How the Vedic Drishti Panchang Is Calculated
Methodology for the Vedic Drishti Panchang: Swiss Ephemeris, Lahiri ayanamsa, local sunrise, and the exact definitions used for tithi, nakshatra, yoga, karana, Rahu Kaal, Choghadiya, Panchak and observances.
Ephemeris, ayanamsa and time
Positions of the Sun and Moon come from Swiss Ephemeris 2.10.03 using its data files (the server refuses to run on the lower-precision Moshier fallback). Longitudes are sidereal with the Lahiri (Chitrapaksha) ayanamsa. Each city uses fixed city-centre coordinates and its IANA time zone, so daylight saving time is applied abroad. Times are shown in local time with seconds dropped, the convention printed almanacs use.
The Panchang day and sunrise
A Panchang day runs from local sunrise to the next local sunrise. Sunrise and sunset are the moments the upper edge of the Sun's disc meets the horizon, with standard atmospheric refraction (1013.25 hPa, 15 °C) and no allowance for local terrain or altitude. Moonrise and moonset use the same convention. Some Indian almanacs time moonrise to the centre of the Moon's disc without refraction, which gives a moonrise about 4 minutes later and a moonset about 4 minutes earlier than ours.
The five limbs
- Tithi: each 12° of the Moon's elongation from the Sun. Tithis 1-15 are Shukla Paksha (ending with Purnima), 16-30 are Krishna Paksha (ending with Amavasya). The page names the tithi in effect at sunrise and every tithi that begins before the next sunrise, each with its end time.
- Nakshatra: each 13°20′ of the Moon's sidereal longitude, from Ashwini at 0°.
- Yoga: each 13°20′ of the sum of the Sun's and Moon's sidereal longitudes, from Vishkumbha.
- Karana: each 6° of elongation (half a tithi). The first half of Shukla Pratipada is Kimstughna; then Bava, Balava, Kaulava, Taitila, Gara, Vanija and Vishti (Bhadra) repeat eight times; the last three half-tithis are Shakuni, Chatushpada and Naga.
- Vara: the civil weekday of the date.
Change times are found by bisection to within about one second. Different almanacs apply slightly different apparent-position conventions, so tithi end times can differ from other sources by up to about a minute.
Rahu Kaal, Yamaganda and Gulika Kaal
Daytime from sunrise to sunset is divided into eight equal parts. The table gives the part (1 = first after sunrise) for each weekday.
| Weekday | Rahu Kaal | Yamaganda | Gulika Kaal |
|---|---|---|---|
| Sunday | 8 | 5 | 7 |
| Monday | 2 | 4 | 6 |
| Tuesday | 7 | 3 | 5 |
| Wednesday | 5 | 2 | 4 |
| Thursday | 6 | 1 | 3 |
| Friday | 4 | 7 | 2 |
| Saturday | 3 | 6 | 1 |
Abhijit Muhurat and Brahma Muhurta
Daytime is divided into 15 muhurtas; Abhijit is the 8th. It is traditionally not used on Wednesdays. The night from the previous sunset to sunrise is divided into 15 muhurtas; Brahma Muhurta is the 14th, ending one night-muhurta before sunrise.
Choghadiya
Daytime and night-time are each divided into eight equal Choghadiyas. The day sequence starts with the planet that rules the weekday and follows the order Sun, Venus, Mercury, Moon, Saturn, Jupiter, Mars; the night sequence starts with the ruler of the fifth weekday and moves two steps back each time. Amrit, Shubh and Labh are treated as auspicious, Char as neutral, Udveg, Rog and Kaal as inauspicious.
| Weekday | Day sequence | Night sequence |
|---|---|---|
| Sunday | Udveg, Char, Labh, Amrit, Kaal, Shubh, Rog, Udveg | Shubh, Amrit, Char, Rog, Kaal, Labh, Udveg, Shubh |
| Monday | Amrit, Kaal, Shubh, Rog, Udveg, Char, Labh, Amrit | Char, Rog, Kaal, Labh, Udveg, Shubh, Amrit, Char |
| Tuesday | Rog, Udveg, Char, Labh, Amrit, Kaal, Shubh, Rog | Kaal, Labh, Udveg, Shubh, Amrit, Char, Rog, Kaal |
| Wednesday | Labh, Amrit, Kaal, Shubh, Rog, Udveg, Char, Labh | Udveg, Shubh, Amrit, Char, Rog, Kaal, Labh, Udveg |
| Thursday | Shubh, Rog, Udveg, Char, Labh, Amrit, Kaal, Shubh | Amrit, Char, Rog, Kaal, Labh, Udveg, Shubh, Amrit |
| Friday | Char, Labh, Amrit, Kaal, Shubh, Rog, Udveg, Char | Rog, Kaal, Labh, Udveg, Shubh, Amrit, Char, Rog |
| Saturday | Kaal, Shubh, Rog, Udveg, Char, Labh, Amrit, Kaal | Labh, Udveg, Shubh, Amrit, Char, Rog, Kaal, Labh |
Panchak
Panchak is in effect while the Moon is in the last five nakshatra-divisions from Dhanishta pada 3 through Revati, that is from 300° to 360° of sidereal longitude. The page gives the start and end of the whole Panchak period when it overlaps the Panchang day.
Lunar month and Samvat
Lunar months are Amanta (new moon to new moon) and are named by the sidereal sign the Sun enters during the month: Mesha → Chaitra; Vrishabha → Vaishakha; Mithuna → Jyeshtha; Karka → Ashadha; Simha → Shravana; Kanya → Bhadrapada; Tula → Ashwin; Vrishchika → Kartika; Dhanu → Margashirsha; Makara → Pausha; Kumbha → Magha; Meena → Phalguna. A month without a solar ingress is Adhik (an extra month) and takes the name of the following month. The Purnimanta month used in North India is the next month's name during Krishna Paksha. Vikram Samvat is the civil year plus 57 from Chaitra and plus 56 for the months before it; Shaka Samvat is Vikram Samvat minus 135.
Vrat and festival rules
- Ekadashi Vrat: Ekadashi prevails at sunrise (Smarta rule; Vaishnava observance can fall a day later).
- Pradosh Vrat: Trayodashi prevails at sunset.
- Sankashti Chaturthi: Krishna Chaturthi prevails at moonrise.
- Vinayaka Chaturthi: Shukla Chaturthi prevails at midday.
- Masik Shivaratri: Krishna Chaturdashi prevails at the middle of the night.
- Purnima, Amavasya and Sankranti are listed when they occur during the Panchang day.
Regional and sampradaya traditions apply further rules, so a local temple calendar can differ by a day. Links from a day to devotional texts are marked as source-backed (a cited verse states the link) or editorial (a common custom).
Scope
These pages publish calculated astronomical and calendrical values with their definitions. They do not make predictions and do not rank one almanac above another. Report a discrepancy through the Vedic Drishti app.