Brass astrolabe with silver inlay
From Isfahan, Iran, AD 1712
Made for the last Safavid Shah of Iran, Sultan Husain (died
1722)
This astrolabe has seven latitude plates. The rete is marked
with pointers to sixty-three important stars and the mater is
inscribed with a gazeteer of 103 cities throughout the Islamic
world, including Jerusalem, Damascus, Baghdad, Kabul and Delhi.
Using the data provided in the gazeteer, an educated person could
calculate from each location the direction of Mecca, which Muslims
must face during daily prayer.
A calligraphic inscription at the top of the astrolabe praises
the royal patron, Sultan Husayn, at length. It is written in a
dense, elaborate style, and many of the metaphors are appropriate
to the astronomical instrument, describing the Shah as:
'…the centre of the sphere of power and justice, the pole of the
supreme heaven of magnificence and grandeur, the flashing star of
the apogee of the world conquest, the resplendent sun of the midst
of the heavens of world government.'
Two craftsmen have signed the back of the instrument, the
astrolabe-maker cAbd al-cAli ibn Muhammad
Rafi' al-Juzi'i, and his brother Muhammad Bakir, who carried out
the inscriptions.
The massive size and weight of this instrument show that it was
more for conspicuous ostentation than use. To measure the altitude
of a star, for example, an astrolabe must be lifted up (held by the
ring at the top) and held above eye-level – which would be quite
impossible with this particular object! Not long after its
production, possibly after Sultan Husayn died, in 1722, the
astrolabe was acquired for the British collector Sir Hans Sloane.
Shortly afterwards, the instrument changed hands again, when
Sloane's collection was acquired by the British Museum after his
death, in 1753.
K. Sloan (ed.), Enlightenment. Discovering the (London, The British Museum Press, 2003)
R.T. Gunther, The astrolabes of the world (Oxford University Press, 1932)
W.H. Morley, Description of a planispheric (London, Williams and Norgate, 1856.)
A. MacGregor (ed.), Sir Hans Sloane, collector, sc (London, The British Museum Press, 1994)
C.B.F. Walker, Astronomy before the telescope (London, The British Museum Press, 1996)