The mater and plates of a rare Ottoman astrolabe made of wood and paper,
undated (possibly 18th-Century), signed Hasan Husni Bakshahri, wood and glazed paper -- 5¾in. (15cm.) diameter, 7¼in. (18.5cm.) high, 5/8in. (1.7cm.) thick
Islamic astrolabes made of wood are rather rare, and this is the first to pass through these rooms. A similar piece was described by Dominique Brieux for an auction at Drouot in Paris on June 2, 1992, and is now in the Museum of the History of Science at Oxford. This piece is missing its rete, which doubtless disintegrated and was discarded. The remaining parts, however, attest to the competence of the maker, Hasan Husni Bakshahri, whose name is new to the modern literature. The epithet Bakshahri indicates that the maker or his family hailed from Beg Shahr (Byzantine Karallia) near Antalya (G. Le Strange, Lands of the Eastern Caliphate, London, 1905, pp. 151-152). The piece was probably made in some Ottoman provincial city in Anatolia, since various features noted below exclude an Egyptian provenance and there is no plate for Istanbul.
The front of the mater bears no markings, and the outer scale is divided for each 1° in 5° intervals, starting from the top and bottom and running to 90° on each side.
The back bears a double scale for the shadows in the upper left quadrant showing the horizontal and vertical shadows (labelled al-zill al-mabsut and al-zill al-mankus) for solar altitudes on the outer scale which run from 0° to 90° (from the top to the side). The gnomon length is taken as 12 units (standard) and the scales are divided in 3-unit divisions subdivided in single units. The double scale is unusual but superfluous (a single scale would suffice), and the arrangement of the altitude scale is awkward. The upper right quadrant contains standard trigonometric markings to base 60, with additional semicircles on the axes for finding sines and cosines, a quarter-circle radius 24 units for finding the solar declination, and two perpendicular lines at 12 units on each axis and a radial line at 45° for finding the solar altitude at the beginning of the afternoon prayer. The semicircle below the horizontal diameter contains a double universal horary quadrant, with the hour-curves labelled zamaniyya for the seasonal hours. Both outer scales run from 0° at the bottom to 90° at the sides: within the left one there is solar declination scale with maximum value 23°28' (mayl kulli), a standard Ottoman value for the obliquity of the ecliptic; and within the right one there is a scale for finding the solar altitude at the beginning of the afternoon prayer ('asr awwal) as a function of the solar meridian altitude.
A calendrical scale is arranged in a circle inside the horary quadrants: it displays the dates in the Syrian calendar when the sun enters each Zodiacal sign: Aries, March 20; Taurus, April 21, etc. Some of the month-names reflect European influence (mart, mayis and aghustus) and are identical to those on a late Syrian quadrant now in the British Museum (Christie's London Sale Catalogue 13.12.1996 lot 599). The maker is identified in a cartouche to the left of the calendrical scale: rasm ... , "drawn by Hasan Husni Bakshahri". The elegantly-fashioned alidade is prominent and bears square viewers.There are ten plates, all carefully executed and containing more geographical information than is usual on Ottoman astrolabes, presented with what might be labelled a provincial naivete. Some names are difficult to read (particularly those in red ink), others have not yet been identified. Also the astronomical markings are different on the various plates, sometimes featuring azimuth curves, these occasionally below the horizon, sometimes with the prime vertical extended below the horizon. On some plates the construction lines for the azimuth curves are clearly visible. The data is here organized according to increasing latitude (this list is not definitive).
1a 0° (inscription obscure)
2a 22° Sus, Aswan (see below), Banjawr (?)
3a 23° Asyut (!, correctly closer to 27°, see below)
4a 24° Medina, Mansura, Nahlawara, Somnath
5a 27° Hurmuz, Minya, Ikhmim, and two others not identifiable
6a 28° Fayyum, Qulzum, Quzdar (in India)
4b 30° Damietta, Cairo, Zuweila, Nishapur (!, correctly closer to 36°)
7a 33° Salamis, Sefad, Sidon, Acre, Beirut, Benyas, Damascus, Baal-bek, Homs, Madayin, Baghdad, Rzkan (?), Nahrawan), and various cities in India including Peshawar, Salkot, Lahore, and others not identifiable.
8a 34° Tripoli, Krak des Chevaliers, Salamiya, Antioch, Malabar, the Island of Bani 'Amr, Samarra, Shirwan, Hulwan, Hamadan
9a 39° Znkyar (?), Aqshehir, Aqsaray, Qyrshhr (?), Qaysariyya, Sws (?), Arznkan (?), ??, Bukhara, ??, ??
8b 40° Toledo, ??, Ankara, Tuqat, Ikhlat, Bab al-Abwab (Darband), ??, Erzerum, Bardaa, Kanja
2b 44° Balanjar (see below)
3b 45° Birjan, Samandar
10a horizons for each 1° latitude between 51° and 62°
The geographical data is a mixture from the standard Iranian, Egyptian and Ottoman traditions, with additions from an unidentified Indian tradition and one fictitious name (Island of Bani 'Amr) inserted from the independent tradition of Islamic sacred geography. The city of Balanjar was destroyed in the 8th Century but featured prominently in the Iranian geographical tradition for centuries thereafter. The names Aswan and Asyut are both written with "sh" for "s", which excludes an Egyptian provenance for the piece.
See Colour Illustrations