period
1350-1450, 1400-1600 (second half of 14th century proposed by Davis)
The National Museum of American History preserves this brass planispheric astrolabe, documented under catalog number MA.318198 and referred to in literature as CCA No.
2006. Source notes indicate it was manufactured in England, with dating estimated across 1350–1450 and 1400–1600, while John Davis proposes the second half of the fourteenth century. The instrument features an openwork rete showing northern sky stars with zoomorphic pointers shaped as animal tongues. Concentric brass circles define the Tropic of Capricorn and an eccentric zodiac ring. Beneath the rete, the plate scales are inscribed directly for 52 degrees latitude without separate interchangeable plates.
Source notes report a later sundial scale on the reverse and a front-mounted sighting device used to calculate celestial positions and time of night.
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
- Type
- Scientific instrument
- Material
- Brass
- Latitude Scale
- 52 degrees
- Place recorded
- England
- Rete Design Style
- Zoomorphic
- Overall Dimensions
- 17.9 cm x 12.9 cm x 1.1 cm
- Museum Catalog Number
- MA.318198
- Country of Manufacture
- England
Design
- Visible features
- • Circular brass suspension ring attached via a small decorative bracket at the top rim. • Openwork rete with zoomorphic star pointers depicted as animal heads and protruding tongues. • Eccentric circular zodiac ring crossed by a pivoted straight brass sighting rule across the face. • Multi-ringed concentric degree and astronomical scales inscribed on the brass rim and plate.
- Operational Features
- The astrolabe includes a front-mounted sighting device and a pivoted rule used to measure stellar height, which allowed users to calculate the time of night and stellar positions. The reverse of the object features a sundial scale. This scale is identified in the source as a later addition to the original instrument.
- Construction and Design
- The instrument is a brass planispheric astrolabe of English origin. It lacks interchangeable plates, instead featuring scales inscribed directly for 52 degrees latitude. The front includes an openwork rete acting as a star map of the northern sky. It is described as a 'zoomorphic' instrument, with star pointers shaped like animal tongues. The face also features the Tropic of Capricorn and an eccentric zodiac ring.
- Chronological Documentation
- The manufacturing date of the astrolabe is recorded with varying estimates in museum metadata, ranging from 1350–1450 and 1400–1600. The source notes the instrument may have been made before 1500. Scholarly research by John Davis specifically dates the instrument to the second half of the fourteenth century.
Identification
- Reference
- CCA No. 2006
- 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: The reverse face containing the later sundial scale mentioned in the source is not shown in this photograph.
- Research required: Dates of manufacture range in source documentation from 1350–1450, 1400–1600, and the second half of the fourteenth century.