The first two DK mirror sets that I have for sale are of 135mm aperture, the so called type 1. The rest of the main parameters being described below:
- D=135mm - useful diameter;
- Fech=3600mm - the system focal length (F/26.7);
- h=489.3mm - the separation between the mirrors;
- e=175mm - back focus;
- d2=28mm - secondary diameter (20.7% linear central obstruction).
All these mirrors are handmade and diffraction limited. In my estimation of ~L/8 wavefront (at the eyepiece) and a Strehl Ratio at least 0.94. They gives excellent images. In this presentation I will show you the Ronchi star test for each set. Outside focus, with 0.1mm wire screen.
Price for one set = 150 euro (+shipping and PayPal fee)
More information in PM.