Introduction
The English "hour" and the Sanskrit "horā" mean much the same thing: one hour of the day. In Indian tradition each hora has a planetary lord. When a panchang says "Jupiter's hora is running now", it means Jupiter rules this hour.
B. V. Raman, in Graha and Bhava Balas, describes the hora as one 24th of the day, and notes that the Hindu day begins at sunrise and runs until the next sunrise. So the first hora is the first hour after sunrise, not after midnight.
The weekday page shows how the order of the weekdays itself comes from the horas. This page looks at the hora more closely: its length, its use in muhurta, and hora bala in a birth chart.
The order of the hora lords
The lords of the horas always come in this order:
Sun → Venus → Mercury → Moon → Saturn → Jupiter → Mars, then the Sun again.
Where does it come from? Raman writes that, following the Surya Siddhanta, Saturn is farthest from the Earth, then Jupiter, Mars, the Sun, Venus, Mercury and, nearest, the Moon. Stepping through this list by distance gives the hora order.
The first hora of every day belongs to that weekday's lord. Sunday's first hora is the Sun's, the second Venus's, the third Mercury's, and so on to the 24th, which is Mercury's. The 25th, Monday's first, is the Moon's. In this way every weekday opens with its own lord's hora.
How long is a hora?
Two methods are in use, and it helps to know both.
- Equal horas: divide the time from sunrise to the next sunrise into 24 equal parts. Each hora is about 60 minutes. Raman counts hours this way when computing hora bala.
- Separate day and night horas: many panchangs divide the day (sunrise to sunset) into 12 parts and the night into 12. Then in summer a day hora is longer than 60 minutes and a night hora shorter.
In both, the order of the lords is the same; only the clock times shift by a few minutes. So if two panchangs show slightly different hora times, don't worry: they may follow different methods. ePandit's panchang always counts horas from sunrise in your selected city.
Hora in muhurta
The Muhūrta-cintāmaṇi (Śubhāśubha-prakaraṇa 55–56) speaks of the kāla-horā. Its gist: if work prescribed for a particular weekday is needed on another day, it may be done in the hora of that weekday's lord. Work considered fitting for Thursday, for example, can be done on another day in Jupiter's hora.
The same verse adds that matters such as the direction (dik-shoola) are still to be checked. So the hora is a helping factor, not a full muhurta. The tithi, nakshatra, yoga and the rest of the panchang are read with it.
In everyday practice many people like Mercury's or Jupiter's hora for starting study and the Moon's hora for travel. These are preferences of tradition, not rules whose breaking spoils anything.
Hora bala in the birth chart
The hora has a use in the birth chart too. In shadbala, part of "kala bala" is hora bala: according to Raman, the planet ruling the hour of birth receives 60 shashtiamsas of hora bala. For this the weekday of birth and the hours from sunrise to birth are used.
It is a small part of shadbala. On its own it decides nothing about a chart.
The hora of the day and the 'hora' division are different
The word "hora" has another meaning in astrology: half of a sign. The Muhūrta-cintāmaṇi's Vivāha-prakaraṇa says one hora is fifteen degrees, two to a sign. That is a chart division (D2).
The hora of the day (an hour) and the hora of a sign (15°) are two different things that share a name. This page is about the hora of the day.