The Astronomical Observatories of Jai Singh c15.s2.t1.5

c15.s2.t1.5

(2) An armillary sphere of five circles, viz., the ecliptic, colure, great circle of latitude, the meridian, and the small circle of latitude. The ecliptic, meridian and small circle of latitude were graduated down to minutes, and the last mentioned was furnished with an alhidade, or sighter. A sighting tube appears to have been used on the alhidade (see figure 68).