I have been improving my guiding and focussing of late, but notice that the stars out towards the edges are still egg shaped in the images. Is this an inherent problem with reflectors or just a problem with my mirror. Would some sort of field flattener help.
Well if it is the 250mm dob that your using then the answer is yes, its to do with the hyperbolic nature of the mirror that light hitting the outer 1/3 of the mirror focus's at a different part.
If your doing photography i suggest you invest in a 250 dollar MPCC (Mulit purpouse Coma Corrector) this will clean up the image and is designed for newts with a f# between 4 - 6 with f5 working the best.
Thanks Brendan. I thought it would be something like that, but had to confirm it. Using the 6" F5 so the Baader one looks ideal, just ordered one from MyAstro.