Bharatiya Jyotihshastra (History of Indian Astronomy), translated by R. V. Vaidya v2.c12.s9.16

v2.c12.s9.16

The compilers of the almanacs, published by Ganpat Krishnaji and the Nirnaya Sagar Press, calculate the rise and set of only Venus on the basis of the Kālāṃsas of the Grahalāghava. The times of the rise and set of all other planets in these almanacs and even those of Venus in other almanacs following the Grahalāghava system, are calculated by a crude method given by the Grahalāghava. Other almanacs in this country may be finding the rises and sets of planets on the basis of Kālāṃśas given in the works which they may be adopting as their authority. The new almanacs compiled with the help of the Nautical Almanac viz. the Keropanti i.e. Patwardhani Pañcāṅga that by Daivaji at Varanasi and our sāyana almanac find the times of the rise and set on the basis of kālāṃśa figures given by some ancient work or other. Not all the timings thus calculated are found to be correct in the case of any almanac. Some of them are correct and some are not. Now it is true that they are not as often wrong in the case of the new almanacs as in that of the old ones.