The astrographs in the Cat series are very easy-to-use optics for nature and astrophotography. They are available in the RedCat and SpaceCat colour variants.
At the heart of the optical set-up is the Petzval design: four lenses in three elements provide a colour-corrected and, above all, flat field of view. No external field flattener lens (flattener) is required!
Other special features include the field rotator with filter holder, with which the camera can be rotated, and the tilting collimator for perfect collimation of the image plane with the camera’s sensor plane.
The patented William Optics Bahtinov mask is integrated into the lens’ dust cap. With this focus mask it is very easy to set the correct focus for bright stars.