01What Sankashti Chaturthi is
Sankashti Chaturthi is the Chaturthi, the fourth tithi, of the dark half of each lunar month, kept for Ganesha. It comes twelve times a year, thirteen in a year with an adhik month. Sankashti means release from hardship, and the tradition keeps it to ask Ganesha, the remover of obstacles, for help through difficult times. Each month's Sankashti worships a different form of Ganesha, named in the list on this page, and one that falls on a Tuesday is called Angaraki Sankashti and held in particular regard, above all in Maharashtra. The Sankashti of Kartik, in North Indian reckoning, is also Karwa Chauth.
02How the day and time are worked out
Sankashti is judged at moonrise, because the fast ends when the Moon is seen. The page lists it on the day whose moonrise falls inside the dark half Chaturthi, which sometimes puts it a day away from the date a calendar reading the tithi at sunrise would show. The time beside each entry is the moonrise for the city you choose, worked out for its own latitude and longitude. The Moon rises late on Krishna Chaturthi, well after sunset, and the hour differs from city to city by enough to matter, which is why no single national time is given here.
03How it is kept
The tradition keeps Sankashti with a fast from sunrise until moonrise. Ganesha is worshipped in the evening with durva grass, red flowers and modak or laddu, and the month's own form of Ganesha is named in the puja along with its katha. When the Moon rises, water, sandalwood and rice are offered to it, and only after seeing the moon is the fast broken, usually with the prasad. Families keep the fast at different strengths: some take nothing, others take fruit, milk, sabudana or peanuts during the day. A cloudy sky does not change the rule, and the moonrise time is followed.
04The rest of the calendar