Gnomonic shadow

Abstract

The hypotenuse of the gnomon (palaśruti) is obtained by taking the square root of the sum of 144 (bhavaka) and the square of the mid-day shadow [of the gnomon] on the equinoctial day (viṣuvaddina).1 The mid-day shadow on the equinoctial day when multiplied by the radius (triguṇa) and divided by that [hypotenuse] would be the Rsine of the terrestrial latitude (akṣamaurvikā).