Gilt Copper Astrolabe
Record status
Individual type · partial
Period
Later 16th century
This unsigned astrolabe, dating to the later 16th century, is constructed from gilt copper and measures 85 mm in diameter. The instrument features a throne composed of a double block, with an integrated attachment for a ring.
It includes two internal plates calibrated for latitudes of 37° and 40°, corresponding to Spanish locations, which supports the attribution of its origin. The mater remains unmarked. The back of the instrument is distinctive for its use of the orthographic projection developed by the Spanish mathematician Juan de Rojas, which occupies approximately three quarters of the surface area. The astrolabe is completed by a hinged bar graduated in 15° intervals.
The limb of the instrument is graduated in four 90° quadrants. Its design incorporates various astronomical markings, including zodiacal symbols, meridians, and parallels, as well as specific Latin inscriptions related to astronomical observation and the Rojas projection system.
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
- Iberian astrolabe
- Materials
- Gilt copper
- Dimensions
- 85 mm diameter
- Place recorded
- Spain
- Latitude plates
- 37 and 40 degrees
- Limb graduation
- 90 to 0 degrees, repeated twice
- Projection System
- Orthographic projection of Juan de Rojas
Design
- Visible features
- • Throne features a double block construction. • Limb is graduated from 0 to 90 degrees in four segments. • Hinged sighting bar is graduated. • Rojas projection is visible on the rear surface.
- The Rojas Projection and Back Plate
- A central element of this astrolabe is the use of the orthographic projection established by the Spanish mathematician Juan de Rojas. This projection covers approximately three quarters of the rear surface of the device. The design includes meridians beginning from a cap inscribed 'ARTICVS' and includes specific labeling regarding the time, marked 'HORAE ANTE MERIDIEM'. The entire assembly is complemented by a hinged bar at the rear, featuring graduations between 15° and 90°.
- Structural Components and Dimensions
- The astrolabe is a compact instrument measuring 85 mm in diameter, manufactured from gilt copper. Its suspension system is anchored by a throne formed from a double block, which provides the anchor point for the ring. The design reflects an integration of both functional astronomical utility and specific geometric projection. The instrument includes a mater, which is noted as lacking specific markings, alongside two separate plates calibrated specifically for the latitudes of 37° and 40°. This calibration suggests alignment with Spanish geographical locations, reinforcing the attribution of the object's origin.
- Limb Graduations and Chronological Context
- The limb of the instrument is calibrated in four quadrants, each graduated from 0° to 90°. The exterior side of the device features additional astronomical data, including the initials of the months and symbols representing the zodiac signs along with the corresponding day of entry. The instrument remains unsigned and undated, leading researchers to rely on the projection technique and the geographical calibration of the plates to determine its context. These factors point to a production date in the latter half of the 16th century within Spain.
Identification
- Inventory Number
- 1108
- 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: Origin is attributed based on geographical indicators rather than a maker's signature.
- Research required: The dating to the later 16th century is an estimation provided by the institution.