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Instruments · Astrolabe

Astrolabe, Islamic world, 1701-1800

DocumentedDocumented from the holding institution's catalogue record.
Maker / attribution
Unrecorded in source
Date
1701-1800
Country of origin
Islamic world
Place
North Africa, North Africa
Object type
Astrolabe
Holding institution
Science Museum Group, London
Accession / object no.
1986-1190
Credit line
Herve Chayette and Laurence Calmels
Catalogue title (original)
Islamic astrolabe, 1701-1800

View the source record ↗

Record summary

Held and catalogued by Science Museum Group, London (object number 1986-1190), this is an astrolabe, made in North Africa, North Africa, Islamic world, dated 1701-1800. The Atlas places it in the Precision & Scientific Horology period (1750 – 1850) of its Instruments collection. The record is illustrated with 4 photographs.

Assembled from the source record's structured fields. Dates and attributions are given as the source states them; where a field is missing the Atlas leaves it blank rather than estimating.

Catalogue description

Science Museum Group description

Made in the eighteenth century, this brass Islamic astrolabe was made in the region of North Africa known as the Maghrib. This front view shows the moveable fretwork plate called the rete that denotes star positions by wavy pointers. The astrolabe is in essence a model of the universe that an astronomer could hold in their hands. Popular in Medieval and Renaissance Europe, its many uses included timekeeping, astrology and surveying. The astrolabe is a two-dimensional depiction of the heavens whose layout is achieved using the mathematical technique of stereographic projection. From its origins in the Ancient World, Islamic astronomers developed the astrolabe from where it spread to Europe.

Historical context

Precision & Scientific Horology (1750 – 1850)

Harrison solves longitude; Mudge invents the lever; Breguet's Paris workshop defines the modern watch.

The longitude problem was solved by the marine chronometer and lunar distance methods; dividing engines made precision scales possible, and observatories set time by transit instruments.

Read the period in the timelineMore instruments from this periodEarlier: Early Modern Horology

Atlas type guide

Astrolabes, quadrants and astronomical compendia

The planispheric astrolabe is a two-dimensional model of the sky. A pierced rotating star map (the rete) turns over a plate engraved for a particular latitude; by aligning a star or the sun with its observed altitude, the user can read the time of day or night, the time of sunrise and sunset, and solve many other astronomical problems. Developed in the Hellenistic world and refined by astronomers in the Islamic world from the eighth century, it reached Latin Europe through al-Andalus.

Quadrants, compendia, armillary spheres and later orreries belong to the same family of instruments that model the heavens. They were teaching tools, status objects and practical time-finders. Many surviving examples are signed and dated, which makes them important evidence for the history of instrument-making workshops in Baghdad, Isfahan, Lahore, Toledo, Louvain, Nuremberg, London and elsewhere.

What to look for

  • The latitudes engraved on the plates — they show which cities the instrument was made for.
  • The script and calendar used: Arabic or Persian inscriptions, abjad numerals, Hebrew or Latin text indicate tradition and region.
  • The design of the rete: the number of named stars and the style of the star pointers changes by region and period.
  • Shadow squares, unequal-hour lines and zodiac scales on the back (dorsum).
  • Signatures, dedications and dates, often hidden on the throne (kursi) or the back.

Dating clues

  • Signed and dated astrolabes allow precise dating; undated ones are attributed by star positions on the rete, which shift slowly through precession.
  • Gothic-style retes with tracery are typical of European instruments of the fourteenth and fifteenth centuries.
  • Printed paper astrolabes and planispheres became common from the sixteenth century onward.

General guidance written by the Atlas editors about this kind of object. It is not a statement about this particular piece; for that, rely on the source record above and on physical examination.

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