Muhurta and daily windows

Muhurta (muhurta) — a unit of Indian time equal to one thirtieth of a day. A day divides into 30 muhurtas, each lasting about 48 minutes. The same word also names the choice of a favourable moment for an undertaking — "taking a muhurta" means picking the right hour for a task; in that sense, muhurta is a whole field of practice. This section is an overview: it covers both meanings, plus the windows of the day that tradition tracks apart from the muhurtas themselves — favourable and unfavourable — and how to read their names. If you've come across "Rahu Kala," "Yamaganda," or "Abhijit" in the daily forecast, look for the explanation here.

What a muhurta is

Muhurta is an astronomical unit of time going back to the Vedas. Daylight divides into 15 day muhurtas, darkness into 15 night muhurtas. At the equinox each muhurta is ≈ 48 minutes; the rest of the year, day and night muhurtas are unequal to each other and shift with latitude and season.

The word "muhurta" comes from a Sanskrit root meaning "instant," "short stretch of time." In classical Sanskrit muhurta is not simply "half an hour" (as it is sometimes translated), but a self-standing unit with its own place in the system.

Not to be confused with hora: hora divides the day differently — into 24 planetary hours, one per each of the seven grahas in a fixed Chaldean order. Planetary rulers are a property of the hora, not of the muhurta.

Windows of the day

Besides the muhurtas themselves, tradition marks daylight and darkness with other windows. They are not nested inside muhurtas — they are independent divisions of the day that are read on top of the muhurtas:

Daylight divided into eight equal parts (does not coincide with the division into muhurtas):

• Rahu Kala (rahu-kala) — an unfavourable window connected with the shadow of Rahu. One eighth part, different for each day of the week; the window's length is about 90 minutes.
• Yamaganda (yamaganda) — another unfavourable window, connected with Yama, the same length as Rahu Kala.
• Gulika (gulika) — an unfavourable window of the same length, connected with the shadow graha Gulika (son of Saturn).

The muhurtas tradition singles out on their own:

• Abhijit (abhijit) — the 8th of 15 day muhurtas, around the middle of the day's arc. Held to be one of the best moments for important undertakings — except Wednesday: tradition does not recognise Abhijit that day, and the panchanga marks the window as inactive.
• Brahma Muhurta (brahma-muhurta) — the second-to-last, 14th of 15 muhurtas of the night, before the Sun rises. Connected with meditation and sadhana.

Separate layers of dividing the day:

• Hora (hora) — a planetary hour: 1/12 of daylight or 1/12 of darkness (24 horas a day) ruled by one of the seven grahas; not a muhurta, but its own layer of dividing the day.
• Sandhi (sandhi) — transitional windows at the day's three junctures (sunrise, noon, sunset), neutral or calling for particular conduct.

The panchanga shows the time of each window; knowing them helps in choosing a favourable moment for an undertaking.

Combined muhurtas

There are also other favourable yogas of the day, which form not from dividing time but from a combination of vara and nakshatra:

• Sarvartha Siddhi (sarvartha-siddhi) — a combination favourable for most worldly matters, when the day's vara coincides with one of the nakshatras fixed to it.
• Amrita Siddhi (amrita-siddhi) — a narrower and stronger combination of the same type, favourable for important undertakings and long matters.

A separate system: Choghadiya

Choghadiya (choghadiya) — not part of the Vedic muhurta system, but a separate regional system of dividing day and night into eight periods, widely used in Western and Northern India.

How to read this section

Each window is a separate page. The page gives a definition, its place in the system, the calculation, and its practical meaning. Neighbouring windows are linked through "Related terms" — a convenient way to move on to the panchanga as a whole and to Tara Bala, which adds a personal layer to any window.

As you read, keep in mind: each window has its own nature (auspicious, neutral, inauspicious), its own duration, and its own calculation. The day and night halves of the day have different sets of windows. And, of course, a window is a background — it speaks to the general quality of the moment, not to what exactly you are doing.