Amavasya is the new-moon tithi that closes each lunar month, when the Moon catches up to the Sun and the night sky turns dark. It is the traditional day for Shraddha, Tarpan and other rites for the ancestors (Pitru), and for certain vrats such as Somvati Amavasya. Because a tithi is fixed by the angle between the Moon and Sun rather than by the calendar, the exact date shifts each month and can differ by location — this calendar lists the upcoming Amavasya dates for your city.
Amavasya is the fifteenth and final tithi of the waning Krishna Paksha — the moonless lunar day when the Moon and the Sun occupy the same 12 degrees of the zodiac. With almost no reflected sunlight reaching us, the Moon is not visible, which is why Amavasya is called the 'no-moon' day.
In the amanta calendar followed across much of India, Amavasya marks the end of the lunar month; in the purnimanta calendar of the north it falls in the middle of the month. Either way it returns about once every 29 to 30 days, and the civil date on which it is observed depends on which tithi is running at sunrise in your location.
Ruled by the Pitru, Amavasya is the classic day to perform Shraddha and Tarpan — offerings of water and food that honour departed forebears. Many families also keep an Amavasya vrat or fast, while new ventures are traditionally avoided on the darkened day. Certain Amavasyas through the year carry special weight:
Amavasya is chiefly observed for ancestral rites — Shraddha and Tarpan for the Pitru — and for vrats such as Somvati Amavasya. It is treated as a day for remembrance, charity and meditation rather than for starting new ventures, which are usually kept for a brighter tithi.
A tithi is defined by the angle between the Moon and the Sun, not by the calendar, so Amavasya returns roughly every 29 to 30 days on a shifting date. The day it is observed also depends on which tithi is running at sunrise where you are, so it can fall a day apart in different cities.
Somvati Amavasya is an Amavasya that falls on a Monday (Somvar). It is considered especially auspicious and is kept as a vrat, particularly by married women praying for the long life and welfare of their family.
For educational purposes. Astrological interpretations are traditional and not a substitute for professional advice.