The submillimeter band is that part of the electromagnetic spectrum lying between the far infrared and microwave region, corresponding to wavelengths between about 300 microns and 1 mm. The submillimeter band is particularly important in astronomy for making observations of objects which are are useful for finding out more about the early universe. Most of this astronomically important radiation is blocked by Earth's atmosphere, so to combat this problem instruments must be placed on the ground at high altitude or in space.
Submillimeter wave astronomy
Submillimeter wave astronomy is the study of the universe in the last waveband of the electromagnetic spectrum to be explored from Earth: the submillimeter window. This bandwidth in this window is ideally suited for studies of the structure and motions of the matter that forms stars; of the spiral structure of galaxies, as outlined by their giant molecular clouds; and of quasars and active galactic nuclei. The submillimeter window lies between the longest infrared wavelengths and the short radio waves in the millimeter band.
Caltech Submillimeter Observatory
The Caltech Submillimeter Observatory (CSO) is a 10.4-m-wide radio dish, of hexagonally-segmented design, located near the summit of Mauna Kea, Hawaii, and operated by the California Institute for Technology. One of the most advanced instruments for submillimeter astronomy, it also the world's only professional observatory without an operator: the astronomer, while observing, is given full control of the telescope.
The Submillimeter Array is radio interferometer consisting of an array of eight movable reflectors, each 6 m in diameter, located near the summit of Mauna Kea, Hawaii It can cosmic sources at high resolution in the submiliimeter band between frequencies of 180 GHz to 420 GHz. The Submillimeter Array is a joint project between the Smithsonian Astrophysical Observatory and the Academia Sinica Institute of Astronomy and Astrophysics, Taiwan.
Submillimeter Telescope Observatory
The Submillimeter Telescope Observatory (SMTO) is an observatory at an altitude of 3,180 m on Emerald Peak of Mount Graham, about 120 km northeast of Tucson, Arizona. It houses the Heinrich Hertz Telescope, a 10-m dish for use at submillimeter wavelengths that was opened in 1994. SMTO is jointly owned and operated by the Max-Planck-Institut für Radioastronomie (Bonn) and the University of Arizona's Steward Observatory.