Shuttle photograph of the moon setting over the earth's limb. The moon's image is distorted due to refraction through the Earth's atmosphere. A portion of the nearside of the moon is visible showing the vast area of the moon's Western Seas (Mare Occidental) and the large impact crater Copernicus. Scattering of sunlight from the Earth's upper atmosphere produces the halo of blue light. The semi-vortex in the clouds near the centre is probably a storm system in the early stages of formation.