The sky as a natural metaphor for the mind is used in the sacred poetry of the East, especially in Buddhist traditions. When the sky is clear, still, empty, open, we can perceive the sources of heavenly light -- the sun, moon, and stars. But when the sky is clouded and turbulent, the heavens are hidden and the world below becomes dark.
In deep peace, when the mind is undisturbed by internal chatter and other tremors, perception is no longer obscured and awareness of the Divine shines through. In fact, what we call "mind" ceases to exist when it is still; it settles into a vibrant emptiness. It is as if the sky vanishes when the clouds disappear and we are left with only the experience of sunlight shining everywhere.