APOD 3.1

"Full Moon" takes you to a site on the moon phases.
"twenty Full Moons" takes you to a site where you can buy a poster of the picture above.
"lunation" takes you to an APOD animation entitled "Lunation."
"same scale" takes you to an APOD entitled "Moon Over Andromeda."
"Moon Illusion" takes you to an APOD entitled "Moonrise Over Seattle."
"the variation" takes you to a site that explains why the moon is different sizes.
"libration" takes you to a site that explains the libration of the moon. It explains why astronomers can see a little more than half the moon's surface thanks to this process.
"twenty frame movie" takes you to a site that goes through each of the boxes above in their own frame as a movie.