Astrolabe by Blakene
Record status
Individual type · partial
Period
1342
This planispheric astrolabe, crafted from brass and measuring 218 mm in diameter, is signed by its maker, Blakene, and dated 1342. Recognized as the earliest signed and dated European instrument of its type, it features a tri-lobed throne, a long shackle, and a decorated ring.
The rete includes a quatrefoil base for star pointers, which is inscribed with the maker's name and date. The central disc is hollowed out into four quadrants with cross-shaped supports. The instrument includes two plates marked for latitude 52 degrees north and other astronomical functions, alongside an alidade with sighting vanes and a ruler. The reverse side features altitude scales, a solar scale, and complex concentric calendrical scales.
The instrument was donated to the British Museum in 1853 by Joseph Mayer and is documented in scholarly catalogs regarding historical scientific instruments.
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
- 1342
- Type
- English astrolabe
- Maker
- Blakene
- Diameter
- 218 mm
- Star count
- 38
- Place recorded
- England
- Maker inscription
- Blakene me fecit anno domini 1342
- Maker / attribution
- Blakene
Design
- Visible features
- • Tri-lobed throne construction with decorated shackle • Dragon head-shaped terminations on the tropic of Capricorn • Engraved inscriptions for thirty-eight individual stars • Concentric calendrical scales on the instrument reverse
- Construction and Design
- The astrolabe is a brass circular instrument measuring 218 mm in diameter. It possesses a tri-lobed throne integrated with a decorated long shackle and a suspension ring. The mater, the main body of the instrument, features a double-line decoration around its perimeter and is graduated in degrees clockwise. The internal central disc structure is hollowed into four quadrants, supported by a cross-shaped element connecting the inner and outer rings. The rete is characterized by a central quatrefoil that supports various star pointers and bears the maker's signature and the year of manufacture. The equatorial bar is connected to the tropic of Capricorn via three stylized columns, and each end of the tropic of Capricorn is shaped to resemble a dragon's head. The ecliptic is marked with zodiac signs and graduated for astronomical calculation.
- Signature and Documentation
- The instrument is significant for being the earliest known signed and dated European scientific instrument. The maker is identified only by the name Blakene, as no further biographical information is available. The signature and date are clearly inscribed on the top lobe of the quatrefoil located on the rete. The item's provenance is tied to its 1853 donation by Joseph Mayer. It has been examined in multiple historical studies of scientific instruments, including works by R. T. Gunther and F. A. B. Ward, which detail its technical specifications and physical composition as held in the British Museum collection.
- Plates and Astronomical Functions
- The instrument includes two plates providing specific astronomical data. The first plate is configured for a latitude of approximately 52 degrees North, featuring circles for the tropics, the equator, azimuths, and lines representing unequal hours. The second plate provides circles for the tropics and the equator but is otherwise blank on one side, with lines for the houses in the manner of Regiomontanus on the other. The reverse side of the instrument provides a comprehensive set of scales for solar and calendrical tracking. It incorporates four altitude scales, a solar scale inscribed with zodiac names, and multiple concentric bands for tracking solar cycles, day letters, and dominical letters. A pair of shadow scales is located in the lower half of the reverse.
Identification
- Reference
- MLA 1853,11-4.1
- Accession number
- MLA 1853,11-4.1
- 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: Purpose of the small numerals '3, 6, 8, 9, 8' on the edge remains uncertain
- Research required: Originality of the wedge, which is noted as a replacement