Tajika Nilakanthi

A classic 16th-century Sanskrit treatise on Tajika astrology, which incorporates Perso-Arabic influences into Indian astrology.

The result obtained by division is the Spashta-gati true daily motion of the Moon. Example: To divide 48,000 by the total remaining portion of the Nakshatra Uttara Bhadrapada (64 minutes, 54 seconds), first convert the divisor into seconds (3894). To facilitate this, multiply the dividend by 60 as well, resulting in 2,880,000. Dividing this by 3894 gives a quotient of 739 with a remainder of 2334. Multiply the remainder by 60 and divide again to get 35. Thus, the Moon's motion is 739 minutes and 35 seconds (12° 19' 35") per day. || 19 ||

Upajati Meter—The half-duration of the day or night, minus the elapsed time of day or night, is the Eastern Nata. Conversely, the elapsed time of day or night minus the half-duration is the Western Nata. || 20 ||
original: "पूर्व नतं स्याद्दिनरात्रिखंडं..."

After calculating the true positions of the planets, it is necessary to determine the house divisions (Bhava Spashta). Since the houses are derived from the Ascendant and the Midheaven (10th house), we first describe the calculation of Nata hour angle or distance from the meridian to find the Midheaven.

Eastern Nata of the day occurs from midnight until midday. Western Nata of the day occurs from midday until sunset. For the night, Eastern Nata lasts from sunset until midnight, and Western Nata lasts from midnight until sunrise.

If the desired time (Ishtakala) is before noon, subtract the desired time from the midday point (half-day duration); the remainder is the Day Eastern Nata. If the desired time is after noon but before sunset, subtract the midday point from the desired time; the remainder is the Day Western Nata. If the desired time is after sunset but before midnight, subtract the desired time from the midnight point (half-night duration); the remainder is the Night Eastern Nata. If the desired time is after midnight but before sunrise, subtract the midnight point from the desired time; the remainder is the Night Western Nata.

Note: Subtracting the Nata from 15 the standard 6-hour quadrant in Indian time units gives the Unnata (altitude), but since Unnata is not required here, it has not been detailed. These Nata values will be used to calculate the 10th house.

Example: Here, the desired time is 13 ghatis and 54 palas. The midday point is 16 ghatis and 31 palas. Subtracting the desired time from the midday point leaves 2 ghatis and 37 palas. This is the Day Eastern Nata. || 20 ||

Anushtup Meter—Multiply the elapsed or remaining degrees of the Sun (including the precession of the equinoxes) by its respective rising sign value. Divide by thirty; the resulting elapsed or remaining portions of the Sun should then be set aside. || 21 || For the desired minutes and seconds—