This is a festival celebrating the birth of Lord Hanuman. Lord Hanuman was born on Chaitra-paurnima, the full moon day of the Hindu lunar calendar month of Chaitra. On this day, the Hanuman principle(tattva)is more active than on any other day of the year.In the states of Tamil Nadu and Kerala, Hanuman Jayanti is celebrated in the month of Margazhi( normally comes between Dec 15 to Jan 14 )as it is believed that Hanuman or Anjaneya was born on Moola Nakshatra,on the new moon day (amavasya) in the month of Margazhi. This is because, according to some religious almanacs (panchangs) the birthday of Lord Hanuman falls on the fourteenth day (chaturdashi) in the dark fortnight of the month of Ashvin while according to others it falls on the full moon day in the bright fortnight of Chaitra. 

On this day, spiritual discourses are started before dawn in Hanuman temples everywhere. The spiritual discourse ends at sunrise and prasad is distributed at the time, since Lord Hanuman was born at sunrise

Lord Hanuman
Lord Hanuman is the only deity who cannot be troubled by negative energies. He was born of the absolute air element (vayutattva). The well-known story that baby Hanuman leapt to devour the sun at birth, implies that the absolute air element (signified by Lord Hanuman in the story) is subtler and therefore, more powerful than the absolute fire element (tejtattva) signified by the sun in the story.

Hanuman's devotion and service unto Lord Rama was infinite and he was ready to sacrifice even His life for the sake of His Lord. Even the attainment of Liberation (Moksha) was worthless to Him. 

Idols of Lord Hanuman

Dakshinamukhi Maruti
Lord Hanuman facing south 
South refers to the direction south or the right side. This idol has more manifest energy and is worshipped to overcome any problems due to negative energy. 

Vamamukhi Maruti
Lord Hanuman facing the north 
North refers to the direction north or the left side. This idol has less manifest energy than the above and is worshipped to make spiritual progress. 

Dasmaruti
Lord Hanuman as the Servitor has Him standing before Lord Rama in obeisance. This statue emanates subtle vibrations of spiritual emotion (bhav). 

Viramaruti
His statue as the courageous one shows Him ready for battle. This statue emanates more positive energy and hence, is worshipped to overcome problems of negative energy, such as possession, black magic, etc.

Worship of Lord Hanuman
He is worshipped in the context of energy as follows.
To overcome distressing energy 
To overcome problems due to evil spirits, black magic, departed ancestors' subtle bodies, influence of the planet Saturn (Shani), etc.
To control pleasant energy
To overcome any obstacle in the pathway of the activated spiritual energy system (kundalini) and to channelize it appropriately, so that the seeker can continue his spiritual practice smoothly.

In Maharashtra Saturday is considered as an auspicious day for Lord Hanuman's worshipwhile in the rest of India, both Saturday and Tuesday are considered as auspicious days for His worship.On these days, vermilion and oil are offered unto Him. Vermilion and oil have the ability to attract the subtle pure particles of Lord Hanuman. Worshipping a spiritually charged image of a deity is obviously more beneficial in activating faith and spiritual emotion in the devotee.In some places coconuts are broken in front of Lord Hanuman’s image, as offering. Breaking of a coconut signifies the ’shattering’ of one’s ego and intellect at The Lord’s Feet.
Lord Hanuman’s worship yields protection from negative energies. Therefore on the days of His worship, especially people affected by negative energy worship Him by offering oil and vermilion. When one offers oil thus, one expels some negative energy that may be within one. 

PARTICIPATE IN THE HOMAM FOR HANUMAN