The Astronomical Observatories of Jai Singh c6.s1.t1.68

c6.s1.t1.68

³ A British Museum astrolabe dated A.H. 1070 (=A.D. 1659-60), by Muḥammad Muqīm of Lahore, gives the same table. Al-Battānī gives 86° 36′ and Nallino gives the following note: “ Ḥabash in suo astronomiæ libro narrat partem excedentem revolutionis (*fazl al-daur*), scilicet quantitatem (gradibus expressam) qua Solis totus ambitus 365 dies excedit, inventam esse ab astronomis khalifae al-Ma’mūn :— In specula al-Shammāsiyyah . . . . . 86° 43′ 39ⁱⁱ 36ⁱⁱⁱ 47ⁱᵛ Damasci in urbe . . . . . . 86° 41′ 25ⁱⁱ 14ⁱⁱⁱ 9ⁱᵛ a Yaḥy'a ibn Abī Manṣūr . . . . . 86° 35′ 13ⁱⁱ 46ⁱⁱⁱ In tabulis suis Habash primam quantitatem recepit, rotunde scribens 86° 43′ 39ⁱⁱ 37ⁱⁱⁱ, vel, gradibus in tempus conversis, 5ʰ 46ᵐ 54ˢ 36ᵗ etc.” *Opus Astronomica*, i. pp. 42 & 211. The present length of the tropical year expressed in mean time is 365 days 5 hours 48 minutes 45·5 seconds. or 365·2422 days nearly.