The Astronomical Observatories of Jai Singh c20.s1.5

c20.s1.5

On the astrolabe, the position of the sun on the ecliptic (its longitude), and its position for the day (its altitude) being known, the only operation required is to turn the ‘ankabūt (aranea), so that the part of the ecliptic in which the sun is, lies on the proper altitude circle (almucantarat), and then the rising sign, or the point of the ecliptic on the horizon, can be at once read off.