The Chaturthi after Amavasya or new moon during Shukla Paksha is known as Vinayaka Chaturthi. Naga Chaturthi falling on the 4th day during the bright fortnight of auspicious Sravana Maasa followed by Naga Panchami on the next day is celebrated as Naga Devatha festival.
Each lunar month in Hindu calendar has two Chaturthi Tithis. According to Hindu scriptures Chaturthi Tithi(s) belongs to Lord Ganesha.
The Chaturthi after Amavasya or new moon during Shukla Paksha is known as Vinayaka Chaturthi.
The Chaturthi after Purnimasi or full moon during Krishna Paksha is known as Sankashti Chaturthi
Though Vinayaka Chaturthi fasting is done every month but the most important Vinayaka Chaturthi falls in month of Bhadrapada. It is widely known as Ganesh Chaturthi. Vinayaka Chaturthi is also recognized as ‘Varad Vinayaka Chaturthi’. The word Varad means ‘boon’. Those who keep fast on this auspicious day are showered with power and intelligence by the Almighty. Ganesha Puja on Vinayaka Chaturthi is done during afternoon which is midday according to Hindu calendar.
After early morning bath, prayers are offered to Lord Ganesha in the usual way by lighting a lamp or Aarti. After performing this the fast begins. Then in the evening the puja is usually performed after sighting the moon or as per the moonrise time given in the panchang or calendar (if the moon is not visible for a long time). After sighting the moon, murthy (idol) or painting or photo of Lord Ganesha is decorated using flowers and Durva grass and a lamp is lit. A coconut, banana, prasad (Modak) and flowers are offered to Lord Ganesha. Then the evening aarti is performed and Ganpati mantras are chanted. Special pujas are offered to Chandra or moon god. The puja involves sprinkling water, sandalwood paste, flowers and consecrated rice in the direction of the moon. After the puja the prasad and the other offering to the lord are distributed.