I'm thinking about moving on from my EdgeHD scopes to CDK. In consideration are Planewave 12.5 and 14. I currently have two 11" EdgeHD and one 8". I'm frustrated with Edge design for imaging due to:
- Recollimation seems to be required every session. Especially at sub .5" pixel scales and because I set up / tear down each night.
- I think mirrors and/or the corrector plate shift slightly throughout the night causing changes in star shapes.
- Stars suffer from color fringing. Looking at the Edge spot diagrams I don't think this is surprising (excluding the 9.25").
- Difficulty cooling the tube to ambient. I live in a humid area so I haven't used fans yet.
Some questions about CDK are:
1) Is collimation easier with a CDK than an SCT? Is the elliptical CDK primary more forgiving than the spherical SCT primary - how much so?
2) Any issues with star shapes changing during the night or from session to session?
3) Have people found the advertised 52mm corrected circle of the Planewave CDKs to be accurate - any color fringing?
4) How well does the focuser and ASCOM software work?
5) Is the open-tube CDK 14 a bad choice for humid environments?
6) Have people been happy with the Delta T cooling and dew prevention system?
7) Is a dew shield recommended for the 12.5"? - I assume not.
Comments on differences between these designs are welcome, especially from those who've used both. My AP1100 mounts should have no trouble handling the 12.5 or 14.