I'm looking around for an imaging refractor and can't decide.
I'm using a mono camera, 294MM with LRGB,SHO.
Do I still need a triplet to avoid CA even though I will be focusing on each colour separately? My guess is that problems will arise when shooting L.
I want to image large targets such as m31, m42, Elephants trunk nebula, etc. I find my 130pds just a little too cropped in for these. Collimation is becoming a pain and I'm not sure if I'm really keen on the diffraction spikes anymore.
Currently I'm looking at WO 72GT, SW 72ED, SW 80ED. These are within my budget.
Thanks,
Alan