Under the Southern Cross

This photo from the Ultra High Definition Expedition to ESO’s La Silla Observatory in Chile shows the Danish 1.54-metre telescope admiring the starry southern skies. The Southern Cross — one of the most distinctive asterisms — can be seen to the left of the telescope’s open dome, nestled in the plane of the Milky Way.

The constellation of Crux (The Cross) is best known for this cross-shaped asterism, which comprises four stars — Alpha, Beta, Gamma and Delta Crucis. The closest of these stars, Gamma,Crucis, sits just 88 light-years from Earth, while the furthest is 364 light-years away. The blue–white star Alpha Crucis, the bottom point of the Cross, is the 13th brightest star in the entire night sky.

The dark, inky smudge just above the Southern Cross is the Coalsack Nebula, one of the most prominent dark nebulae visible to the naked eye. This opaque cloud of interstellar dust obscures the light emitted by more distant stars, creating a seemingly starless void in the midst of the Milky Way. The fiery red emission nebula IC 2948 and distinctive Carina Nebula can be seen below the Cross as two patches of nebulosity.

The Southern Cross has great significance in the Southern Hemisphere. For centuries, it — like the Big Dipper in northern skies — served as a beacon for navigators because the longer bar of the Cross points almost exactly towards the south pole of the sky. The Cross has also played an important role in the spiritual beliefs of many southern cultures and it is also the logo of the European Southern Observatory.

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