Stevick-Paul -Brunn

Although Brunn was the first to make a 4 mirror design the Stevick-Paul is more widely known.  Stevick-Paul telescopes are off-axis versions of Paul 3-mirror systems with an added flat diagonal mirror but to me it’s just a Schief behind a Schief.  It is well corrected although it has a lot of field tilt.  With 4 mirrors it will require enhanced coatings of the light loss will be considerable.

8 Inch F12.8 Stevick-Paul

8 inch F12.8 Stevick-Paul