High in the Andes, on Cerro Tololo (2200m), sits a 4m telescope called the Blanco.  It was the first large telescope in the Southern Hemisphere, and from 1974 to 1998 was the largest telescope under the Southern Skies.  The Blanco was chosen as the telescope for the DECam imager because Cerro Tololo is a site with excellent observing conditions (an abundance of clear nights, stable atmospheric conditions and virtually no light pollution).

The DECam was delivered to the CTIO Blanco 4-m telescope in late 2011, commissioned in late 2012 and the DECam is now on the Blanco in full operation.  The entire camera with lenses, filters and CCDs weighs around 4 tons, and the Blanco structure required significant modifications to support this weight. 

The DECam resides in the prime focus of the Blanco, as shown below.

Left: The schematic view of the DECam, also showing the arrangement of the CCD array, optical lenses and filters.  Light enters from below in this diagram and passes through the corrector optics (not shown).  Middle:  The Blanco 4m telescope, with the red arrow designating where the DECam will be placed, on the prime focus.  Right: Four workers prepare the top end of the telescope for DECam installation.  The size of the people give a sense of scale of the photos.