9512594 Stubbs Silicon technology has revolutionized astronomy by giving us near perfect CCD light detectors that have very high quantum efficiency and linearity compared to the old standard: photographic plates. However, individual CCD detectors are very small compared to photographic plates and cover only a small amount of sky so that most of the light gathered by the telescope mirror is wasted. This program will develop a powerful wide-field CCD camera system for the Apache Point Observatory (APO) 3.5 meter telescope that will be as large as any yet built (67 million pixels), and will have state-of- the-art read-outs and data processing capability. This versatile instrument will make possible a wide range of astrophysical observing programs, particularly those that attack pressing open questions in observational cosmology such as: How fast is the universe expanding?; Will this expansion continue forever?; what is the nature and distribution of the dark matter that is the gravitationally dominant component of the universe?; and What is the role of particle physics in the birth and evolution of the universe? ***
