Cleaning the Herschel primary mirror
Date: 14 February 2009
Depicts: Cleaning the Herschel primary with carbon dioxide snow
The Herschel primary mirror is cleaned using carbon dioxide snow (more commonly known as dry ice) which is produced by highly compressed liquid CO2 being expelled under high pressure. The snow particles vapourize upon hitting the surface of the mirror and in the process carry off any contaminants which may have been present. This technique is widely used also for ground -ased astronomical telescopes and has the major advantage of not requiring any physical contact with the optical surface. In this photograph the CO2 snow spray is clearly visible under reduced lighting conditions.
Last Update: 1 September 2019