Baader T-2 Zenith prism 1 1/4 1B

Baader T-2 zenith prism (Zeiss prism, with male/female T-2 photo thread) The Zeiss Jena T2 zenith prism offers a large aperture, you have about 35mm free aperture, which is significantly more than with 1.25". The T2 housing also allows connection to 2", both on the eyepiece and telescope side, using suitable 2" adaptors. This application makes sense with devices that have a very tight back focus, where you can no longer get into focus with normal 2" star diagonal mirrors. You can use 2" eyepieces up to approx. 40mm field aperture, despite the slightly smaller prisms, the view does not become more unsteady, only the outermost edge becomes slightly darker.