Telescope mirror manufacture. Manufacture of the mirror destined for use in one of the two Gemini telescopes. The polishing machine (white, centre left) uses circular scrubbing patterns to smooth the mirror's surface to within one micrometre. This 8-metre diameter mirror is only 20 centimetres thick. The twin Gemini telescopes, each with a single mirror, are being built at Mauna Kea, Hawaii, and Cerro Pachon, Chile. They will be used for optical and infrared observations. The Mauna Kea telescope is expected to be completed by the end of 1998. Photographed in 1997 at the REOSC workshops in Melun, France.