It is a project to make a map of a large part of the night sky. The map will be very detailed and will allow scientists to find hundreds of millions of galaxies that have never been seen before. One of the primary purposes of the survey is to study how the Universe has changed over the last 14 billion years. The survey is being carried out from a mountaintop in Chile using a 4 metre telescope and the world’s largest digital camera.
The project is a collaborative effort of over 300 scientists from 25 institutions in 7 countries. We are using four different techniques to study Dark Energy: Supernovae, the spatial distribution of galaxies, Galaxy Clusters, and Weak Gravitational Lensing. The project started over 10 years ago. Once the camera, and other optical elements, had been built and shipped to Chile, DES started taking images of the sky, and has been doing so since August 2012. It will take until 2018 before all the data have been collected.