Lunar phase (Hinduism)


In Hinduism, each lunar phase has religious and astrological significance. There are four principal lunar phases: the new moon, first quarter, full moon, and last quarter, when the Moon's ecliptic longitude is at an angle to the Sun of 0°, 90°, 180°, and 270° respectively. Hindu astrology also considers significant the changes in the phase of the moon even during the course of each individual day.

New moon

The first of these principal phases is Amāvásyā, the day of the new moon.

''Paksha'' fortnights

The second and fourth phases are less significant, marking only the midpoints of the Paksha, the fourteen days on either side of the full moon. There are two pakshas: the first is the 'brightening' of the moon, as it changes from new to full; the second is the 'darkening', as it changes from full to new.
The first day of a paksha is called a Pratipada or Prathama and thus there are two of these days.

Full moon

The third phase is Pūrṇimā, the day of the full moon.

Calendrical significance

In the pūrṇimānta māna Hindu lunisolar calendar used in most parts of the Indian subcontinent, the lunar month starts on the day following the full moon and therefore Amāvásyā always falls in the middle of the month. However, in the amānta māna calendar used in some places, the lunar month starts on the day of the new moon, making Amāvásyā the last day of the lunar month in those places. Many festivals, the most famous being Diwali, are observed on Amāvásyā.

''Tithi'': lunar phase change in a single day

In Vedic timekeeping, a tithi is a "duration of two faces of moon that is observed from earth". Every day of a lunar month is called tithi. This concept is significant in astrology as it maps to the moment of birth.