An elegant Safavid brass astrolabe, signed by the celebrated craftsman Muhammad Khalil Ibn Hasan 'Ali, and decorated by Muhammad Mahdi al-Yazdi, Persia, Isfahan, dated 1085 AH/1674-75 AD

cast brass, hammered and engraved with elaborately designed cusped throne, containing six plates and a finely designed foliate rete, small bird-head terminal holding the pin with the large alidade in place, two hooks at top with suspension cord

In good condition, the rete and body with some patches of oxidisation, pin, alidade and horse replacements, as viewed.
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inscriptions

The name of the maker of this splendid astrolabe has been preserved for us in a rhymed inscription in a cartouche under the centre of the back:

'Made by the one needy (of the mercy and forgiveness) of God, the Most Sublime, the son of Hasan ‘Ali, Muhammad Khalil'.'

In a cartouche on the lower back is the statement that the piece is 'decorated by Muhammad Mahdi al-Yazdi.' All of the main engraving is in a beautiful decorative naskh script. Some expressions (such as some of the star-names) are presented in what one might label Persianised Arabic.

Both these men are well-known members of the prolific school of instrument-making that flourished in seventeeth-century Isfahan. The former is known by some two dozen astrolabes, and the latter by several astrolabes which he decorated for the former. No systematic study has been made of these instruments, now preserved in museums from Iran to Europe to North America. This also holds for other productions of this school, although model descriptions of a few individual pieces have been published by William Morley in 1856 (British Museum), a century and a half later, by Dr. François Charette (Greenwich). Only a basic overview of the identities of the Safavid craftsmen and their oeuvre, characterised by its elegance and mathematical accuracy, has been published (King, World-Maps, pp.262-9). A detailed survey of their astronomical features, inscriptions and decoration, let alone a technical investigation of the mathematical markings and metallurgical analysis of the composition would be most worthwhile.

The front of the throne is adorned with fine floral decoration, rather than the well-known 'Throne Verse' from the Qur’an, in which the relationship of God to heaven and earth is expounded, and which features on some of the maker’s other astrolabes.

On the rim is a lengthy and complex inscription invoking blessings on The Prophet Muhammad and the 12 Shi’a imams, listed in succession with all of their epithets, and skilfully arranged to fill the available space, ending with the date 1083 AH/1672 AD. The appearance of this date at the end of this inscription that is two years prior to the date of completion of the astrolabe itself is curious but should arouse no suspicion. It just reveals how little we know about the process of construction and decoration of these instruments.

On the back of the throne in another cartouche is the enigmatic inscription:

al-Husayn minnî wa-anâ min Husayn, 'Husayn is from me, and
I am from Husayn', or perhaps 'Husayn is from my stock, and I am from his'. This is a statement associated with the fourth Caliph, ‘Ali Ibn Abi Talib, stressing the closeness of his son, the martyred Husayn (known as sayyid al-shuhada), to himself, and hence also to The Prophet.

This inscription is rare on Safavid astrolabes - this writer has not seen it on any other - but it is attested on various qibla-indicators from Safavid Isfahan (King, World-Maps, pp.260-2).

The rete is relatively simple but distinguished by an upper equatorial bar corresponding to the standard lower one. The ecliptic ring is wide with with names of the zodiacal signs engraved and the scale divided for each 3° within each sign. The fonds of foliation that constitute the star-pointers are marked only with the names of the appropriate stars. These are (in four quadrants, reading counter-clockwise from the vernal equinox) as follows:

kaff al-khadib
dhanab qaytus shamali
dhanab qaytus janubi
fam qaytus
masafat al-nahr
ghul
sadr qaytus
‘ayn al-thawr / al-dabaran
rijl (al-jawza’) al-yusra
‘ayyuq
rijl (al-jawza’) al-yumna

——-

shi’ra yamaniya
taraf al-safîna
shi’ra shamiya
fard al-shuja’
qalb al-asad
qa’idat al-batiya
janah al-ghurab

——-

simak a’zal
simak ramih
nayyir fakka
‘unuq al-hayya
qalb al-asad
ra’s al-hawwa’

——-

waqi’
nasr ta’ir
minqar al-dajaja
dhanab al-dajaja

An unusual feature are the two contiguous semi-quatrefoils between the upper ecliptic ring and the upper equatorial bar. Quatrefoils are attested, albeit rarely, on Islamic instruments over the centuries, and appear to have been originally adopted from Byzantine astrolabes (King, World-Maps, p. 368, n.7, and Synchrony, II, pp.963-991).

