The Dark Energy Survey will conduct a five-year census of galaxies and stars over a full eighth of the night sky in an effort to understand what is driving the accelerating expansion of the cosmos. The survey will be carried out by the 570-megapixel Dark Energy Camera, photographed here in its black housing on the Victor M. Blanco Telescope in Chile. Josh Frieman's article on page 28 describes the science underlying the survey and some of the camera's advanced technology.

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Goal of the Supernova hubHigh redshift observations of Type Ia Supernovae (SN) provided the first convincing evidence for the existence of Dark Energy (DE). These observations remain one of the most useful tools for constraining cosmological parameters. Despite numerous advances in observational and theoretical techniques towards understanding Type Ia SN, there remain many potential systematic uncertainties that can limit the cosmological precision obtainable from SN surveys. These systematic uncertainties have become the limiting factor in SN constraints on DE. It is the goal of the Supernova Hub to carry out a research program to understand and reduce these potential systematic errors, thereby improving SN as cosmological probes.