Astrolabe: dismounted obverse

This astrolabe is a later (perhaps 16th century) copy of an original instrument, dated AH750 (1349-50 AD), by Ja'far ibn 'Umar al-Kirmani, a well-known instrument maker from 14th century Isfahan. That it is not an original piece is testified by the sloppy calligraphy, a mistake in the signature and the fact that the maker could not reproduce all the star names correctly. Nevertheless, this instrument is historically important because it documents the authentic piece from which it was copied, albeit in a partly degenerate manner.

The throne is low, plain and triangular shaped: reminiscent of kirmani astrolabes, though much simpler. The mater is cast in one piece with the throne and the limb. The geographical gazetteer in the mater, covering 23 localities with longitude, latitude and qibla, has impressively reproduced the original data in a surprisingly accurate manner. The rete has 22 star pointers and the two plates are crudely engraved. On the back of the instrument in the top right-hand quadrant is the following inscription: 'Ja'far ibn 'Umar [text: 'sr] ibn Dawlatshah al-Kirmani made it in the year 750 of the Hijra'. The alidade, bearing neither inscriptions nor scales, is probably a replacement.