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Hora Calculator (Planetary Hours)
A hora is a planetary hour. The day from sunrise to sunset has twelve horas and the night twelve more, each ruled in turn by the Sun, Venus, Mercury, Moon, Saturn, Jupiter and Mars. Astrologers use the hora to pick a time that suits the task — Mercury’s hora for study and trade, Jupiter’s for ceremonies, and so on.
How horas work
The first hora after sunrise belongs to the lord of the weekday — that is how the weekdays got their names. The following horas run in the traditional (Chaldean) order of planetary speed: Sun, Venus, Mercury, Moon, Saturn, Jupiter, Mars, and around again. Day horas are one-twelfth of the time from sunrise to sunset; night horas one-twelfth of the night.
Seven horas in, the sequence reaches the lord of the next weekday at the next sunrise — a neat check that the system is consistent.
Frequently asked questions
How long is a hora?
One-twelfth of the day or night, so it is close to 60 minutes only around the equinoxes.
Which hora is good for starting a business?
Tradition favours the horas of Mercury (trade), Jupiter (growth and wisdom) and Venus (prosperity), avoiding Rahu Kalam.