Obeisance to the Sun-God : makara sankrAnti

Pongal or Thai (தை) Pongal, the harvest festival, is also called makara sankrAnti, since it is celebrated on the first day of the tamizh month Thai(தை) when the Sun leaves the zodiac sign of Sagittarius and enters the Makara rAshi (Capricornus). (sankrAnti means transmigration of the Sun from one rAshi to the next). This signals the end of winter and the onset of spring throughout the northern hemisphere. For the next six months, the days are longer and warmer.

According to the calendar based on the solar system the year is divided into two halves following the apparent movement of the Sun northwards and Southwards. The former is termed uttarAyaNa and the latter is dakshiNAyaNa. 

This period of Thai (தை) is referred to as uttarAyaNa puNyakAla and is considered auspicious.

The four day celebration of Pongal marks a period of plenty, peace and happiness. There is a Tamizh saying "தை பிறந்தால் வழி பிறக்கும்", which means that, with the dawn of the month of Thai, there will be peace, happiness, prosperity, brightness and harmony in the life of everyone. (Another interpretation of this saying can be given as follows: after crops are harvested in the month of தை, the "varappu" (வரப்பு) or vazhi(வழி) for the farmers becomes visible.) It is held to honor the Sun, for a bountiful harvest. Families gather to rejoice and share their joy and their harvests with others.

Since this festival is essentially an obeisance to the Sun-God, I thought it would be apt to give in this post, the meaning to the beautiful kriti, sUryamUrtE (rAga saurAshtra), composed by Sri.Muthuswami Dikshitar, which is in praise of the Sun-God.
        

(पल्लवि)
सूर्यमूर्ते नमोऽस्तु ते
सुन्दर छायाधिपते

Hey Surya, Salutations to Thee ! , the one who is espoused to the beautiful chAyAdEvi.

(The choice of the word  नमोऽस्तु ते) in the first line looks very apt, since we always refer to sUryA as "namaskAra priyah" )

(अनुपल्लवि)
कार्य कारणात्मक जगत्प्रकाश
सिंह राश्यधिपते

One who is the cause(कारण) and effect (कार्य) of all things in Nature,  the One who enlightens the world(जगत्प्रकाश) and the adhipati of simha rAshi.

(मध्यम काल साहित्यम्)  
आर्य विनुत तेजःस्फूर्ते
आरोग्यादि फलद कीर्ते

One who is the personification of illumination, effulgence(तेजःस्फूर्ते) and worshipped by noble persons (आर्य विनुत).

sUrya namaskAr is one of the most effective methods to maintain good health and is a popular yogic exercise too (आरोग्यादि फलद कीर्ते)

(चरणम्)
सारस मित्र मित्र भानो
सहस्र किरण कर्ण सूनो
क्रूर पाप हर कृशानो
गुरुगुह मोदित स्वभानो
सूरि जनेडित सुदिनमणे
सोमादि ग्रह शिखामणे
धीरार्चित कर्म साक्षिणे
दिव्यतर सप्ताश्व रथिने

To You, the friend of the lotus(सारस मित्र), Hey MitrA (मित्र) !, Hey bhAnu (भानो)!
The One who is the source of a thousand brilliant rays (सहस्र किरण) and who is the father of karNA(कर्ण सूनो)
One who is the Fire (कृशानो) which can destroy even henious crimes (क्रूर पाप हर )
One who is self-effulgent (like the Pure Consciousness, citswarUpa brahman which is self-effulgent)
One who is worshipped by the Erudite (सूरि जनेडित) and One who is virtuous (सु) and the jewel of the day(दिनमणे)
One who controls the Moon and all the other planets (सोमादि ग्रह शिखामणे)
One who is worshipped by the Wise(धीरार्चित) and who is the witness to all Karma(कर्म साक्षिणे)
One who rides on a chariot driven by seven divine horses (दिव्यतर सप्ताश्व रथिने)

(मध्यम काल साहित्यम्)
सौराष्ट्रार्ण मन्त्रात्मने
सौवर्ण स्वरूपात्मने
भारतीश हरि हरात्मने
भुक्ति मुक्ति वितरणात्मने

Refers to the sUrya ashta akshara mantra and also the rAga mudra (सौराष्ट्रार्ण मन्त्रात्मने)
One who shines like gold, both in terms of mystical and intellectual brilliance (सौवर्ण स्वरूपात्मने)
One who is visualized as Brahma, Vishnu and Siva (भारतीश हरि हरात्मने)
One who instils devotion and imparts eternal bliss (भुक्ति मुक्ति वितरणात्मने)


Musical aspects of this kriti:

As per the sangIta sAmpradAya pradarshini, the rAga saurAshtrA is given under the 15th mElA mALavagowLa and not as a janya of chAyAvati (asampUrNa mELa equivalent of sUryakAntam, which is the way it is more commonly sung).

It is set to chatusra jAti dhruva tAlA, which has a 14-beat cycle and is one of the sULAdi sapta tALAs.