I've been watching the PlaneWave group to see what kind of imaging results people are getting with the PlaneWave CDK12.5. PlaneWave claims that the Corrected Dall-Kirkham design is more affordable than an RC design, and can produce quality images. From their website:
The goal of the design is to make an affordable astrographic telescope with a large enough imaging plane to take advantage of the large format CCD cameras of today. Most telescope images degrade as you move off-axis from either coma, off-axis astigmatism, or field curvature. The CDK design suffers from none of these problems. The CDK is coma free, has no off-axis astigmatism, and has a flat field. The CDK consists of three components: an ellipsoidal primary mirror, a spherical secondary mirror and a lens group. All these components are optimized to work in concert in order to create superb pinpoint stars across the entire 42mm image plane.
I think this image speaks volumes about the performance. Seems PlaneWave's claims are accurate.
I like having long-term equipment acquisition goals. While I have my widefield dream setup, I hope to someday have a long focal length setup that is portable. For a long time, I had planned to get an RCOS 12". But I'm rethinking that based on the CDK price and performance.