It is enchanting, spectacular and - at 3.5m in diameter - it will soon become the biggest telescope mirror in space, surpassing that of Hubble.... It will take up a vantage point a million-and-a-half kilometres from Earth, to open up what scientists expect to be an utterly fascinating new vista on the Universe. Unlike Hubble, which is tuned to see the cosmos in the same light that is visible to our eyes, Herschel will go after much longer wavelength radiation - in the far-infrared and sub-millimetre range. It will permit Herschel to see past the dust that scatters Hubble's visible wavelengths, and to gaze at really cold places and objects in the Universe - from the birthing clouds of new stars to the icy comets that live far out in the Solar System.... Some of these targets, though, are frigid in the extreme (between five and 50K); and for Herschel to register them requires an even colder state be achieved on the observatory itself. This involves the use of a cryostat.
astronomy universe Herschel Planck ESA telescope space