Tithi
तिथि
Lunar day: each 12° of the Moon's elongation from the Sun.
Definition
A tithi is the time the Moon takes to gain 12° on the Sun in longitude, so a synodic month holds thirty tithis, fifteen in each pakṣa. Because the Moon's speed varies, a tithi lasts between roughly 19 and 26 hours and does not coincide with the civil day. In general usage the tithi prevailing at sunrise names the day, and the tithi of birth is used to mark birthdays in the lunar calendar.
Articles that use this term
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A map of India's classical knowledge traditions, from the Vedas through the six Vedangas to the applied sciences, and where Jyotish sits among them.
7 min read · 17 October 2026
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Zero as a placeholder, zero as a number, and the astronomers who needed both to compute the sky.
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The five limbs of the Indian almanac, what each one measures, and how to make sense of a printed page.
7 min read · 15 October 2026
- PanchangaExplainer
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Twelve degrees between Sun and Moon: how the tithi is defined, why it varies in length, and why festivals follow it.
6 min read · 14 October 2026
- SiddhantaExplainer
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7 min read · 12 October 2026
- Panchanga
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From the ritual sutras to the Muhurta Chintamani: how the tradition thinks about doing an act at a fitting moment.
7 min read · 5 October 2026
- PanchangaExplainer
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Diwali is fixed by the Moon, not the Sun: by the new Moon that closes Ashwina, by the evening it covers, and by the Lakshmi Puja window inside that evening.
7 min read · 3 October 2026
- PanchangaExplainer
Ekadashi: the eleventh lunar day
Why a lunar year has 24 Ekadashis and sometimes 26, and why smarta and vaishnava almanacs can print different dates for the same one.
7 min read · 2 October 2026
- PanchangaExplainer
Navratri, twice a year: Chaitra and Sharad
The two nine-night festivals of the goddess, at the spring and autumn turns of the year, and the rules almanacs use to fix their first and last days.
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- PanchangaExplainer
Sankranti: the Sun's twelve sign entries
Why Makar Sankranti stays near 14 January while Diwali wanders, how the twelve sankrantis are classed, and the slow drift that will move the date.
6 min read · 26 September 2026