Aditya Hrdayam is a devotional rendering for the worship of the Sun God. The video link below is of this wonderful hymn chanted by Swami Paramarthananda ji, of Arsha Vidya Gurukulam (AVG), who has rendered it in a most divine manner as well as perfectly in pronounciation and meter. It is such a pleasure to listen. The video has been uploaded by Prashant Parikh a brilliant young scholar of Vedanta from the AVG paramparaa.

Below is a brief introduction of this hymn as taken from Wikipedia.

[[ Ādityahṛdayam  is a devotional hymn associated with Aditya or the Sun God (Surya) and was recited by the Sage Agastya to Rāma on the battlefield before fighting the demon king Rāvana.

This historic hymn starts at the beginning of the duel between Rāma and Rāvana. Sage Agastya teaches Rāma, who is fatigued after the long battle, the procedure of worshiping the Sun God for strength to defeat the enemy. These verses belong to Yuddha Kānda (Book 6) Canto 107, in the Rāmāyana as composed by Agastya and compiled by Vālmīki.]]

Pranaam from Kamal Kothari