Captured last April after sunset on a Chilean autumn night an exceptionally intense airglow flooded this scene. The panoramic skyscape is also filled with stars, clusters, and nebulae along the southern Milky Way including the Large and Small Magellanic clouds. Originating at an altitude similar to aurorae, the luminous airglow is due to chemiluminescence, the production of light through chemical excitation. Commonly recorded with a greenish tinge by sensitive digital cameras, both red and green airglow emission here is predominately from atmospheric oxygen atoms at extremely low densities and has often been present in southern hemisphere nights during the last few years. Like the Milky Way on that dark night the strong airglow was visible to the eye, but seen without color. Mars, Saturn, and bright star Antares in Scorpius form the celestial triangle anchoring the scene on the left. The road leads toward the 2,600 meter high mountain Cerro Paranal and the European Southern Observatory’s Very Large Telescopes.
An example of violence on a cosmic scale, enormous elliptical galaxy NGC 1316 lies about 75 million light-years away toward Fornax, the southern constellation of the Furnace. Investigating the startling sight, astronomers suspect the giant galaxy of colliding with smaller neighbor NGC 1317 seen just above, causing far flung loops and shells of stars. Light from their close encounter would have reached Earth some 100 million years ago. In the deep, sharp image, the central regions of NGC 1316 and NGC 1317 appear separated by over 100,000 light-years. Complex dust lanes visible within also indicate that NGC 1316 is itself the result of a merger of galaxies in the distant past. Found on the outskirts of the Fornax galaxy cluster, NGC 1316 is known as Fornax A. One of the visually brightest of the Fornax cluster galaxies it is one of the strongest and largest radio sources with radio emission extending well beyond this telescopic field-of-view, over several degrees on the sky.