No ordinary camera, it captures light that has been stretched to higher wavelengths by the accelerating expansion of the universe. Apparently, cosmologists hope that studying this "redshifting" will reveal more about dark energy.
It consists of 74 CCDs and five lenses, biggest being almost 1 meter in diameter...
Jacob Aron writes:
DECam captures 570 megapixel images, about 100 times higher resolution than those taken by a typical smartphone, but the camera also has a wide view. A single image records an area of the sky 20 times larger than the moon as seen from Earth.
That's not the only difference between DECam and more down-to-earth snappers.
Cylindrical controls called hexapods, which you can see sitting roughly in the middle of the camera, constantly tweak the camera's focus to ensure a high image quality. The black box just to their left is a cartridge of swappable filters that let different wavelengths through.
Perhaps the only thing DECam can't do is upload its snaps to Facebook in a single click.
The science requirements of the Dark Energy Survey drive the construction of a brand new camera. Named DECam, this large, 570 Megapixel camera will hold 74 CCDs constructed specifically to be sensitive to the redshifted light from distant galaxies and stars. DECam will have the widest field of view in the NOAO ground-based optical/infrared system of imagers. Its 2.2 degree field of view is so large that a single image will record data from an area of the sky 20 times the size of the moon as seen from earth. This wide field of view requires that DECam use a system of five lenses, each one uniquely shaped to correct a variety of optical aberrations, with the biggest of these lenses being almost 1 meter in diameter.
See the camera being built: