Astrolabe Catalogue

astrolabe, inventory number 47792 from Turkey, ca. 1800
thumbnail for astrolabe (front), inventory number 47792 from Turkey, ca. 1800
thumbnail for astrolabe (back), inventory number 47792 from Turkey, ca. 1800
thumbnail for astrolabe (rete front), inventory number 47792 from Turkey, ca. 1800
Dateca. 1800
MakerShaykh Sakkūt
Inventory no.47792
AcquisitionPurchased from the Hotel Drouot, Paris, in 1992

This instrument is one of only a handful in the collection that has the Syrian calendar on it. Although the months of the Syrian calendar correspond roughly to those in the Christian calendar, the year begins in the autumn rather than the spring. On this circular scale, the first month (تشرين) is located to the right of the central line at the bottom. The months then progress clockwise around the scale.

The central band contains the zodiacal signs, written in red. Aries (حمل) is at the top, just to the left of the central line. Normally, the Syrian months do not correspond exactly to the zodiacal signs. On this instrument, however, each month equates to a sign.

The innermost circle, however, is something of a mystery. One suggestion is that it represents the length of the longest day in each month. This seems problematic, as the numbers steadily decrease through the year and are not longest in June. Another possible explanation is that this is the date of a new or full moon in each month. This might make sense of the decreasing number each month, as the phases of the moon slowly fell behind the solar calendar.

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Throne, Ring and Shackle

The throne is of the simple, engraved type made of wood attached with integrated base made of wood . More information


The mater and limb are of two pieces, nailed construction. The limb is brokenin the upper left quadrant, ca. 45° from the throne. The edge of the limb was coloured red. The metal tab that holds the plates stationary is located at the bottom of the instrument, i.e., 180° from the throne. Scales on the limb: degree scale. More information


The back contains 12 scales of the following types: Altitude; Sine/Cosine; Shadow square; Unequal hours; Calendar; Cotangent; Zodiacal signs; Lunar cycle. More information

Rete, Nut & Bolt

The rete contains 23 stars. The zodiac on the rete is labelled: illegible , illegible , illegible , illegible , اسد , سنبله , ميزان , عقرب , قوس , جدى , دلو , حوت .
The rete is attached using a nut & bolt. The wingnut and bolt look like later replacements. More information


There are 11 plates with latitudes ranging from to 90°0' . More information

Rules & Alidades

Type Details
AlidadeDouble-ended. The sighting vanes have broken off, and so it is impossible to know if they had pin-hole sights.
More information


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