Concentric Circles

In this eye-catching Picture of the Week, bright star trails fill the sky above ESO’s La Silla Observatory in Chile. Such trails are formed by the Earth spinning on its axis — our planet’s rotation causes the stars to seemingly move through the sky, slowly tracing out perfect concentric arcs and circles as they do so. A photograph like this therefore requires a long exposure to capture the passage of time.

At the centre of this image is the decommissioned Swedish-ESO Submillimetre Telescope , and the ESO 3.6-metre telescope sits atop the mountain to the left, aglow with activity. This telescope hosts HARPS (the High Accuracy Radial velocity Planet Searcher), which searches for exoplanets by measuring the tiny “wobbling” motions of their host stars as the planets sweep around in their orbits. 

Credit:

ESO/B. Tafreshi (twanight.org)

About the Image

Id:potw2041a
Type:Photographic
Release date:12 October 2020, 06:00
Size:6144 x 4096 px

About the Object

Name:ESO 3.6-metre telescope, Swedish–ESO Submillimetre Telescope
Type:Unspecified : Sky Phenomenon : Night Sky : Trail
Unspecified : Technology : Observatory : Telescope
Category:La Silla
Stars

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