Wooden horary quadrant (25-cm radius) with painted scales and leather case, Islamic script, unsigned, Persia, 1701-1800. — view 1 of 3
View 1 of 3 · Image: Science Museum Group · original image source

Instruments · Horary quadrant

Wooden horary quadrant (25-cm radius) with painted scales and leather case, Islamic script, unsigned, Persia, 1701-1800.

DocumentedDocumented from the holding institution's catalogue record.
Maker / attribution
Unrecorded in source
Date
1701-1800
Country of origin
Iran (Persia)
Place
Iran, Iran
Object type
Horary quadrant
Dimensions
overall: 20 x 250 x 250 mm
Holding institution
Science Museum Group, London
Accession / object no.
1918-261
Credit line
Mrs Philiss D Lee
Catalogue title (original)
Islamic horary quadrant, Persian, 1701-1800

View the source record ↗

Record summary

Held and catalogued by Science Museum Group, London (object number 1918-261), this is a horary quadrant, made in Iran, Iran, Iran (Persia), dated 1701-1800. The Atlas places it in the Precision & Scientific Horology period (1750 – 1850) of its Instruments collection. Recorded dimensions: overall: 20 x 250 x 250 mm. The record is illustrated with 3 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

This unsigned Islamic horary quadrant was made in Persia (Iran) during the eighteenth century. Made of wood the quadrant has hand drawn painted scales and inscriptions. The horary quadrant was used for finding local time by sighting either the Sun or a bright star at night. Held vertically, a measurement could be taken from the position on the scale of a moveable bead on the thread of the plumb bob of the instrument. The horary quadrant was derived from the astrolabe and first appeared during the Medieval Period. Like its predecessor, it includes a two-dimensional depiction of a celestial sphere that is reduced to a quarter.

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.

Related records