OPTICS & OPTICAL PHENOMENA TELESCOPE EQUIPMENT A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z                    HOME ABOUT CATEGORIES SITE MAP COPYRIGHT ADVERTISE CONTACT entire Web this site Nasmyth focus The Nasmyth foci of the Subaru Telescope A focal point to one side of the tube of a telescope with an altazimuth mount. It is formed by placing a third mirror (tertiary) so as to direct the beam along the altitude axis and through a hole in the supporting trunnions. Nasmyth foci enable bulky instruments to be mounted on a permanent platform that needs to rotate only in azimuth; they are commonly used with large modern telescopes, especially for spectrographic work. Named after the Scottish engineer James Nasmyth (1808-1890), best known for his invention of the steam hammer. Related categories    • OPTICS AND OPTICAL PHENOMENA    • TELESCOPE EQUIPMENT AND TECHNIQUES Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP