How the Panchang Is Calculated

Computed from the sky, not from tables

Traditional almanacs once derived planetary positions from the arithmetic of the Surya Siddhanta. KaalPanchang instead computes the true geocentric longitudes of the Sun and Moon for the exact moment and place in question with a modern astronomical ephemeris (the same class of Meeus / VSOP-grade algorithms used by professional astronomy software). Because the panchang follows the real sky rather than an approximation, it is accurate to the minute.

The sidereal zodiac and the Lahiri ayanamsa

Modern (tropical) astronomy measures longitudes from the vernal equinox, which drifts about 50.3 arcseconds a year through precession. Indian jyotisha fixes the zodiac to the stars instead - the sidereal frame. The gap between the two is the ayanamsa. KaalPanchang uses the Lahiri (Chitrapaksha) ayanamsa, India’s official standard, which works out to roughly 24°12′ in 2026. Signs (rashi) and the 27 nakshatras are read in this sidereal frame; the tithi, being the angle between the Moon and Sun, is the same in either frame.

The five limbs, precisely defined

The word panchanga means “five limbs.” Each is a clean astronomical quantity:

• Tithi - the Moon’s gain on the Sun in 12° steps; the 30 tithis of the lunar month. The one running at your sunrise names the day.
• Nakshatra - the Moon’s sidereal longitude divided into 27 arcs of 13°20′.
• Yoga - the combined longitude of the Sun and Moon, likewise in 27 arcs of 13°20′.
• Karana - half a tithi (6°); eleven karanas cycle through the month.
• Vara - the weekday, reckoned from one sunrise to the next.

Tied to your sunrise and your city

A tithi or nakshatra begins and ends at a precise instant that is the same everywhere on Earth - but which one is “today’s” depends on what is running at your local sunrise, and sunrise depends on latitude, longitude and date. So the panchang is genuinely local. KaalPanchang computes sunrise and sunset - with atmospheric refraction - for your exact coordinates, frames the whole day from your sunrise to the next, and reports the limbs prevailing at that sunrise.

The lunar month and leap months

KaalPanchang follows the Amanta scheme, in which the lunar month ends at the new moon (Amavasya) - the convention across western and southern India. When a lunar month contains no solar ingress (Sankranti), it is a leap month and is flagged as Adhika Masa. The Vikram and Shaka samvat years are derived alongside.

The day’s windows: Rahu Kaal, Choghadiya, Muhurta

Rahu Kaal, Yamaganda and Gulika are fixed eighths of the daytime, assigned by weekday. The Choghadiya divides day and night into eight parts each; the thirty muhurtas divide them into fifteen each, with Abhijit the eighth muhurta around solar noon. All are proportional to your actual day length, so they shift with the season and your latitude rather than sitting at fixed clock times.

Accuracy and verification

Every figure is computed to the minute for the tithi, nakshatra, yoga, karana, sunrise and sunset, Rahu Kaal and the principal muhurtas - directly from the Sun’s and Moon’s positions, not from printed tables. Where a subtle model choice matters - for instance the longitude-difference definition used for planetary combustion (asta) - it follows the classical definition.