Brass Astrolabe, 18th century
Record status
Individual type · partial
Period
18th century
This 18th-century brass astrolabe is catalogued as inventory number 50180 in the History of Science Museum, University of Oxford. The instrument features a one-piece mater and limb construction, with a small internal tab at the bottom to prevent tympan rotation.
It is fitted with an Indo-Persian style broad throne, an eye-bolt shackle, and a simple round cross-section ring. The rete is of the foliate type, featuring sixteen star pointers. Six plates are included, covering latitudes from 22° to 66°. The back of the instrument contains seven scales, including altitude, declination, sine/cosine, shadow squares, and cotangent scales. The instrument is secured with a plain pin and a crude horse-shaped wedge.
It was acquired by the museum in 1957 as a gift from J. A. Billmeir, having previously been part of the Charles Chadenat collection sold in Paris in 1956.
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
- 18th century
- Type
- Arabic-inscribed astrolabe
- Material
- Brass
- Provenance
- Presented by J. A. Billmeir in 1957
- Place recorded
- Persia (?)
- Place of origin
- Persia (?)
- Number of plates
- 6
- Number of star pointers
- 16
Design
- Rete and Alidade
- The rete, of the foliate type, displays sixteen stars marked with foliate pointers. The zodiac labels are etched onto the ecliptic ring. Various construction marks, such as circles for the equator and tropics, are visible on the reverse side of the rete. The rete is fixed to the mater using a plain pin and a crude, horse-shaped wedge. The alidade is double-ended and rigid, featuring single sights and pinholes. It is entirely plain and contains no decorative engravings or additional markings.
- Visible features
- • The throne culminates in a tulip-shaped point where the shackle attaches. • The rete contains 16 star pointers identified by foliate shapes. • The instrument includes a double-ended alidade which is plain and lacks decorative engravings. • The suspension ring is formed from an oval-shaped rod bent into a circle, with ends remaining unsoldered.
- Back Scales and Provenance
- The back of the instrument is engraved with seven distinct scales. These include concentric altitude scales for the upper quadrants, declination and sine/cosine arcs, and two types of shadow square boxes. Circular cotangent scales are also present in the lower quadrants of the outer edge. The provenance records indicate that J. A. Billmeir purchased the astrolabe at the auction of the Chadenat collection, held at the Hôtel Drouot in Paris on May 24, 1956. The object was later presented to the History of Science Museum in 1957.
- Construction and Main Body
- The astrolabe is constructed primarily of brass and features a one-piece mater and limb. The limb includes a degree scale numbered every 5 degrees, spanning 0 to 360 degrees. To ensure the correct orientation of the tympans, a small tab is situated at the bottom of the limb on the interior. The womb contains a gazetteer with coordinates for 22 specific cities. The throne follows the Indo-Persian broad style and includes an integrated support and base. A tulip-shaped point serves as the attachment point for the shackle. The shackle consists of two parts: an eye-hole at the top for the suspension ring and a box-shaped section that fixes to the throne.
Identification
- Inventory number
- 50180
- 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 attribution to Persia is designated as tentative by the source.
- Research required: The precise maker of the instrument is currently unknown.