No doubt King David compares the perfection of God's law to the glory of the heavens, but he did not learn that perfection from the heavens, but from the law itself, revealed in his own heart through the life-teaching of God.

When he had learned it he saw that the heavens were like it.
To unveil God, only manhood like our own will serve.

And he has taken the form of man that he might reveal the manhood in him from awful eternity..