Astrolabe, by Muhammad ibn Fattuh al-Khamairi, Seville, 1224/5

A fine astrolabe of the maghrebi, North African style. Two of its plates have the name Marrakesh and Fez added above the latitude by an unexperienced hand, showing that a possible owner, at a certain point of the object's life, decided to add this extra information, likely for the two plates she/he used the most.

Parts

It comprises: a mater; a rete, 5 plates, a horse and pin, an alidade.

Throne

The throne is of the simple type, attached with a integrated base. This throne is composed of two pieces: the front, which is integrated with the limb, and the back, which is an extension of the back plate. The front features a decorative motif and the back the maker's signature.

Ring

The ring is a hook of the simple, round cross-section type.

Shackle

Shackle of the eye-bolt type. The large eye-bolt attaches to a bracket, which then attaches to the throne.

Mater

The mater and limb are of one-piece construction. The rim is marked with a degree scale 0-360° divided every 5 degrees, subdivided every degree, and labelled in Abjad numerals every 5 degrees. It is engraved as a tablet of ecliptical co-ordinates (i.e. for latitude 66 1/2°).

Womb

Contains a table of ecliptic coordinates.

Back

The back contains 8 scales: two altitude scales on the upper half of the rim 0-90°, divided every 5 degrees, subdivided every degree, labelled every 5 degrees in Abjad numerals and notched on the left-hand side; a zodiacal calendar divided in 30 degrees labelled in Abjad numerals every 5 degrees on top of each sign; a Julian calendar with a scale of the days of the month, is divided every 5 days, subdivided every day, and labelled every 5 days plus the last day; a prepetual calendar for a 28-year cycle.

The back also contains a shadow square in the central, lower half, both the the left and right sides are divided into 12 fingers vertical and 12 fingers horizontal, labelled every 2. The lower left and lower right quadrant of outer circle features a double cotangent scale 15-40 fingers labelled every 3 until 24 and then every 4.

Rete

The rete is of the Maghrebi type with hook star pointers some with inverted-heart bases and some with silver rivets at the bases. A circle connects the Tropic of Capricorn to the band of the equator. There are 4 silver knobs for rotation. It features 29 stars.

Zodiac label

The zodiac on the rete is labelled: الحمل , الثور , الجوزا , السرطان , الاسد , السنبله , الميزان , العقرب , القوس , الجدي , الدلو , الحوت.

Pin and horse

The rete is attached using a nut and bolt. A small, square nut thread on to an equally small bolt. The head of the bolt has a small pointer extending from it. The shank of the bolt is square and fit into the square hole on the alidade. This ensured that the pointer on the front of the instrument was always colinear with the alidade on the back.

Alidade

Double-ended. The sights that were originally on this alidade have since broken off and are now missing.

Plates

There are 5 plates with latitudes 31°, 32°, 33°, 34°, 35°, 36°, 37°, 38° and 40°. They are engraved with almucantars for every 3 degrees, azimuths for every 5 degrees, 12 unequal hours labelled in both Abjad numerals and words and 5 lines of Muslim prayers. They are marked المشرق (east) and المغرب (west).Two of its plates have the name Marrakesh and Fez added above the latitude by an unexperienced hand, possibly an owner. The numbers of the unequal hours are spelled out in words.