Special Exhibition Label: 'Al-Mizan: Sciences and Arts in the Islamic World' (26/10/2010 - 20/03/2011)
This unique astrolabe has been split into its two halves to reveal in the mirror the geared calendar mechanism normally hidden inside. Made in Isfahan in 1221/2 by Muhammad ibn Abu Bakr, it is the oldest gearing to survive in a complete state.
The presence of the internal gear train makes the astrolabe thicker than normal. Rather than leaving the wide rim blank it has been decorated with silver-inlaid pictorial representations of the signs of the zodiac, alternating with warrior figures.
The combination of astronomical mechanism and elaborate ornament indicates that this was an extremely important commission. The inscription running round the circumference of the back plate proclaims the instrument's significance and profundity:
'This is an astrolabic disc, which can show you: a crescent moon, which progressively waxes and then returns to its waning phase; the celestial bodies of the sun and moon, when they are in opposition or in conjunction; and the points on their paths in a given year or month or at this moment. This disc is the product of the endeavour of someone learned in the technical arts, which are based on precision and scientific proof. Behold the disc! It will show you many of the wonders that prove the wisdom of the Merciful; its different motions are by virtue of a single mover, and it has meanings going beyond all meanings.'
MHS inv. 48213
The mechanism and displays of the back plate (here on the right) have been computer-animated for this exhibition and can be seen on the screen opposite.
- Relationship between astrolabe and calendar
- Astronomical mechanisms
- Oldest in the world
- Geared astrolabe inscription
- Inventory no. 48213 - Former Display Label
- Exhibition Label - 'The Moon'; National Maritime Museum, 19 July 2019 - 5 January 2020