Bhagavad Gita, Chapter 10, Verse 21

Of the Adityas, I am Vishnu; of luminaries, the radiant Sun; of the winds, I am Marichi; of the asterisms, the Moon.

The brightest, most necessary things in the sky are each named here as a real reflection of the same source.

Choosing the sun and the moon isn't random, both are described as what actually makes darkness or confusion recede. Real necessity, not just brilliance, is what earns these examples their place.