Amici roof prism

The Amici prism ( after its inventor Giovanni Battista Amici ) is a belonging to the inverting prisms optical prism. It is used in optical systems to angle a beam path by 45 ° or 90 °, thereby causing no swapping two opposite sides, or not to make the image reversed.

It is named after Amici because it as reflecting surfaces has only two roof prism surfaces and roof prism. In his short term roof prism it represents the basic form of all complex inverting prisms which also contain roof prism surfaces, dar.

Design and operation

The Amici prism is an ordinary prism in half cube shape ( right-angled triangle as the base ) with one on the long side ( hypotenuse ) patch " roof edge ", ie, with two patch mutually perpendicular faces.

In roof prism part of the image in the middle is cleaved, and the fields are each twice reflected separately before they recombine. This needs with high accuracy - accurate to about 3 to 4 seconds of arc - happen, otherwise double images arise. The necessary precision generally more expensive production of the Amici prism. In the automatic production nowadays used but the difference is barely present.

Roof pages are used in numerous other prisms for image change, this includes the roof prism and penta -, the Schmidt- Pechan, the Abbe-Koenig and Uppendahl prism.

Application and similar prisms

Amici prism are used for example in the angled finder of a telescope and is thus among other things, in observational astronomy frequent use. The advantage here is that through the upright and correct position of the objects when the telescope orientation is easier, since the direction of movement of the instrument and the observed shift in the eyepiece are the same.

Prisms, which are used for similar purposes, are the Roof pentaprism, which is particularly common in cameras, and the double Porro prism that is often built into binoculars.

Amici prism with 45 ° deflection and 1.25 " Steckmaß

• Reflection prism
• Optical Telescope Technology