Bhogi, Makara Sankranthi, Kanuma and Mukkanuma are celebrated as biggest and one of the auspicious festivals in Andhra Pradesh. In fact, celebrations of this festival begins a month before and that is called Dhanur Masam.
Bhogi is the first day of this four day pongal festival. Normally it comes on 13th day of January; but sometimes it would come on 14th day of January too.
About Bhogi from Wikipedia:
On Bhogi, people discard old and derelict things and concentrate on new things causing change or transformation. At dawn, people light a bonfire with logs of wood, other solid-fuels and wooden furniture at home that are no longer useful. The disposal of derelict things is where all old habits, vices, attachment to relations and material things are sacrificed in the sacrificial fire of the knowledge of Rudra, known as the “Rudra Gita Jnana Yajna”. It represents realisation, transformation and purification of the soul by imbibing and inculcating various divine virtues. Bhogi is celebrated the day preceding Thai Pongal, Makar Sankranti and Lohri.
During my childhood, it used to be one of the festivals we wait for (even now in villages); On Bhogi day, we get up early, get ready and go to bonfire place; then we used to walk through the village to enjoy seeing rangoli. Each house use to make an innovative design of rangoli.
Second day of the festival is Makara Sankranti; this is the day where we can witness divine light up hill of Sabari Malai.
About Makara Sankranti from Wikipedia:
Makar Sankranti also known as Makara Sankranti marks the transition of the sun into the zodiacal sign of Makara (Capricorn) on its celestial path, which is the first change in the zodiac after the winter solstice and is the first day of the month of Magha. The festival is celebrated in various parts of the Indian subcontinent to observe the day which marks the shift of the sun into ever-lengthening days. The festival is a seasonal observance as well as a religious celebration. Makara Sankranthi is a solar event making it one of the few Hindu festivals which fall on the same date in local calendars every year: 14 January, with some exceptions when the festival is celebrated on 15 January
This is one festival where most families get together and celebrate together. A very auspecious and special festivals for new couples.
Wishing you all a happy Pongal!