The Advanced Camera for surveys

The Advanced Camera for. Surveys (ACS) is a third generation instrument for the Hubble Space Telescope (HST). It is currently planned for installation in HST during the fourth servicing mission in Summer 2001. The ACS will has three cameras. The first, the Wide Field Camera (WFC) is a high-throughput (-42% at 600 nm, including the HST OTA), wide field imaging camera optimized for the near-IR. WFC has a 202 x 202 field of view with a plate scale of 0.05/pixel, delivered by a mosaic of two 2048 x 4096 CCDs. The WFC is designed to achieve a factor of 10 increase in discovery efficiency at 800 nm, where discovery efficiency is defined as the product of field of view and instrument throughput. The second, the High Resolution Camera (HRC) is a near-UV optimized camera designed for critically sampled imaging in the visible, with the capability for high contrast, coronographic imaging. The HRC has a field of view of 26 x 29 with a plate scale of 0.027/pixel. The third camera is the Solar Blind Camera (SBC), which is optimized for far-UV imaging. The SBC has a field of view of 31 x 35 with a plate scale of 0.032/pixel. The ACS science team will employ -60% of the dedicated GTO time to conducting a WFC deep survey of clusters of galaxies at intermediate redshift, mapping the large scale distribution of dark matter around low redshift clusters, and studying the nature of galaxies at z>4. HRC observations of a sample of early galaxies will be surveyed for nuclear disks, and combined with spectroscopic observations to measure central masses and determine if black holes are present. A novel polarimetric technique will be used to measure geometric distances to galaxies and provide an independent measure of Ho. The HRC coronograph will be used to conduct studies of dust disl around nearby stars and to search for planets.