In the vedic culture the Gods of nature are worshipped, like Vasus (deity of elements: agni, jal, vayu and more), rudra, ashwini kumar and Aditya. Aditya means the son of devi aditi and this stotra pleases the Lord's heart and hence called Aditya Hrudayam Stotram. In hinduism or any other culture sages always worship the Lord Sun as the presiding deity. In one of the oldest text, vedas (Rigveda) the mantras and stotras are there to worship the Surya Dev. This blog gives aditya hrudayam stotra is sanskrit and english with meaning and explanation.
Karma yoga is the union with God by doing. We can say it is "Yoga of Action". But what actions and how they need to be performed. In this context, the principle of Karma Yoga described in the Gita is most acceptable. Bhagavad Gita says that doing nishkama karma, the karma with non attachment, non desire, non intention is the way to attain yoga. What Lord Krishna says more on this, lets see.