Panchāṅgam

How our Panchāṅgam is calculated

Last reviewed: 14 August 2026

The daily Panchāṅgam and muhūrta guidance on this site are computed for the San Francisco Bay Area in the spirit of a traditional almanac — no vague predictions, no sensational astrology, no advertising and no tracking. This page explains exactly how the figures are produced, so you can judge them for what they are.

What we compute

For each day we calculate the five limbs of the Panchāṅgam — tithi, nakṣatra, yoga and karaṇa, together with the vāra (weekday) — along with sunrise and sunset. It also shows the traditionally restricted starting periods (Rāhu Kālam, Yamagaṇḍam and Durmuhūrtam), the context-dependent Guḷika Kālam, and the traditional reference periods (Brahma Muhūrta, and Abhijit only when it does not overlap a restricted period), plus festival and vratam dates.

Convention and ayanāṃśa

We follow the Drik (observation-based) convention, using the Lahiri (Chitrapakṣa) ayanāṃśa — the most widely used sidereal reference in South Indian practice. We apply a linear approximation of the published Lahiri value rather than the full series; over the range shown here the two agree to within a few arc-seconds. Tithi, nakṣatra, yoga and karaṇa are derived from the true (apparent) longitudes of the Sun and Moon corrected by the ayanāṃśa.

Astronomy

Solar and lunar positions are computed from established astronomical formulae (based on Jean Meeus’ Astronomical Algorithms). Sunrise and sunset are found by stepping through the local civil day in two-minute intervals, computing the Sun’s altitude at each step from the same Meeus solar longitude, and interpolating the moment it crosses the horizon altitude. It is not the NOAA solar-position algorithm, but the result agrees with it to about a minute. The daily “kālam” periods (Rāhu, Yama, Guḷika) are derived in the traditional way — the daytime from sunrise to sunset is divided into eight parts, and the relevant part is assigned by weekday.

Technical disclosure

• Coordinates: 37.6624, −121.8747 (Pleasanton, CA); timezone America/Los_Angeles.
• Sunrise / sunset altitude: the standard −0.833°, allowing for atmospheric refraction and the solar disc.
• Ayanāṃśa: Lahiri (Chitrapakṣa), computed as a linear approximation of the published value (accurate to a few arc-seconds across the range above); convention: Drik (observation-based).
• Kālam method: the daytime is divided into eight equal parts between sunrise and sunset, and each period is assigned by weekday.
• Abhijit overlap: Abhijit Muhūrta is presented only when it does not overlap Rāhu Kālam, Yamagaṇḍam or Durmuhūrtam; on days where it overlaps, it is withheld rather than shown as usable.
• Validated reference range: January 1, 2026 through December 31, 2027 — the span of the curated festival and observance data. Beyond 31 December 2027 the astronomy still computes, but the dates have not been checked against a traditional reference; for anything after that date, please confirm with Gurukkal.
• Independent check, run on every build (from 31 August 2026): sunrise and sunset are compared against a second, separate implementation — the NOAA solar position algorithm, written out from the published equations in tools/verify_panchangam.js rather than shared with the engine. Across nine dates and locations, including both daylight-saving transitions and a leap day, the two agree to better than 0.1 minute. The Moon is checked against physical constraints instead of against a second copy of the same series: thirty tithis must average one synodic month (29.5422 d against 29.530588 d), twenty-seven nakṣatras one sidereal month (27.3246 d against 27.321582 d), and every tithi length must fall inside the range the Moon’s own speed allows. An earlier hand check on 12 August 2026 against a traditional Drik reference agreed within about ±3 minutes; the automated checks above are what run now. The same date returns identical values whether the device is set to Los Angeles, New York, London, Kolkata, Singapore or UTC.
• Known limitations: it does not evaluate a personal horoscope, Tārā Bala, Chandra Bala, lagna, planetary strength or combustion, ceremony-specific rules or family tradition. Each of those is recorded as a proposed, inactive rule in the site’s own muhūrtham ruleset, which names every one of them as not evaluated rather than quietly omitting it. The daily panel on the homepage computes for the Pleasanton reference location; the muhūrtham page computes for whichever location you choose.

Two layers, kept apart

Since 31 August 2026 the astronomy and the tradition live in separate files, because they are different kinds of thing. assets/js/panch.js computes positions: objective, testable, the same for everybody. assets/data/tradition-profile.js holds the interpretation — which periods are set aside, which tithis are avoided for beginning something, how Guḷika Kālam is treated. Every rule in it records where it came from and whether Sri Kumar Gurukkal has reviewed it, and the ruleset carries a version number that is stamped onto every recommendation the site gives. Rules he has not been shown do not run at all.

See it working on the muhūrtham page, which shows the reason for every window it offers and for everything it sets aside. The underlying ideas — what a tithi is, why sunrise decides the day, why two almanacs disagree — are explained in Sacred Learning.

Location and time

• Reference location: Pleasanton, California — latitude 37.6624, longitude −121.8747. Timings shift by only a minute or two across the immediate Bay Area, so other Bay Area cities are close but not exact.
• Timezone: America/Los_Angeles, with daylight saving handled automatically.
• Display: all times are shown in Pacific Time (America/Los_Angeles), regardless of the timezone your device is set to, so the figures always describe the Bay Area day.
• Accuracy: sunrise, sunset and the kālam boundaries derived from them are good to about ±1 minute. Tithi, nakṣatra and yoga transition times are good to roughly ±5 minutes: the lunar series is truncated to its largest terms and no ΔT correction is applied. Published almanacs may therefore differ from this tool by a few minutes, and by more where they use a different sunrise convention or ayanāṃśa.

Guḷika Kālam in Sri Kumar Gurukkal’s tradition

According to Sri Kumar Gurukkal’s tradition and practice, Guḷika Kālam is a context-dependent period rather than a general prohibition. Ordinary poojas and other ceremonies may be performed during this time. Certain death-related rites should not be begun during Guḷika Kālam. Please consult the priest responsible for the rite for final guidance. Applications can differ according to sampradāya, family custom and the nature of the rite. (Sri Kumar Gurukkal does not perform funeral rites; he does perform ancestral remembrance such as Śrāddha and Tarpaṇam.)

Why observances can differ

Two careful almanacs can legitimately differ. Festival dates and observances vary by location, sampradāya and the exact timing of the relevant tithi (for example, whether a tithi is current at sunrise, at midday or at moonrise). Where a date commonly differs, please treat this calendar as Bay Area guidance and confirm important observances with Gurukkal.

Automated guidance is not a personal muhūrtham

This is the most important point. The tool gives preliminary guidance — it is not a muhūrtham personally selected by Sri Kumar Gurukkal, and no date shown here should be read as “approved” by him. For a wedding, gṛha praveśam or any important ceremony, the exact muhūrtham must be confirmed with Gurukkal, who considers the family’s birth details, the ceremony and your tradition.

Specifically, this tool does not:

• select or approve a final Muhūrtham;
• replace a priest;
• perform a horoscope match;
• evaluate all family traditions or ceremony-specific rules;
• guarantee correctness or a result;
• provide medical, legal or financial advice.

Accuracy and corrections

The engine’s festival output has been checked against a traditional Drik reference and matches closely. Even so, an almanac is a serious thing: we warmly welcome review by qualified Panchāṅgam scholars, and we will correct anything found to be wrong. If you notice a timing or terminology discrepancy, please contact SaivaPriest.com with the date, location and the source you compared against. Important ceremony decisions should always be confirmed directly with a qualified priest. Please see Corrections & contributions.

View today’s full Panchāṅgam & festival calendar →