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The Encyclopedia of Horology

Tool · Scientific instrument

Brass Astrolabe AST0580

Partially verified

Catalogued under object identification AST0580 at the National Maritime Museum, Greenwich, this brass astrolabe is dated to 1813 (AH 1228). The instrument measures 60 mm in diameter and 93 mm in total length including its throne. The throne is tri-lobed and engraved with a Koranic verse. According to museum documentation, the mater holds a 24-locality gazetteer and seven plates engraved for latitudes between 21° and 40°, three lacking labels. The reverse features a sine quadrant and double shadow square. A Persian rim inscription referencing Jamshid provides a chronogram yielding the AH 1228 date.

Front view of brass astrolabe AST0580 showing the throne, rim markings, and rete
Front view of brass astrolabe AST0580 showing the throne, rim markings, and rete — National Maritime Museum, Greenwich, London, Caird Collection. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
www.rmg.co.uk
Category
Tool · Scientific instrument
Maker / attribution
Not established
Reference
AST0580
Catalogue / lot identifier
Source URL identifies the listing
Source-reported date
1813
Country
Not established

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

Physical Configuration and Materiality

The astrolabe (AST0580) is constructed from brass and measures 60 mm in diameter, with a total length of 93 mm. The instrument features a circular mater topped by a tri-lobed throne.

The throne is engraved with a Koranic verse. The rete is noted as having a design quality described by the museum as poor, featuring pierced openwork tracery and a central crossbar.

Evidence for this section
  • “Materials: Brass”
  • “Diameter: 60 mm”
  • “The small, plain tri-lobed throne bears a Koranic verse”
  • “the rete is of poor design”

Astronomical Components and Calibration

The mater contains a gazetteer documenting 24 localities. The instrument includes seven plates with markings for various latitudes between 21° and 40°, three of which are unlabelled.

The reverse of the instrument is fitted with a sine quadrant and a double shadow square. The outer limb features graduated scales and inscriptions.

Evidence for this section
  • “The mater contains a gazetteer with 24 localities”
  • “There are seven plates with badly engraved markings for various latitudes between 21° and 40°, three being unlabelled.”
  • “On the back of the instrument is a sine quadrant and a double shadow square.”

Dating and Chronology

The date is established through a Persian rim inscription. This text references the legend of Jamshid and functions as a chronogram indicating the year AH 1228, corresponding to 1813 AD.

The maker of the instrument is recorded as unknown.

Evidence for this section
  • “A Persian inscription along the rim, referring to the legend of Jamshid, forms a chronogram and also gives the date as AH 1228 (1813 AD).”
  • “Creator: Unknown”

Open research questions

  • What specific localities are included in the 24-entry gazetteer housed within the mater?
  • How does the 'poor design' of the rete specifically manifest?
  • Do the unlabelled plates exhibit blank surfaces or merely missing coordinate etchings?

Source evidence

Recorded claims and source quotations for Brass Astrolabe AST0580
FieldSource-reported valueSource quotation
Museum IDAST0580“ID: AST0580”
Date made1813 (AH 1228)“AH 1228 (1813 AD)”
MaterialsBrass“Materials: Brass”
Diameter60 mm“Diameter: 60 mm”
PlatesSeven plates“There are seven plates with badly engraved markings for various latitudes between 21° and 40°”
Museum IDAST0580“ID: AST0580”
CollectionCaird Collection, National Maritime Museum“Credit: National Maritime Museum, Greenwich, London, Caird Collection”

Visible details

  • Circular brass mater topped by an engraved tri-lobed throne, shackle, and suspension ring.
  • Brass rete with pierced openwork tracery, pointers, and central crossbar over an engraved plate.
  • Outer limb engraved with graduated scales and inscriptions along the circumference.

Research qualifications

  • The maker is recorded as unknown.
  • The gazetteer, individual plates, and reverse features (sine quadrant and shadow square) are concealed in this front view.

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

Consulted source

Astrolabe | Royal Museums Greenwich

Reviewed 2026-10-25 · Record 39f0fc0d37

Terms in this record

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

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