Modern translations replace "excellent" with terms like "glorious," "great," or "majestic." The glory of God is revealed in His creation. One of His names, of course, is Creator. The psalmist sees the starry heavens stretched above him as an awesome and spectacular showcase of the majestic power of God.
The Soncino Commentary translates the second phrase of the first verse as, "Whose majesty is rehearsed above the heavens." The author comments, "The psalmist is saying that day after day man has the awesome splendor of God's power displayed before him." Thus, God has invested the heavens with glorious splendor to direct the mind of man to the Creator's majesty. This idea accepts that He is greater than even His creation demonstrates.
What excellence or glory do we see in the earth and sky? Do we consciously realize that a creator, any creator, is greater than what he creates, and do we then apply that inference to God? Do we see in it our holy Creator's power, order, beauty, loving providence, wisdom, reason, logic, and vastness of thought? Some measure of this will occur if we make the effort to seek Him.
God intends this psalm to direct our thinking toward His greatness and puny man's insignificance. Yet, that majestic, awesome God is glorifying Himself in man by creating in him the desire to be like Him! He has chosen what is weak and foolish—even by the world's standards—to appreciate and respect His glory, His name. Rightly understood, this is a truly humbling meditation.
John W. Ritenbaugh
The Third Commandment