Atacama Cosmology Telescope

The Atacama Cosmology Telescope is a six-meter diameter telescope located on Cerro Toco in the Atacama Desert in the north of Chile, near the Llano de Chajnantor Observatory. ACT makes high-sensitivity, high-resolution, microwave-wavelength surveys of the sky in order to study the cosmic microwave background radiation, the relic radiation left by the Big Bang process. At an altitude of 5,190 metres, it is one of the highest permanent, ground-based telescopes in the world.High sensitivity observations of the cosmic microwave background radiation allow precision measurements of cosmological parameters, detection of galaxy clusters among other scientific goals, probing the early and late stages in the history of the evolution of the universe.

Erected in the autumn of 2007, ACT saw first light on 22 October 2007 with its science receiver, the Millimeter Bolometer Array Camera. ACT has had two major receiver upgrades which enabled polarization sensitive observations: ACTPol and Advanced ACT.