Submillimeter Telescopes

The submillimeter band is a critical one for astronomy. It contains spectral and spatial information on very distant newly formed galaxies and on the early stages of star formation within gas clouds. Yet it is one of the few regions of the electromagnetic spectrum still to be made fully available to astronomy. This is in part due to the general difficulties of construction of detectors, receivers, and telescopes for these wavelengths and in part to the attenuating nature of the Earth's atmosphere. In recent years, optical style telescopes have become available, either on high mountain sites, or in the case of the NASA Kuiper Airborne Observatory (KAO) or Stratospheric Observatory for Infrared Astronomy (SOFIA) on board a high-altitude airplane. The James Clerk Maxwell telescope at 15 m and the Caltech Submillimeter Observatory (CSO) telescope at 10.4 m are both large enough to have developed the field. However, the ESA satellite Herschel has now provided the required space platform for complete spectral coverage and the Atacama Large Millimeter/Submillimeter Array (ALMA) the high spatial resolution, aperture synthesis, high-sensitivity platform.