The mater is engraved with circular scales presenting the longitudes (al-tul) and latitudes (al-‘ard) and qibla-directions and associated quadrants (al-inhiraf and al-jiha) of some 33+16 localities (al-bilad). Such gazetteers were common on Safavid instruments, and various significant examples have been published in their entirety (King, World-Maps, and Charette 2003).

The six plates are engraved with labelled altitude circles for each 3° and azimuth circles for each 10°, and serve the following latitudes (given with the corresponding lengths of maximum daylight).

2a    22;0° 13;22h
1b    30;0 13;53
3a    31;0 1[4];7
5a    32;0 14;7
4a    33;0 14;6
2b    34;0 14;17
1a    36;0 14;28
3b    37;0 14;34
4b    38;0 14;42
6b    42;0 15;5
5b    [66°] for conversion of celestial coordinates (equatorial and ecliptic)
6a    serves the horizons for all latitudes from 10° to 66° (corresponding to the Arctic Circle)

                        10 18 26 34 42 50 58 66

                        12 20 28 36 44 52 60

                        14 22 30 38 46 54 62

                        16 24 32 40 48 56 64

The declination scales are marked al-mayl kulli, 2° labelled for each 2° up to 24°. The expression al-mayl kulli for the maximum solar declination, which is the obliquity of the ecliptic, is a good example of Persianised Arabic; correctly in Arabic one would say al-mayl al-kulli, the maximum declination, and in Persian mayl-i kulli.

The plate for 38° has also azimuth curves below the horizon and some plates have the ordinal numerals for the seasonal hours engraved in words. The plate for 32° would serve Isfahan, but it bears no indication of this.

The back is decorated with the standard markings of a Safavid astrolabe:

In the upper left there is a universal horary quadrant showing circular arcs for each of the six seasonal hours (khutut sa’at mu’wajja). This ingenious device for quick determination of the time approximately was invented in ninth-century Baghdad in various forms, and was used on astrolabes for a millennium.

In the upper right there is a solar quadrant, with scales at either side for entering the solar longitude. Again such devices appear on astrolabes and quadrants in the ninth and tenth century. On the left we have: dawa’ir ansaf al-nahar fi l-‘urud al-marquma fi atrafiha, '(arcs of) circles representing the solar meridian altitude for the latitudes marked at the ends', for latitudes 26°, 29, 32, 35, 38, 41, 44°. With these curves one can determine the midday altitude of the sun at these latitudes throughout the year. On the right we have: khutut sumut al-qibla fi l-bilad al-madhkura fi atrafiha ‘ala irtifa’ al-gharbi, 'the curves corresponding to the western solar altitude in the azimuths of the qibla in those localities marked at the ends (of the curves): Kufa, Baghdad, Hamadhan, Basra, Isfahan, Yazd, Mashhad'. With these curves one can determine for any time of the year the solar altitude when the sun is in the direction of Mecca at any of these localities.

Below the centre is a double shadow square (cotangents and/or tangents) for bases (gnomon length) 12 digits (asabi’) and 7 feet (aqdam). These correspond to the shadow scales on the outer circumference. The annular scales in the lower half display for each of the 12 signs of the zodiac (al-buruj), the associated planets (al-kawakib), astrological limits (al-hudud) and faces (al-wujuh), as well as the 28 lunar mansions.

The alidade with sights, pin and horse are replacements that could be used only for holding the components of the instrument together and for sighting celestial objects. The alidade itself is non-functional, lacking as it does the scales that would serve the markings in the upper left and right of the back.

An astrolabe also signed by the instrument make Muhammad Mahdi al-Yazdi, date 1060 AH/1650-1 AD, is in the Nasser D. Khalili Collection of Islamic Art, inv.no.SCI161 (Rogers 2007, p.245 and Farhad and Bagci 2009, pp.180-1, no.51). A further astrolabe by Muhammad Khalili Ibn Hasan 'Ali, of similar size and quality (although with the addition of some silver inlay), was sold in these rooms 8 October 2008, lot 169.

Sotheby’s are grateful to Professor David King for his assistance in cataloguing this lot.

bibliographical notes

Apart from Morley, 'Astrolabe of Shah Husayn II' (1856), reprinted in Gunther 1932, the best source for detailed descriptions of some seventeenth-century Isfahan astrolabes is Charette 2003. On Muhammad Khalil and Muhammad Mahdi al-Yazdi see Mayer 1956, pp.54-57 and 64. On Safavid geographical gazetteers see King, World-Maps, pp.170-186, and Charette, cited above.