10" Schmidt-Newtonian coma problem

I recently started using my 10"sn for some astrophotography and have found it to have considerable coma in the corners. I have seen reviews on the 8" that said the corrector totally eliminates the coma. Am I wrong to assume the same for the 10"? Is it possible that the mirror might be too tight in its cell causing this?

The first one that shipped to me from Meade, the mirror did a nosedive into the corrector. The technician told me on the phone that they changed the design of the clips holding the mirror in place.

Any thoughts?

I'm no expert but I've read the Schmidt design "merely" reduces coma by half, so the (unuseable) f/4 coma is corrected to more like f/6, i.e. still present but useable. (I have the SN6 f/5 which is pretty good coma-wise.) That said, given the superlative astrophotos done using the SN's, it's quite possible your scope may need some work. However, re-collimation of the SN is supposed to be a pain and some people eventually gave up and shipped their scopes back to Meade (so try not to void the warranty). Maybe if you used CCD the corners/coma wouldn't be a problem?

-- William