Very large disk traveling east then north above the clouds, blocking out first a 3/4 moon and then stars as it traveled.The moon was blocked out to a sliver with a very sharp shape. As I observed the moon, thinking it was supposed to be about 3/4 from full, the disk began heading east with the clouds leaving the moon at it's appropriate size. As the disk (guessing at about 1000 ft in diameter) traveled above the clouds, it was going slower than the clouds, but it's shape was clearly visible through the clouds as a perfect disk and unlit. I realized what I was seeing was the shadow on the clouds from the moon. After about two minutes, it veered north and passed across some clear areas and appeared as a huge very black disk against a lighter sky and blocked out every star above it until it passed letting me once again see them. This took about 4-5 min., until it passed over a thick bodied cloud and was then gone from view.