35mm adapters - image correction using Schmidt Prisms at DVinfo.net

Simon Fenton · June 16th, 2004, 08:28 AM

thought I'd share this info that I found.

An Amici prism is much like a prism star diagonal, except that its hypotenuse, rather than being flat, is
ground into 2 faces forming a 90 degree roof. A light ray from the telescope enters the front face nearly
flat-on, bounces off one face of the roof, then bounces off the other face of the roof, then exits the top
face. The Amici prism diverts the beam by 90 degrees while turning it right side up and correct
left-to-right.

A Schmidt prism (which many people have been incorrectly calling Amici) turns the beam through 45 degrees
while turning it right side up and correcting it left-to-right. Conceptually, take an Amici prism and deform
it by pushing its top face down to the 45 degree angle, while the ridge of the roof splits the difference,
becoming slanted by 22.5 degrees. In operation, the light enters the front face of the prism, bounces off the
top/back face, bounces off one side of the roof, bounces off the other side of the roof, bounces off the front
face, and exits the top/back face.

Brett Erskine · June 16th, 2004, 02:28 PM

Heres how P+S Technik does it.

http://www.pstechnik.de/sheets/downloads/pp-dec12.pdf

Bob Hart · June 28th, 2004, 08:34 AM

On initial iewing of the PRO35 article, I could not find a technical description to match the diagrams but my german is far too poor to find it in any event.

(Some text originally here relating to patent techs deleted by myself until some checks are made.)

June 16th, 2004, 08:28 AM	#1
Simon Fenton New Boot Join Date: Jan 2004 Location: London, UK. Posts: 20	35mm adapters - image correction using Schmidt Prisms thought I'd share this info that I found. An Amici prism is much like a prism star diagonal, except that its hypotenuse, rather than being flat, is ground into 2 faces forming a 90 degree roof. A light ray from the telescope enters the front face nearly flat-on, bounces off one face of the roof, then bounces off the other face of the roof, then exits the top face. The Amici prism diverts the beam by 90 degrees while turning it right side up and correct left-to-right. A Schmidt prism (which many people have been incorrectly calling Amici) turns the beam through 45 degrees while turning it right side up and correcting it left-to-right. Conceptually, take an Amici prism and deform it by pushing its top face down to the 45 degree angle, while the ridge of the roof splits the difference, becoming slanted by 22.5 degrees. In operation, the light enters the front face of the prism, bounces off the top/back face, bounces off one side of the roof, bounces off the other side of the roof, bounces off the front face, and exits the top/back face.

June 16th, 2004, 02:28 PM	#2
Brett Erskine Major Player Join Date: Dec 2003 Location: Anaheim, CA Posts: 445	Heres how P+S Technik does it. http://www.pstechnik.de/sheets/downloads/pp-dec12.pdf

June 28th, 2004, 08:34 AM	#3
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,476	On initial iewing of the PRO35 article, I could not find a technical description to match the diagrams but my german is far too poor to find it in any event. (Some text originally here relating to patent techs deleted by myself until some checks are made.)