My ES MN is long, tough to balance, hard to collimate, has odd diffraction spikes, has a mediocre focuser, and the collimation shifts depending on where the scope is pointing. It's excellent visually but has been the source of a lot of frustration when imaging. In an attempt to simply things I've picked up a WO GTF81. It's light, no collimation needed, has a great focuser, is well corrected, and has great glass.
With my NEX-5 on the MN I'm imaging at about 1.44" ppx @ f/4.8. With my a6000 on the WO I'm imaging at about 1.50" ppx @ f/6.6. Now, the a6000 has a QE of 61% whereas the NEX-5 has a QE of 32%. On the surface it looks like I'll be imaging at about the same resolution with a very similar exposure length. The resolving power of the of the WO seems to be about 1.43" so I shouldn't be losing any detail.
The only unaccounted for variable is that the NEX-5 is modified while the a6000 isn't. Considering I'd be imaging through a refractor, it should be irrelevant (as I'd have to use a UV/IR filter on the NEX-5 anyway.)
Am I overlooking anything in my calculations? Since my seeing is usually about average I'm not too worried about loosing out on the 0.76" resolving power of the MN.