Nepali patro, tithi and Rahukaal explained

What a Nepali patro contains

• Vikram Sambat dates, usually with Gregorian (AD) alongside.
• Tithi for each day, with its ending time.
• Nakshatra, and often the yoga and karana — the rest of the panchanga.
• Festivals and observances in the Nepali calendar.
• Auspicious timings (saita) and the daily Rahukaal.
• Sunrise and sunset, which everything about the day is reckoned from.

Tithi: the lunar day, not the solar one

A tithi is defined by angle, not by time. Take the Moon's longitude, subtract the Sun's, and every completed 12° of that difference is one tithi. Thirty tithi make a lunar month: fifteen in the waxing fortnight (shukla paksha) and fifteen in the waning (krishna paksha).

Because the Moon's speed varies — it is faster near perigee, slower near apogee — the time it takes to gain 12° varies too. A tithi can run roughly 19 to 26 hours. That has two consequences a reader has to hold on to:

1. 1A tithi does not start at sunrise or at midnight. It starts whenever the Moon completes that 12°, which can be the middle of the afternoon.
2. 2A tithi can be skipped or repeated relative to solar days. If a tithi begins and ends between two sunrises, it does not "own" any day; if it spans two sunrises, it appears on two dates.

Rahukaal: an eighth of the daylight, not a clock time

Rahukaal is derived mechanically. Take the period from sunrise to sunset, divide it into eight equal parts, and one of those parts is Rahukaal — which part depends on the weekday.

Everything about that calculation is local. Sunrise and sunset depend on your latitude and longitude and on the date. In Nepal, day length varies noticeably between Poush and Jestha, so the eighth of daylight is a different number of minutes in winter and in summer, and it starts at a different clock time.

A printed table that gives "Rahukaal 10:30–12:00 on Monday" is therefore an approximation for one reference place at one time of year. Software that knows your location computes the actual window — which is what the Nepali patro in Jyotish Sarathi does.

Reading the patro for muhurta

1. 1Start from the tithi and its ending time, not from the date label. If the work must fall inside a particular tithi, you need the window, not the day.
2. 2Check the nakshatra in force during that window — it changes on its own schedule.
3. 3Avoid Rahukaal for the specific hours it occupies that day in your place, rather than for a remembered slot.
4. 4Confirm sunrise, since vara and several other rules are reckoned from it rather than from midnight.

Why the patro should come from the same engine as your kundali

Tithi and nakshatra come from planetary longitudes, and those depend on the siddhanta and the ayanamsha. If you read a panchanga from one source and cast charts in another program with different settings, the nakshatra in your calendar can disagree with the nakshatra in your chart, and nothing tells you which to trust. Computing both from one setting removes the ambiguity — see the methodology.