Paksha (or pakṣa: Sanskrit: पक्ष), refers to a fortnight or a lunar phase in a month of the Hindu lunar calendar.
Literally meaning "side",. a paksha is the period either side of the Full Moon Day (Purnima). A lunar month in the Hindu calendar has two fortnights, and begins with the New moon, (Amavasya). The lunar days are called tithis and each month has 30 tithis, which may vary from 20 – 27 hours. A paksha has has 15 tithis, which are calculated by a 12 degree motion of the Moon. The first fortnight between New Moon Day and Full Moon Day is called Shukla Paksha, the period of the brightening moon (waxing moon), and the second fortnight of the month is called Krishna Paksha, or the period of the fading moon (waning moon).
Shukla paksha refers to the bright lunar fortnight or waxing moon in the Hindu calendar. Shukla (Sanskrit: शुक्ल) is Sanskrit word for "white".
Shukla Paksha is a period of 15 days, which begins on the Shukla Amavasya (New Moon) day and culminating Poornima (Full Moon) day and is considered auspicious.
Numerous festivals are held during this period, including the Navratri festivals, most importantly Chaitra Navratri and Ashvin Navratri.
Krishna paksha refers to the dark lunar fortnight or waning moon in the Hindu calendar. Krishna (Sanskrit: कृष्ण) is Sanskrit for "dark". Krishna Paksha is a period of 15 days, which begins on the (Full Moon) day (Purnima), culminating on (New Moon) day (Amasvasya). Krishna Paksha is considered auspicious, as the moon loses light during this period.
Festivals during Krishna Paksha are:
In Vedic astrology when a person does a prasna (a question chart) and the planet Venus indicates the time period, the event referred to in the answer will happen in a pakṣa (fortnight) from the time the question was asked.