The Atacama Cosmology Telescope - ACT

The Atacama cosmology telescope (ACT) is a new, 6-meter aperture, millimeter-wave telescope that is located at an altitude of 5200 meters in the Chilean Andes. ACT will be fielded with the millimeter bolometric array camera (MBAC). The MBAC incorporates arrays of "pop-up" bolometers using multiplexed transition edge sensors (TES), developed at NASA/GSFC and NIST. The camera will consist of three arrays for multi-frequency ground-based millimeter observations near 150, 220 and 270 GHz. The goal is to map the cosmic microwave background and discover Sunyaev-Zel'dovich clusters. Associated follow-up observations of the clusters will be taken at optical and X-ray wavelengths. The ACT telescope had first light with a the CCAM test receiver in June of 2007. The installation of MBAC with a 1000 elemet array at 150 GHz is expected in October of 2007. All three arrays will be installed in June of 2008.