as glass to reduce the number of parts that would be required additional elements to support the fiber and provide strain relief would generally be beneficial referring now to fig4 and 5 the optical delivery system and optical collection system preferably are constructed based on a pentaprism according to normal convention and as shown in fig4 the pentaprism typically has five sides however it should be noted that the shortest of the five sides of a typical pentaprism often has no optical function and may be eliminated by extending the two adjacent sides until they intersect designs based on a pentaprism may also include additional sides in excess of five as shown for example in the exemplary designs of fig4 and 5 due to the manufacture of the prism from separately made parts it should also be understood that although a pentaprism is used in the preferred embodiment other prisms or optical designs may be used as indicated by the optical design depicted in fig3 the pentaprism provides for a more compact design while allowing a longer optical path between the fiber optic or fiber optics and the focusing surface which in turn makes certain conjugate ratio optical systems more practical pentaprisms also offer reflection angles that are much closer to perpendicular and are therefore especially.