The European Southern Observatory (ESO) used a 2.2-metre telescope at the La Silla Observatory in Chile to take this image of thousands of galaxies. They used a wide-field shot, which covers an area of the sky that is approximately the size of a full moon. In some of the galaxies, one can discern the spiral arms or elliptical halos. These galaxies are thought to be closer to Earth. Some of the galaxies are indistinct blobs. These galaxies are thought to be farther away from Earth.
Beginning in the centre of the image and extending below and to the left, a concentration of about a hundred yellowish galaxies identifies a massive galaxy cluster, designated with the number 315 in the catalogue compiled by the American astronomer George Abell in 1958 [1]. The cluster is located between the faint, red and blue galaxies and the Earth, about two billion light-years away from us. It lies in the constellation of Cetus (the Whale).
and what about those red, green, and blue streaks?
The blue, green or red tracks indicate that each asteroid has been detected through one of the three filters, respectively. Each track is composed of several, smaller sub-tracks, reflecting the sequence of several exposures performed in each of the filters; from the length of these sub-tracks, the distance to the asteroid can be calculated.
