﻿266 ON THE ASTRONOMICAL COMPUTATIONS 



•* and Chandra ; the first quotient will be half the 

 " duration of the eclipse in dandas and pahs ; and the 

 " second quotient will be half the vimardardha dura- 

 " tion in dandas and pahs" occ. The cticharma, or 

 portion of the disk eclipsed, is here found in de- 

 • grees and minutes of a great circle : it ma)' also be 

 estimated in digits ; but the angidas or digits of the 

 Hindus are of various dimensions in different books. 



The beginning, middle, and end of the eclipse 

 may now be suposed found for the time in Hindu 

 hours; when it will happen after midnight ; but, for 

 the corresponding hour of the civil clay, which begins 

 at sunrise, it is further necessary to" compute the length 

 of the artificial day and night; and, for this purjpose, 

 be known rn • uyanansd or distance of the vernal 

 equinox frbm the first of mt ha, the sun's right recen- 

 sion and declination; which several requisites shall be 

 mentioned in their order. 



Respecti rig the precession of the equinoxes and 

 place of the cohire, the following is a translation of all 

 I caa find op the subject in the Surya Siddhanta and 

 its commentary : — 



Text. '.< The ayanansa moves eastward thirty times 

 " twenty in each Alalia Yug ; by that number (600) 

 " multiply the ahapgaua (uumber of mean solar days 

 " for which the calculation is made) and divide the 

 " product by the sa-van days in a Vug, and of the quo- 

 <c ticnt take the l>hu/a, which multiplv by three, and 

 '• divide the product by ten; the quotienr is the ayan- 

 " a sa. With the avanans a correct thsgraka, cranti, 

 *' the clihaya* cliuradula, and other requisites to find 

 " the push ti and the two vishuvas. When the carna 

 " is less than the surya cJiluiya, the pracchacra moves 



