| opt. |
Doppelprisma n (internally reflecting prism used to turn a beam of light through precisely 90° or 180°); Prismeninstrument n (internally reflecting prism used to turn a beam of light through precisely 90° or 180°); Prismenkreuz n (internally reflecting prism used to turn a beam of light through precisely 90° or 180°); Spiegelinstrument n (in which two mirrors turn a beam of light exactly through a right angle); Winkelinstrument n (in which two mirrors turn a beam of light exactly through a right angle); Winkelprisma n (surveying: internally reflecting prism used to turn a beam of light through precisely 90° or 180°) |
