Reading the Panchang: The Five Limbs and the Arithmetic Behind Them

Panchang means "five limbs," and the name is exact: it is five separate measurements of the sky for a given day and place, not a mystical almanac. Four of the five are defined by the angular relationship between the Sun and the Moon, and the fifth is simply the weekday. Once you know that, the Panchang stops being a list of unfamiliar words and becomes readable — each limb is answering a precise astronomical question.

This guide defines each limb by what it measures, so that a figure on a Panchang page can be traced back to an angle rather than taken on trust.

The engine underneath: the Sun–Moon angle

Almost everything in the Panchang follows from one quantity — the difference in ecliptic longitude between the Moon and the Sun, measured in the sidereal zodiac. Call it the elongation. It runs from 0° at the new moon (Sun and Moon together) through 180° at the full moon and back to 360°. Tithi, Yoga and Karana are all just this angle sliced at different intervals; get the two longitudes right and the three fall out of arithmetic. That is why an accurate Panchang depends first on accurate positions — the periodic series for the Sun and Moon from Meeus's algorithms, applied with the Lahiri ayanamsa.

1. Tithi — the lunar day (Sun–Moon elongation ÷ 12°)

A Tithi is the time the Moon takes to gain 12° of elongation on the Sun. Thirty of them make a lunar month: fifteen in the waxing fortnight (Shukla Paksha) from new to full moon, fifteen in the waning fortnight (Krishna Paksha) from full back to new.

Because the Moon's speed varies, a Tithi is not a fixed number of hours — it can run from about 19 to 26 hours, which is why a Tithi can occasionally be skipped or repeated across two sunrises. The Tithi in force at sunrise is the one that names the day.

Some Tithis carry standing associations: Pratipada for beginnings, Panchami for learning, Ekadashi for fasting, Purnima (full moon) and Amavasya (new moon) for worship and ancestral rites respectively.

2. Nakshatra — the Moon's mansion (Moon longitude ÷ 13°20′)

The second limb is simply which of the 27 Nakshatras the Moon occupies — its sidereal longitude divided into 27 equal bands of 13°20′. The Moon crosses roughly one Nakshatra per day, so the day's Nakshatra changes at a definite clock time when the Moon leaves one band for the next.

Electional astrology (Muhurta) leans heavily on this limb: Rohini and Pushya are among the most auspicious for beginnings, Ashwini for travel and treatment, Revati for new undertakings. Each Nakshatra has traditional favoured and unfavoured activities.

3. Yoga — the summed longitude (Sun + Moon, ÷ 13°20′)

Yoga is the most misunderstood limb because it sounds like the postural practice and is unrelated to it. Here it is the sum of the Sun's and Moon's sidereal longitudes, divided into 27 parts. Where Tithi and Nakshatra track the Moon relative to the Sun and to the zodiac, Yoga tracks the two bodies moving together, and it advances a little faster than one unit per day.

There are 27 named Yogas. A handful are traditionally auspicious — Siddhi, Amrita, Shubha — and a few, such as Vyatipata and Vaidhriti, are avoided for important work.

4. Karana — the half-Tithi (elongation ÷ 6°)

A Karana is half a Tithi — 6° of elongation — so there are two per Tithi and 60 across the lunar month. There are only 11 distinct Karana names: four "fixed" ones that occur once each per month around the new moon, and seven "movable" ones that repeat in rotation. Karana refines timing within a day and matters most in detailed Muhurta selection.

5. Vara — the weekday and its planet

The simplest limb: the day of the week, each ruled by a planet, defining the day's baseline character.

Rahu Kalam — a derived, not observed, window

Every day carries a roughly 90-minute window called Rahu Kalam, traditionally avoided for starting anything important. It is not an observation of Rahu — Rahu is a computed point, not a body that "arrives." It is a calendrical division: the daylight span from sunrise to sunset is cut into eight equal parts, and a fixed part is assigned to Rahu depending on the weekday. The window therefore shifts with your local sunrise and with the length of the day, which is why it must be computed for a place, not read off a national table.

The related windows Yamaganda and Gulika Kalam are derived the same way, from the same eightfold division, assigned to different parts by weekday.

How to actually use a Panchang

An honest note on Muhurta

The five limbs are astronomy and can be computed exactly; this site does. The claim that a given Tithi or Nakshatra makes an undertaking succeed or fail is tradition, not measurement, and it should be read as the accumulated convention of Muhurta rather than as a law of cause and effect. The calendar is real; the electional meaning attached to it is a practice you can take or leave.

Today's Panchang

Our daily Panchang computes all five limbs, plus Rahu Kalam, Yamaganda and Gulika, for your location — using the same Sun and Moon positions that drive the Kundali engine, so the Tithi and Nakshatra you see here agree with the ones in a birth chart cast for the same moment.