Mondays through Thursdays The Colbert Report was taped.
A Bauernfeind prism is a type of reflecting prism used to deviate a beam of light by 45 ° to 60 ° , depending on its construction , while neither flipping nor rotating the image .. prism. prism ( optics ). It is named for its inventor , the German expert of geodesy .. geodesy. geodesy. The beam is reflected twice in the prism , with one reflection happening at less than the critical angle , therefore the prism requires a reflective coating for this surface to be usable in practice .. prism. prism ( optics ). critical angle. total internal reflection. reflective coating. Mirror. A Bauernfeind prism with 45 ° beam deviation is also known as a half-penta prism or semipentaprism .. prism. prism ( optics ). A Bauernfeind prism is used together with a Schmidt roof prism to form a Schmidt -- Pechan prism .. prism. prism ( optics ). Schmidt roof prism. Schmidt roof prism