The twin pillars of the Milky Way

This striking UHD panorama shows a bizarre-looking scene at ESO’s Paranal Observatory, home to ESO’s Very Large Telescope (VLT). The Milky Way graces the skies above the observing site every single night, and is visible in stunning detail and clarity. But here, the galaxy appears to dip down through the night sky and create two separate columns, while still filling the sky towards the top of the frame. Why is this view so distorted?

The sculpting and reshaping of this familiar celestial scene result from the way in which the photographer, ESO Photo Ambassador Petr Horálek, captured the image. Horálek photographed the entire dome of the sky, from zenith to horizon, a full 360 degrees around. The “two Milky Ways” are in fact a single band — the plane of our galaxy as it arcs across the sky from horizon to horizon. As it passes overhead, it appears to spread out across the top edge of the panorama due to the distortion needed to squeeze the full dome of the sky into a flat, rectangular image.

Although the Milky Way steals the show, many other notable celestial objects are visible here. The blueish spot between the two leftmost telescope domes (one of which is blurred because it was moving at the time!) is the Pleiades star cluster. Above the Pleiades sit the Orion Nebula, Barnard’s Loop, and the pink Rosette Nebula. At the centre of the image, Jupiter stands out brightly. The orange glow just below Jupiter is produced by an optical phenomenon known as airglow, which is often seen in extremely dry atmospheric conditions such as those found at Paranal (in the Chilean Atacama Desert). Captured within the rising, smoke-like chimney of the Milky Way on the right are the Gum Nebula, Carina Nebula, and the dark Coalsack Nebula— and the two Magellanic Clouds are visible as bright smudges towards the right edge of the frame.