Western Moon, Eastern Sea

Explanation: The Mare Orientale,Latin for Eastern Sea, is one of the most strikinglarge scale lunar features. The youngest of the large lunar impact basins it's very difficult to see from anearthbound perspective. Still, taken during a period of favorable tilt, or libration of the lunarnearside, the Eastern Sea can be found near top center in this sharptelescopic view, extremely foreshortenedalong the Moon's western edge. Formed by the impact of an asteroid over 3 billion yearsago and nearly 1000 kilometers across, theimpact basin'sconcentric circular features are ripples in the lunar crust. But they are a little easier to spot inmore direct images of the region taken fromlunar orbit. So why is the Eastern Sea at the Moon's western edge? The Mare Orientale lunar feature was named before 1961. That's when the convention labelingeast and west on lunar mapswas reversed.

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Explanation: Named for the southern constellationtoward which most of its galaxies can be found, theFornaxCluster is one of the closest clusters of galaxies. About 62 million light-years away, it is almost 20 times moredistant than our neighboringAndromeda Galaxy, andonly about 10 percent farther than the better known and morepopulated Virgo Galaxy Cluster. Seen across this two degree wide field-of-view, almost everyyellowish splotch on the image is an elliptical galaxy in the Fornaxcluster. Elliptical galaxiesNGC 1399 and NGC 1404are the dominant, bright cluster members toward the upper left(but not the spiky foreground stars). A standout barred spiral galaxyNGC 1365is visible on the lower right as a prominent Fornax cluster member.