The Astronomical Observatories of Jai Singh c6.s1.t1.66

c6.s1.t1.66

The table gives *n*(87° 33′ 6″)—*a*.360° where *n* ranges from 1 to 9 and from 10 to 90 and *a* is a whole number.² Now 87° 33′ 6″, expressed in time, is 5 hours 50 minutes 12·4 seconds, and the length of the tropical year was supposed to be 365 days 5 hours 50 minutes 12·4 seconds.³ 14. The face.—(*Wajh* or Venter).—The inside surface (*venter*) of most of the astrolabes is engraved with a list of cities and their latitudes and longitudes and, sometimes, their position relative to Mecca.¹ The last is indicated by the *inḥirāf* or ‘inclination’ and the *masāfat* or ‘distance’ and *jihat* (side or point of the compass). The *inḥirāf* is the arc of the horizon intercepted between the meridian of the place and the vertical circle passing through the zenith of Mecca.² The Masāfat is the distance of Mecca measured along a great circle, and the *jihat* is the quarter of the horizon in which Mecca lies.