North African Astrolabe, late 18th century
Record status
Individual type · partial
Period
late 18th century
This planispheric astrolabe, catalogued under inventory number 40407, is a brass scientific instrument attributed to North Africa and dating to the late 18th century.
The instrument features a simple-type brass throne with an integrated base, a simple round-section ring, and an eye-bolt shackle. The mater and limb consist of two riveted pieces, with a notch for the tab positioned at the throne. The womb contains engravings suggesting an intended gazetteer, though this was never completed. The instrument includes two latitude plates ranging from 21°0' to 36°0'. The back is engraved with six distinct scales, including altitude, zodiacal signs, calendar, unequal hours, and a shadow square.
The instrument was acquired by the History of Science Museum, University of Oxford, in 1957 as a gift from J. A. Billmeir, who had previously purchased the item from the collection of Henri Michel in Brussels around 1950.
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
- late 18th century
- Type
- Arabic-inscribed astrolabe, North Africa
- Place
- North Africa
- Shackle
- Eye-bolt type
- Material
- Brass
- Acquisition
- Presented by J. A. Billmeir in 1957
- Throne style
- Simple type
- Place recorded
- North Africa
Design
- Provenance
- The astrolabe was incorporated into the History of Science Museum, University of Oxford, collection in 1957, following its presentation by J. A. Billmeir. The item carries the accession number 1957-84/14. Prior to its acquisition by Billmeir, the astrolabe was part of the collection held by Henri Michel of Brussels. Records indicate that Billmeir purchased the Michel collection around 1950.
- Visible features
- • Throne constructed in two pieces with the back as an extension of the back plate • Womb displays evidence of an incomplete gazetteer engraving • Limb features a circular degree scale numbered every 5 degrees
- Scales and Plates
- The back of the instrument provides a comprehensive set of six scales for astronomical and timekeeping calculations. These include two altitude scales covering 0 to 90 degrees in the upper quadrants, a circular zodiacal scale, and a calendar scale spanning the full circle. Unequal hours are represented in the upper left quadrant. Additionally, a shadow square is present in the lower quadrants, with scales marked for feet in 1-unit increments. The instrument includes two interchangeable plates, providing latitudes that range between 21°0' and 36°0'.
- Construction and Mater
- The astrolabe is fabricated from brass and incorporates a two-piece, riveted mater and limb construction. The assembly includes a simple-type throne featuring an integrated base. This throne is designed in two sections: the back portion serves as an extension of the back plate, while the front is integrated into the limb. The instrument is suspended by a simple, round cross-section ring secured via an eye-bolt type shackle, which attaches to an angle bracket. The womb of the mater bears engravings that indicate the maker intended to include a gazetteer, although the work remains unfinished. A tab notch is located at the position of the throne to ensure proper alignment. The limb is graduated with a circular, concentric degree scale ranging from 0 to 360 degrees, with numbering occurring at 5-degree intervals.
Identification
- Accession number
- 1957-84/14
- Inventory number
- 40407
- 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 origin within North Africa is not specified
- Research required: The specific latitudes for the two plates are limited to a range of 21°0' to 36°0'