SUN PILLAR Taken by Miguel Claro on October 16, 2015 @ Paranal, Atacama desert, Chile.

After the sunset, in the beginning of twilight, a partial cloudy sky can promote an impressive combination of beautiful colors. Sometimes, we can see a phenomenon called Sun Pillar. A sun pillar is a vertical shaft of light extending upward from the sun. This great moment was captured in Cerro Paranal, where stands the VLT Telescope.
The Very Large Telescope (VLT) is a telescope operated by the ESO – European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile. The VLT is the world’s most advanced optical instrument, consisting of four Unit Telescopes with main mirrors of 8.2m diameter, which are generally used separately but can be used together to achieve very high angular resolution. The four separate optical telescopes are known as Antu, Kueyen, Melipal and Yepun, which are all words for astronomical objects in the Mapuche language, with optical elements that can combine them into an astronomical interferometer (VLTI), which is used to resolve small objects. The interferometer is complemented by four movable Auxiliary Telescopes (ATs) of 1.8 m aperture. The 8.2m diameter Unit Telescopes can also be used individually. With one such telescope, images of celestial objects as faint as magnitude 30 can be obtained in a one-hour exposure. This corresponds to seeing objects that are four billion (four thousand million) times fainter than what can be seen with the unaided eye. The telescopes can work together, to form a giant ‘interferometer’, the ESO Very Large Telescope Interferometer, allowing astronomers to see details up to 25 times finer than with the individual telescopes. The light beams are combined in the VLTI using a complex system of mirrors in underground tunnels where the light paths must be kept equal to distances less than 1/1000 mm over a hundred metres. With this kind of precision the VLTI can reconstruct images with an angular resolution of milliarcseconds, equivalent to distinguishing the two headlights of a car at the distance of the Moon.

Image taken taken in 16/10/2015 from Cerro Paranal, Atacama desert, Chile.