Throughout this verse, David reminds us that God created all the heavens and put the moon and stars into orbit as a result of the work of His fingers. Looking up at the stars on a clear, starry night helps us gain a deeper understanding of God's majesty, wisdom, and power. It is true that many pagan religions worship the sun, moon, and stars, but their focus is not well placed. Rather than focusing on the heavenly bodies, we should concentrate on the One who created them.
Even though the Lord set the sun and moon in place to govern the day and the night, it was a man who was created in God's image who was appointed to lead the earth as God's appointed representative. In the beginning, God created man to be ruler over all the fish of the sea, all the fowl of the air, all the cattle, and all the creeping things that inhabit the earth.
The only creature created in the image and likeness of God to rule and reign on the earth as a regent under the supreme authority of God was man. Thus, it is no surprise that the psalmist begins and concludes his hymn of praise to his Creator with the words: how excellent is thy name in all the earth!

Dear Heavenly Father, the magnificence of the extended universe overwhelms me when I consider man's insignificance. However, You loved me so much that You gave Your only begotten Son to pay for my sins. In gratitude for this, I give You all the praise and glory in the world. I am reminded that I was created for a divine purpose: to be the means by which the invisible God could be made visible to His creation. 
In Jesus's name I pray. Amen.