Worship of the Sun

The Sun is stated be none other than Mahavishnu Himself. He is the God manifest before our eyes. He is known as Aditya , the son of Aditi.
Who is the son of Aditi ? Vamana is the son of Aditi who is an avatar of Mahavishnu.
So the Sun is indeed MahaVishnu Himself. That is why we worship the early morning Sun as Vamana. Worshipping the morning Sun gets rid of our lethargy and laziness and fills us with energy. Azhvars have extolled the Vamana avatara. Andal celebrates this avatara of the Lord , where He grew in size and measured the worlds. Tiruvalluvar in kural 610 says a king should be like Vamana in conquering the three worlds.
The Sun is the most important among the nine planets around Whom the celestial beings namely the Devas and other planets revolve. It is important to note that the Sun is remembered through prayers in the morning and evening. In the evening the Sun is worshipped as Varuna - the rain God which is his manifestation.
Mahabaratha shows the conversation between Yama in guise of a Yaksha ( good fairy) questioning Yudhishtra about the Sun.
Yaksha asks " Who makes the Sun rise" for which Yudishtra replied that is the Brahmam- the Supreme One and "Who makes the Sun set" for for which Yudishtra replied that is the dharma which makes the Sun set. Therefore the Sun is anchored in Truth. ( It is to remember Mahatma Gandhi s famous line "Truth is God" )
Yaksha also poses another question - " what is a daily occurrence ? "
Yudhishtra replies that the illusory world may be seen as a vessel , covered with the sky as a lid. Day and night are the firewood and the fire that lights this firewood is the Sun. Months and Seasons constitute the ladle , Time stirs the contents in the vessel which include all the movable and immovable things and this is a daily occurence.
Reference from : " The Hindu " newspaper and internet sources