Planispheric Astrolabe
Record status
Individual type · partial
Period
14th century ?
This planispheric astrolabe, crafted from brass and measuring 114 mm in diameter, is unsigned and undated. However, the instrument is engraved with Gothic letters and numerals, leading to an attribution of 14th-century Spanish origin.
The instrument comprises a mater with a 360-degree altitude scale, multiple plates for varying latitudes, a rete with zodiacal markings, and an alidade. Construction markings appear on the reverse of the rete. The back features Julian calendar scales and zodiacal divisions. The piece includes later additions, specifically a poorly engraved double shadow square and a superimposed horary quadrant. The pin head is flower-shaped, and the wedge is shaped like a stylized horse.
It was acquired from the Findlay collection and is held by the British Museum.
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
- 14th century ?
- Type
- Iberian astrolabe
- Origin
- Spanish
- Diameter
- 114 mm
- Material
- Brass
- Place recorded
- Spain
- Later additions
- Double shadow square and horary quadrant
Design
- Visible features
- • The throne has three lobes on each side • The rete features unmarked star pointers in flame shapes • The instrument displays Gothic script • The wedge is designed as a stylized horse
- Plates and Calendar Scales
- The instrument includes three internal plates and one plate integrated within the mater, all marked with tropical and equatorial circles. These plates provide almucantars at 6-degree intervals and lines for unequal hours. They are marked for seven different latitudes, known as the seven climates, ranging from 15 to 48 degrees. The mater itself is marked for latitude 15 degrees. The back of the instrument features circular scales for the zodiacal signs and the Julian calendar. The zodiacal signs are divided into 30-degree segments, subdivided into single degrees. The calendar scale lists the months with Latin names, divided into the appropriate number of days. These scales indicate that the equinoxes fall on March 15 and September 17.5.
- Condition and Later Modifications
- The instrument is largely considered unfinished, as evidenced by the lack of labels on the star pointers. Further analysis of the back of the instrument indicates that the lower portion of the vacant space contains a double shadow square and a superimposed horary quadrant. These elements are described as being poorly engraved and are interpreted as later additions to the original structure. This instrument is part of the British Museum collection, having been purchased from the Findlay collection via Sotheby's in 1961. It is documented in F. A. B. Ward's catalogue of European scientific instruments, confirming its historical and academic placement within the Department of Medieval and Later Antiquities.
- Structural Design and Construction
- The astrolabe is constructed of brass and measures 114 mm in diameter. Its rim, soldered to the backplate, features an altitude scale of 360 degrees, divided into single degrees and numbered by fives. The throne, which follows a design seen on early Islamic instruments, is triangular with three lobes on each side, and the shackle is suspended from two interlocked rings. The rete maintains this Islamic-inspired aesthetic, featuring unmarked flame-shaped star pointers set on quadruple lobes. The ecliptic is marked with Latin names for the zodiacal signs, which are partially abbreviated, with each sign divided into 6-degree segments. Construction markings are visible on the reverse side of the rete. The pin head is shaped like a flower, and the wedge is stylized in the form of a horse, providing a distinct decorative contrast to the functional components of the instrument.
Identification
- Inventory Number
- MLA 1961,12-1.1
- 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: The exact date of manufacture is uncertain and queried as the 14th century in documentation
- Research required: The attribution to Spanish origin is suggested by the combination of Islamic-style design and Gothic engraving