Astrolabe by Ibrāhīm ibn Saʿīd as-Sahlī
Record status
Individual type · partial
Period
1068 (A.H. 460)
This brass astrolabe, designated inventory number 55331, was crafted by Ibrāhīm ibn Saʿīd as-Sahlī in Toledo in 1068 (A.H. 460). The instrument features a one-piece mater and limb construction with a nine-lobed, simple-type throne and an omega-shaped shackle.
The back of the device includes six distinct scales, covering degrees, zodiacal signs, a calendar, a solar cycle, and a shadow square. The rete displays influences of Moorish-arch design, with trefoil-shaped bases for its star pointers, including a bird-profile pointer for Aldebaran. The instrument is accompanied by six plates with latitudes ranging from 21° to 49° and a double-ended, counter-changed alidade. It was presented to the museum by Lewis Evans in 1924, having been acquired from a Milanese dealer in 1899.
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
- 1068 (A.H. 460)
- Type
- Arabic-inscribed astrolabe, Iberia
- Maker
- Ibrāhīm ibn Saʿīd as-Sahlī
- Material
- Brass
- Provenance
- Lewis Evans
- Throne style
- Nine lobes
- Place recorded
- Toledo
- Plate latitudes
- 21°0' to 49°0'
- Dealer provenance
- Cantoni
- Maker / attribution
- Ibrāhīm ibn Saʿīd as-Sahlī
Design
- Visible features
- • Nine-lobed throne design • Zoomorphic star pointer for Aldebaran • Double-ended counter-changed alidade • Six circular scales on the back plate
- Provenance and History
- This astrolabe was presented to the History of Science Museum, University of Oxford, in 1924 by collector Lewis Evans. Documentary records indicate that Evans originally purchased the piece in 1899 from a Milanese dealer named Cantoni. It is recognized within the collection as the earliest astrolabe manufactured in Europe. The instrument has undergone minor repairs, including the addition of four rotational knobs to the rete and the stabilization of one star pointer, which resulted in the loss of its original label.
- Construction and Design
- The astrolabe is constructed of brass and features a one-piece mater and limb. Unusually, the limb is formed by a thin metal plate cut to fit precisely between the mater ring and the throne. The throne itself is a simple type integrated with the base and characterized by a broad shape featuring nine lobes, to which an omega-shaped shackle is attached. The rete follows an indicator-line style showing Moorish-arch design influences. Most star pointers are set on bases resembling trefoils. The instrument includes six plates for varying latitudes and a double-ended, counter-changed alidade. One sighting vane on the alidade is currently reported as loose.
- Scales and Inscriptions
- The back of the astrolabe is densely engraved with six scales: degrees, zodiacal signs, a calendar, a solar cycle, and a shadow square. The zodiacal scale integrates the names of months in both Arabic transliteration and Latin. The instrument includes a specific maker's signature inscribed on the back, confirming the location and date of manufacture as Toledo in 1068. The womb contains inscriptions related to various locations including Qolzum, Madyan, and Kabul, alongside latitude and hour data. The meridian line on the front is engraved in Kufic script.
Identification
- Inventory number
- 55331
- 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 repair of the star pointer for the star labelled 'Al-Hawa' has obscured its original name
- Research required: One of the alidade sighting vanes is currently loose