The tithi, Nakshatra, yoga and karana
A tithi ends when the Moon's gain on the Sun reaches the next multiple of 12°; the app finds that instant to the second from the Sun and the Moon as it computes them, and its tithi ends agree with Swiss Ephemeris within 9 seconds on 60 days from 1950 to 2050.
The five limbs (panchanga) of a moment, as the app's TODAY and every page give them.
| Limb | Rule | How many |
|---|---|---|
| Tithi | the Moon's elongation from the Sun, in 12° steps | 30 in a lunar month |
| Nakshatra | the Moon's sidereal longitude, in 13°20′ steps | 27 |
| Yoga | the sum of the Sun's and Moon's sidereal longitudes, in 13°20′ steps | 27 |
| Karana | half a tithi, 6° of elongation | 60 in a lunar month (11 names) |
| Vara | the weekday of the sunrise at the place | 7 |
Each change is found by searching the instant the angle crosses its boundary, to the second, and printed with the seconds dropped, as almanacs print them ("upto 17:07"). Checked: the tithi and Nakshatra ends against Swiss Ephemeris within 9 seconds on 60 days from 1950 to 2050; the limbs of whole days against Drik Panchang.