Feature

Hubble: Looking for answers

R.R. Shannon

The Hubble Space Telescope consists of a large aperture diameter Cassegrain Telescope, called the Optical Telescope Assembly (OTA, for short, as NASA loves acronyms). This optical system feeds images to a variety of sensors that include cameras and spectrographs clustered about the focal plane of the OTA. The entire telescope assembly resides within a guidance and control spacecraft that uses information from optical sensors to provide the extremely fine pointing stability required for observation of faint objects. Since the telescope is in orbit, the optics should be nearly perfect to take maximum advantage of the absence of atmospheric limitations encountered by ground-based telescopes.