01What Ganesh Chaturthi is
Ganesh Chaturthi, or Vinayaka Chaturthi, is the fourth day of the bright half of Bhadrapada, kept as the birth of Ganesha, the remover of obstacles. It opens a festival of up to ten days that ends on Anant Chaturdashi, when the images are carried to water for visarjan. It is kept above all in Maharashtra, Goa, Karnataka and Andhra Pradesh, at home and in great public pandals.
02The story told of it
The Puranas tell that Parvati shaped Ganesha and set him to guard her door, and that Shiva, on his return, made him the leader of his ganas and gave him the right to be worshipped first in every rite. A second story explains the moon: when the Moon laughed at Ganesha on this day, Ganesha declared that whoever saw it on Chaturthi would bear a false blame, which is why the tradition asks people not to look at the moon tonight.
03How it is kept
A clay image of Ganesha is brought home and installed in the Madhyahna muhurat, the middle of the day, when the tradition places his birth. The puja calls him into the image with prana pratishtha and offers durva grass, red flowers, modak and laddoos, and the aarti is sung morning and evening. After one and a half, three, five, seven or ten days the image is taken in procession for visarjan in water.
04How the day is chosen
Ganesh Chaturthi is kept on the day Chaturthi covers Madhyahna, the middle fifth of the daylight, when the tradition places Ganesha's birth. The moon is not to be seen from when it rises during Chaturthi, or when Chaturthi begins if it is already up, until it sets.
05Ganesh Chaturthi in other years