Astrolabe, by Khalil Muhammad and `Abd al-A'imma, Persian, c. 1700

Parts

It comprises: a mater, a rete, 7 plates, an alidade, a horse and pin, a cord ('ilaqa).

Throne

The throne is of the indo-persian, pierced type and it is attached with a integrated base. Pierced with four scrolls, the throne bears inscriptions on both sides with the "throne" verse of the Koran (Sura 2, verse 256) on the front and the maker's signature on the back.

Ring

The ring is of the simple, squared cross-section type (i.e. a simple ring made from a round rod or piece of metal).

Shackle

Shackle of the omega type (i.e. Ω-shaped shackle). Decorative tabs and a pin attach the shackle to the throne.

Mater

The mater and limb are of one-piece construction. The tab to keep the tympans in place is located at the bottom of the instrument, 180° from the throne. The rim is marked with a degree scale 0-360° divided every 5 degrees, subdivided every degree, and labelled in Abjad numerals every 5 degrees. The rim is engraved with inscriptions.

Womb

The womb is engraved with a gazeteer showing the longitude, latitude, inhraf and jiha of 46 places.

Back

On the back are a sine and cosine graph on which is super-imposed an unequal-hour diagram; the arcs of the signs of the zodiac with graphs of the altitude of the sun for latitudes 28°, 30°, 32°, 34°, 36°, 38°, 40° and 42°, and of the azimuths of the Qibla for Baghdad, Basra, Isfahân and Tûs; a shadow-square within which is an astrological table of triplicities; an astrological table of the signs of the zodiac with limite and faces of the planets; cotangent scales; and the usual scales of degrees. At the bottom of the back near the edge is a Persian inscription, "This is a record which will outlast us, for life is by no means unlimited".

Rete

The rete is a replacement. It is crudely cut-out and drawn. There are construction marks visible throughout, such as the radial lines delimiting the zodiacal houses cutting across the ecliptic and the outer tropic band. The star-pointers are not labelled. The script differs in style and execution from the rest of the instrument. It features about 20 star-pointers none of which is named.

Zodiac label

The ecliptic circle is divided every 6 degrees, subdivided every 2 degrees, and labelled in Abjad numerals every 6 degrees. The zodiac is labelled: الحمل , الثور , الجوزا , السرطان , الاسد , السنبله , الميزان , العقرب , القوس , الجدي , الدلو , الحوت.

Pin and horse

The, horse, and pin seem to be replacements. The horse has the unusual shape of a horse with a duck on its back.

Alidade

Double-ended alidade. It seems to be a replacement.

Ilaqa

Attached to the suspension ring is an ilaqa of faded red silk.

Plates

There are 6 plates for latitudes 11°, 29°; 20°, 26°; 22°, 30°; 27°, 40°; 32°, 34°; 36°, 37°; 36° and a tablet of horizons;. The plates are probably replacements contemporary with the rete.