Bharatiya Jyotihshastra (History of Indian Astronomy), translated by R. V. Vaidya v2.c14.18

v2.c14.18

Patvardhan tells people simply the time of birth and gives a brief reading, but nobody is able to say how he is able to do this. Hence they are unable to appreciate the importance of his art. Some people even think that the time of birth can be found by means of siddhi or psychic power developed through mantras. But this is wrong. The method of finding the ascendant at birth by observing simply the physical traits may be called sāmudrik (Palmistry). But the sāmudrik of Patvardhan has a close connection with astrology. It is the author's experience that many of the events, past and future, told by Patvardhan are found to be correct. But this branch of knowledge has not yet been completely mastered by him. Rules must be framed after verifying hundreds of cases. Patvardhan is mainly interested in finding ascendant at birth by observing physical traits. But even then, an instance may be cited where the ascendant could not be definitely given, where it remained doubtful : but such instances are few and far between. Again at times, the time of birth goes wrong by a year, a month, or a day ; and this is due to a very trivial cause. Jupiter stays in a sign for one year ; but it is not necessarily the case that it enters a new sign just in Caitra ; it may be found to occupy the same sign during two Śaka years. For example, Jupiter will occupy the sign Leo both during Śaka 1818 and 1819. The sun remains in the sign Meṣa both in Caitra and Vaiśākha. The same is the case with other months. The moon occupies a sign for about 2½ days. Hence, if an attempt is made to find the time of birth simply from the planetary positions in signs, the above error is sometimes likely to occur. Patvardhan knows how to find the planetary positions in terms of degrees in a sign. If these degrees are referred to the almanac there would be no room for error. If he attempts to tell the time of birth after carefully consulting the almanac, it is sure that his answer would be found to be correct in the case of at least 8 out of 10 horoscopes.