APOD: 2022 January 27

Explanation: South of the large star-forming region known as theOrion Nebula, lies bright blue reflection nebulaNGC 1999. At the edge of theOrion molecularcloud complex some 1,500 light-years distant, NGC 1999'sillumination is provided by the embedded variable star V380 Orionis. The nebula is marked with a dark sideways T-shape at center right inthis telescopic vistathat spans about two full moons on the sky. Its dark shape was once assumed tobe an obscuring dust cloud seen in silhouette. But infrared datasuggest the shape is likely a hole blown through the nebulaitself by energetic young stars. In fact,this region aboundswith energetic young starsproducing jets and outflows with luminous shock waves. Cataloged as Herbig-Haro (HH) objects, named for astronomersGeorge Herbig and Guillermo Haro,the shocks have intense reddish hues. HH1 and HH2 are just below and right of NGC 1999. HH222, also known as theWaterfall nebula,looks like a red gash near top right in the frame. To create the shocks stellar jets push throughthe surrounding material at speeds ofhundreds of kilometers per second.

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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, ripples in the lunar crust,are a little easier to spot inspacecraft images of the Moon, though. 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.