Really long focal length and something called perspective compression. This image is an example for it: http://www.learnmyshot.com/photos/026-telephoto/026-telephoto_post3.jpg

See how the barn looks really big with a higher focal length and you only see a smaller portion of it? basically the same thing is happening with the moon. The people on the mountain are actually very far away and you only see a very small portion of the night sky, but it is also magnified. Because the moon is so big, of course it is also moving pretty fast.