ISBN: | 978-5-5117-3598-6 |
High Quality Content by WIKIPEDIA articles! A pentaprism is a five-sided reflecting prism used to deviate a beam of light by 90°. The beam reflects inside the prism twice, allowing the transmission of an image through a right angle without inverting it (that is, without changing the image`s handedness) as an ordinary right-angle prism or mirror would.