Hubble Space Telescope, primary mirror, 1981-82.
#1. Workers study Hubble’s main, eight-foot (2.4 m) mirror.
#2. Engineers inspecting the Hubble Space Telescope’s (HST’s) Primary Mirror at the Perkin-Elmer Corporation’s large optics fabrication facility. After the 8-foot diameter mirror was ground to shape and polished, the glass surface was coated with a reflective layer of aluminum and a protective layer of magnesium fluoride, 0.1- and 0.025- micrometers thick, respectively.
#3. Prior to installation, technicians inspect the primary mirror of the Hubble Space Telescope (HST).
The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth orbit. By placing the telescope in space, astronomers are able to collect data that is free of the Earth’s atmosphere. The Marshall Space Flight Center had responsibility for design, development, and construction of the HST and the Perkin-Elmer Corporation, in Danbury, Cornecticut, developed the optical system and guidance sensors.
Hubble, like all telescopes, plays a kind of pinball game with light to force it to go where scientists need it to go. When light enters Hubble, it reflects off the main mirror and strikes a second, smaller mirror. The light bounces back again, this time through a two-foot (0.6 m) hole in the center of the main mirror, beyond which Hubble’s science instruments wait to capture it. In this photo, the hole is covered up.