User:Syncategoremata/Equatorium

EI² contains the following discussion of the equatorium:

s.v. "al-Kāshī", vol. 4, p. 703a

In 829/1426, he completed the second version of the Nuzhat al-ḥadāʾiḳ, in which he described an equatorium similar to that of Chaucer (see D. J. Price, The equatorie of the planets, Cambridge 1955); this, which he called a ṭabaḳ al-manāṭiḳ, was designed to determine the position of the planets by manual means; the first references to such an instrument appear in the work of the Hispano-Arab Azarquiel [see al-Zarḳalī]. In the same year he composed a Lawḥ al-ittiṣālāt, enabling the rapid calculation of linear interpolations. These two works are edited and translated by E. S. Kennedy, The planetary equatorium, Princeton 1960.

s.v. "Māshāʾ Allāh", vol. 6, p. 711ab

De receptione, preserved in Latin translation (ed. J. Heller, Norirbergae 1549), comprises 6 horoscopes dating between 791 and 794. One of them figures in the Peterhouse ms. 75.1, which contains the treatise Chaucer (ca. 1340–ca. 1400) on the equator (E. S. Kennedy, A horoscope of Messehalla in the Chaucer Equatorium manuscript, in Speculum, xxxiv [1959], 629–30; repr. in E. S. Kennedy (ed.), Studies in the Islamic exact sciences, Beirut 1983, 336–7; cf. Kennedy–Pingree, The astr. history, 175–8).

s.v. "Ulugh Beg", vol. 10, p. 813b

The most outstanding was Ghiyāth al-Dīn al-Kāshī [q.v.] who came from Kāshān in ca. 823/1420. He soon became a leading figure and invented several instruments for the observatory, most notably a planetary equatorium.

s.v. "ʿUṭārid (the planet Mercury)", vol. 10, p. 941a

Ptolemy's model therefore implies a non-circular deferent which was identified as an ellipse by the Toledan astronomer Ibn al-Zarḳālluh [see al-Zarḳālī], who used this curve for practical purposes in his treatise on the construction of the equatorium (W. Hartner, Oriens-Occidens, i, Hildesheim, 1968, 465–78; J. Samsó and H. Mielgo, Ibn al-Zarqālluh on Mercury, in Jnal. for the Hist. of Astronomy, xxv [1994], 289–96). This idea reached the Mashrīḳ, for it reappeared in the Taʿdil hayʾat al-aflāk written by Ṣadr al-Sharīʿa in 747/1347 (A.S. Dallal, An Islamic response to Greek astronomy, Leiden 1995, 120–1), while al-Kāshī (d. 832/1429), also in a treatise on the equatorium, uses two intersecting arcs of a circle as an approximation to an ellipse (E.S. Kennedy, The Planetary Equatorium of. . . al-Kāshī, Princeton 1960, 40–1, 170–2).

Glossary, s.v. "ṣafīḥa", vol. 13, p. 479

ṣafīḥa(A) : plate. IX 251b

ṣafīḥa shakkāziyya → shakkāziyya

ṣafīḥa zarḳālliyya (A) : in astronomy, an astrolabic plate serving the latitude of the equator, developed by two Andalusian astronomers in the 5th/11th century, Ibn al-Zarḳāllu and ʿAlī b. Khalaf. It differs from the ṣafīḥa shakkāziyya by its set of markings. IX 251b; XI 461b

ṣafīḥa zidjiyya (A) : in astronomy, the equatorium, called thus by al-Zarkali. His equatorium is totally independent and represents all the planetary deferents and related circles on both sides of a single plate, while a second plate bears all the epicycles. XI 461b

Glossary, s.v. "shakkāziyya", vol. 13, p. 501

shakkāziyya (A) : in astronomy, the term for the markings, consisting of two families of orthogonal circles, of a universal stereographic projection which underlies a family of astronomical instruments serving all terrestrial latitudes. IX 251b; an instrument that is apparently a simplified version of the ʿabbādiyya type, with only one complete grid of equatorial coordinates and an ecliptical grid limited to the great circles of longitude for the beginnings of the zodiacal signs on its face, while its back resembles that of a standard astrolabe. XI 461b

Glossary, s.v. "ṭabaḳ al-manāṭiḳ", vol. 13, p. 523

ṭabaḳ al-manāṭiḳ (A) : in astronomy, an equatorium designed to determine the position of the planets by manual means; the first reference to such an instrument appears in the work of the Hispano-Arab Azarquiel. IV 703a