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The Encyclopedia of Horology

Tool · Arabic-inscribed astrolabe

Brass Astrolabe by Khalīl Muḥammad ibn Ḥasan

Partially verified

This brass astrolabe (inventory 46680) is attributed to the maker Khalīl Muḥammad ibn Ḥasan, dated to 1708/9, and originating from Iṣfahān. The instrument features an Indo-Persian style engraved throne, a simple circular ring, and an omega-type shackle. The mater and limb are constructed as one piece. It is equipped with five plates covering latitudes from 22° to 43° and a foliate-type rete featuring 22 stars marked with bulb pointers. The back contains a comprehensive set of 14 astronomical and astrological scales, including altitude, azimuth of Qibla, zodiacal signs, and lunar mansions. The assembly includes a double-ended alidade, and the entire unit is secured with an ornate horse and pin.

Front view of the brass astrolabe (inventory 46680) showing the rete, throne, and suspended ring with silk tassel.
Front view of the brass astrolabe (inventory 46680) showing the rete, throne, and suspended ring with silk tassel. — History of Science Museum, University of Oxford. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
www.mhs.ox.ac.uk
Category
Tool · Arabic-inscribed astrolabe
Maker / attribution
Khalīl Muḥammad ibn Ḥasan
Reference
46680
Catalogue / lot identifier
1957-84/9
Source-reported date
1708/9
Source-reported place
Iṣfahān

Source-reported attribution and specifications are not independent authentication. A listing does not establish present ownership, current display, availability or permission to reproduce.

Object description

Construction and Design

The astrolabe is constructed from brass, featuring an integrated mater and limb. The throne is categorized as an Indo-Persian engraved type with a Moorish-arch shape, embossed with a floral pattern and inscription. It is attached to a simple, round-section ring and an omega-shaped shackle, the latter of which features an engraved texture on its outer edge.

The rete is of the foliate type with a single knob, attached to the instrument with a simple, thick pin and an ornate horse. The rete contains 22 stars, each identified by a bulb pointer. Five plates are provided for the instrument, accommodating latitudes ranging from 22°0' to 43°0'.

Evidence for this section
  • “The throne is of the indo-persian, engraved type made of brass”
  • “The rete is of the foliate (single knob) type.”
  • “There are 5 plates with latitudes ranging from 22°0' to 43°0'”

Astronomical and Astrological Features

The back of the instrument hosts 14 distinct scales, including altitude, azimuth of the Qibla, declination, a shadow square, and various astrological divisions such as lunar mansions, triplicities, and zodiacal signs. A gazetteer on the womb provides coordinate data for 44 cities, including Mecca, Iṣfahan, and Lahore.

The alidade is double-ended, rigid, and original to the piece, featuring pinholes and scales for sine/cosine measurements and unequal hours.

Evidence for this section
  • “The back contains 14 scales”
  • “The womb contains a gazetteer with coordinates for 44 cities”
  • “Alidade Double-ended.”

Signatures and Provenance

The instrument bears a signature on the back which translates to 'Muhammad Khalil made this'. The astrolabe has a documented provenance through the collection of Henri Michel of Brussels, which was acquired by J. A. Billmeir around 1950.

The object was presented to the History of Science Museum by J. A. Billmeir in 1957 and assigned the accession number 1957-84/9.

Evidence for this section
  • “The back is inscribed: with a maker's signature marked as محد خليل صنعه (Muhammad Khalil made this).”
  • “Billmeir acquired it with the collection of Henri Michel, of Brussels, which he purchased about 1950.”

Open research questions

  • What was the intended primary usage environment given the specific latitude range of the plates?
  • Does the engraving style on the throne align with other known works by the same maker in institutional collections?

Source evidence

Recorded claims and source quotations for Brass Astrolabe by Khalīl Muḥammad ibn Ḥasan
FieldSource-reported valueSource quotation
Inventory number46680“Inventory no. 46680”
MakerKhalīl Muḥammad ibn Ḥasan“Maker Khalīl Muḥammad ibn Ḥasan ‘Alī”
Date1708/9“Date 1708/9”
PlaceIṣfahān“Place Iṣfahān”
MaterialBrass“Material Brass”
Acquisition1957“Presented by J. A. Billmeir in 1957”
Rete stars22“There are 22 stars on the rete”
Plates5“There are 5 plates”

Visible details

  • Indo-Persian engraved throne with floral pattern and inscription
  • Rete featuring 22 stars with bulb pointers
  • Back of the instrument includes a shadow square and 14 different scales
  • Double-ended alidade and original pin with ornate horse

Research qualifications

  • The provenance is stated to be through Henri Michel, but exact early history remains undocumented
  • Construction marks on the back of the rete indicate potential technical adjustments during manufacture

Photograph identity and source facts were screened before import; rights clearance remains pending.

Consulted source

Astrolabe, inventory 46680 (Iṣfahān, 1708/9)

Reviewed 2026-10-26 · Record 440cfa681d

Terms in this record

Glossary explanations for terms named in this object’s record.

Other arabic-inscribed astrolabe records