STS080-759-038 (19 Nov.-7 Dec. 1996) --- As photographed by the crewmembers aboard the space shuttle Columbia, a full moon is about to set beyond the limb of Earth. A full moon should be round but when it is near the limb, or edge of Earth, the atmosphere tends to distort the shape. The atmosphere, stratosphere, ionosphere is in reality acting as a lens, thus the distorted shape of the Moon. As the Moon reaches the Earth's horizon it will become "eggshaped".