[ N T R 0 0 U C T [ (0 N The Carldranchayagapitar edited here critically for the first time, from original manuscripts, with Translation and auto-commentary, is an interesting astronomical manual by Nilakantha Somayaji, a reputed mediaeval astronomer of Kerala (c. 143-1545 A.D.) Chayagarita or 'Computations concerning the Shadow' constitutes the Hindu astronomer's method for ascertaining the exact time of occurrence of any event on the basis of the shadow cast by the Sun or the Moon. The expediency of this device during ancient and mediaeval times would be apparent when one considers the limitations of such chronometrical devices as the hour-glass, water-disc, etc. The gाmom101, being one of the simplest of astronomical instruments that could be set up at any time and at any place, and readings made independent of circumscribing factors like 2ero-point etc., is the most handy instrument to record such abrupt 0ccurrences as the birth of a child, death of a person and setting in of the initial menstruum . A knowledge of the exact m10ument of these happenings, as computed by astronomical Imethods from the measure of the shadow, facilitates the prediction of the future based on them in accordance with the dictums of astrology Obviously, the shadow cast by the Sun is measured during day and that by the Moon during might The utility Clayagapita in the daily life of the mediaeval Hindu whose prescribed way of life required the performance of numerous religious rites, is not far to seek. (Ordinary astronomical computation enabled him to calculate auspicious times (null॥rta) for sacred rites and ms of time-units like 1alkds and wina lkds, say, after sumrise or sunset. But, in the absence of accurate chrom10umeters. it was not easy to ascertain when that auspicious moment, as calculated had arrived. Chayagapita came to his rescue in such a situation. For, it was possible to calculate , In advance, the length that the Sun's or the Moon's shadow would attain at the appointed time. One could, then, wii
