Surya Dev occupies an important place in Vedic traditions. Pooja of Surya Dev with water in the morning, afternoon and evening is standard priestly tradition of Hinduism. Since he symbolizes Brahman himself, he is worshipped for the illumination of the mind and..
#Sunday

..flowering of self-knowledge.
Just as Brahman has triple aspects, namely Brahma, Vishnu and Shiva, Surya has triple aspects. In the morning, he is Brahma (golden yellow); in the afternoon, Maheshvara (bright white); and in the evening, Vishnu (dark blue).

He is the one wheeled chariot who travels in the sky and illumines the seven worlds.
According to the Vedas, the immortal world of Brahman is located in the sun. Liberated souls travel by the path of gods (devayana) and reach it from where they will never return.

If the sun is Brahman, the sun rays (rashmi) are the individual souls. The light from the sun is indestructible but it can be blocked by the clouds, just as the light from the soul is blocked by the impurities of consciousness. Om Surya Devaye Namah