The most important festival connected with Ganesha is the Vinayaka chathurthi. In this festival, Ganesha is invoked as the lord of the breath of life indicated by his name Vinayaka. This festival falls on the fourth day of the new moon in the month of Simha or Shravana (August-September). According to the Hindu Calendar each of the twelve divisions of the zodiac corresponds to a month each month being governed by its own tutelary planet. The month Simha is governed by the Sun the lord of our solar system. Esoterically Sun is symbol of the soul even in astrology and moon is the symbol of the mind.

When the moon in the course of its transit occupies any division where the sun also appears to be transitting the phenomenon of the New Moon appears. Esoterically this phenomenon is taken as the symbol of the merger of the mind with the soul. All desires of the mind are resolved in this blackout of perfect sunyam or emptiness. This state of sunyam is different from the state of nothingness. It is the state of absolute existence. It is not a negative notion. Dr. Jung calls this state as pleroma which is both full and empty. This state of existence is called in simple language as amohavasam (a life bereft of all desires). That is why the new moon is called amavasi which is a corruption of amohavasam. It is because of this esoteric significance orthodox Hindus consider amavasi as an auspicious day.

Amavasi state of mind is just like the mind of the foetus in the womb. Only after it comes out into the world it begins to express itself in terms of Manam (mind) Chith (Sub-conscious state), Buddhi (intellect) and Ahamkaram (ago). It is the ego the last stage of prana's manifestation that sustains the phenomenal world of relative values and it is this ego that is responsible for all the travails of life. This stage of ego is symbolised as the fourth day from Amavasi (New Moon) in the month of Simha and celebrated as Vinayaka chathurthi. Amavasi to Pournami (Full Moon) is a waxing cycle of the ego projected from the mind, culminating in pournami. In pournami, the sun and moon are in opposition. Though pourami has a halo of poetic fancy, it has an imperceptible power to excite and make people run berserk.