It's an expression of a Lunatic for it always amazes me how the moon appears to our eyes by every phase. "Lunatic" originally meant someone who went crazy with every phase of the moon, kind of like a werewolf. Most people these days don't believe in moon-caused insanity, but we still talk about lunatics, sometimes meaning clinically insane people. What can I say...I'm just totally amazed by it's beauty!