The Astronomical Observatories of Jai Singh c12.s1.18

c12.s1.18

Albīrūnī’s discussion of the position of Ujjain is of considerable interest. He writes⁴: “All canons of the Hindus agree in this that the line connecting Laṅkā with Meru divides the οἰκουμένη lengthwise in two halves, and that it passes through the city of Ujain, the fortress of Rohītaka, the river Yamunā,⁵ the plain of Tāneshar, and the Cold mountains. The longitudes of the places are measured by their distance from this line. On this head I know of no difference, except the following passage in the book of Āryabhaṭa of Kusumapura:—‘People say that Kurukshetra, *i.e.*, the plain of Tāneshar, lies on the line which connects Laṅkā with Meru, and passes through Ujjain. So they report on the authority of Pulīśa.⁶ But he was much too intelligent not to have known the subject better. The times of eclipses prove that statement to be erroneous, and Pṛithusvāmin maintains that the difference between the longitudes of Kurukshetra and Ujjain is 120 yojanas.’ These are the words of Āryabhaṭa. Ya‘ḳūb Ibn Ṭārik⁷ says in his book, entitled the Composition of the Spheres, that the latitude of Ujjain is 4⅓ degrees, but he does not say whether it lies in the north or south. Besides he states it, on the authority of the book *Al-Arkand*, to be 4⅓ degrees.⁸ We, however, found a totally different latitude of Ujain in the same book in a calculation relating to the distance between Ujain and Almanṣūra,⁹ which the author calls Brahmanavāṭa, *i.e.*, Bamhanwā, viz., latitude of Ujain, 22° 49′; latitude of Almanṣūra, 24° 1′. According to the same book, the straight shadow in Lohāniyye,¹⁰ *i.e.*, Loharāni, is 5⅝ digits. On the other hand, however, all the canons of the Hindus agree in this, that the latitude of Ujain is 24 degrees, and that the sun culminates over it at the time of the summer solstice.”