The Astronomical Observatories of Jai Singh c10.48

c10.48

Let *AB* (figure 36) be the edge of the Delhi gnomon, and *ABD* in the plane of the Delhi meridian. Let *ABE* make an angle δ with *ABD*, then *ABE* represents a meridian at a place whose longitude difference from Delhi is δ. Let *CX* denote the direction of the sun when it is in the Delhi meridian, then the arc *DP* will measure its declination; and if *CX₂* be the direction of the sun when in the plane *ABE*, then *EQ* will measure its declination. On the Niyat Yantra the semicircle *ABD* is not marked, but *ABE* corresponds to one of the masonry semicircles, each of which is graduated north and south from E for the purpose of observing declinations.