A brass astrolabe by Muhammad ibn Ahmad al-Battûtî, signed and dated A.H. 1170, Meknes, Morocco, circa 1757
- signed and dated A.H. 1170
- 15.7. diam.
23.5cm. max. height
An interest in traditional astronomy and astronomy continued in the Maghrib until the early 20th century, and this is a typical late Maghribî astrolabe with a simple variety of rete. However, it has some markings that are remarkable (if not fully understood).
The maker, known by at least eight other astrolabes and one quadrant, is named in an inscription on the back of the throne: "Praise be to God alone. Made by Muhammad ibn Ahmad al-Battûtî - may God be with him in this world and the next, Amen. (This is in) the year 1170 (?) [= 1757]." The date is written in the Maghribî forms of the "Hindu-Arabic" numerals, and the reading "7" is uncertain ("6" is also a possibility), but is inspired by the fact that his other astrolabes are dated between 1128 and 1151 Hijra, and he was clearly approaching the end of his career. Proof of his advancing years is provided by the fact that he omitted the word 'amal, "made by", in his original inscription and added the word above the line. (Such corrections are extremely rare in Arabic inscriptions). A predecessor of his, al-Hasan ibn Ahmad al-Battûtî, is known by at least three astrolabes dated between 1097 and 1106 Hijra.
The rete is in a form typical of Maghribî astrolabes (for another by the same maker see Gunther, Astrolabes, no. 147 - misdated). There are pointers for about 25 stars, some broken. The mater is devoid of markings.
There is only one plate with astrolabic markings, in this case altitude circles for each 6° and azimuth circles for each 10°, and special curves for the various prayers at nightfall, daybreak, after midday and around mid-afternoon. The markings are for 30°, serving Cairo and Sijilmasa, and 34°, serving Meknes, which is surely where this astrolabe was made.
The other plate is of a kind not attested on any other documented astrolabe. On one side there is a circular table giving the positions of the beginnings of the 28 lunar mansions relative to the 12 signs of the zodiac. Each mansion occupies about 13°: see the article "Manâzil al-Kamar" in Enc. Islam, 2nd edn. The table appears to have been conceived for four different sets of data, but only the information in the inner ring has been completed. The data given in the partially completed outer ring are identical to the corresponding entries in the inner ring. Because of the motion of precession, the mansions move slowly with respect to the ecliptic, and perhaps what we see here is the remains of four sets of values according to four different (unnamed) authorities in which most of the entries for a given mansion are identical (so that three of the four entries can be left blank) or differ by at most one digit.
The other side of that plate is also engraved with information in circular tabular form. At the centre the four seasons are marked in each quadrant. Around these are the signs of the zodiac and rather unhappily the names of the would-be corresponding Julian months. Outside these are the alphanumerical Arabic numerals (abjad) running from 1 to 9, 10 to 90, 100 to 900, and 1000. The 28 divisions serving these 28 letters provide space for the names of the 28 lunar mansions and a sketch of their principal stars. But in the rings inside and outside of this information there are two sets of magical names that defy explanation, save that some of them seem to be names for angels. Again, no parallels can be cited.
The back is typical of a late Maghribî astrolabe, with a solar - calendrical scale around the central markings. The latter consist of a sexagesimal (60x60) grid for trigonometrical calculations, a universal horary quadrant, and a double shadow square. The alidade is a replacement.
On Muhammad and al-Hasan al-Battûtî see Mayer, Islamic Astrolabists, pp. 60-61 and 46. For a history of astronomy in the Maghrib see King, "Astronomy in the Maghrib". For an ordered list of late Maghribî astrolabes see King, Synchrony, II, pp. 1010-12 and 1014-15.