First drift attempt M33

[MilwaukeeLion]

First drift align attempt from last night - PHD2, EQMOD, Stellarium Scope.  Improvement over my previous M33 for sure & captured faint galaxy above M33, overall seeing was not best.  Came away with some positives, accuracy much improved over my eyeball polar align - reduced backlash.  Watched tracking graph jump every time camera fired, things not as locked down as I thought.  Still some misshapes lower right and circular pattern in final stacked image, difficult to remove without darkening.  Maybe moisture, flattener, spacing issue, LP or dozen other things?  

18 x 180 sec subs, 10 darks, 15 bias, 10 flats, DSLR, ED80TCF, Atlas EQ-G, SSAG, DSS, PS.

ML

[cuivenion]

Great picture! There seems to be circular blue banding in both the widefield images, any idea what would cause this?

[MilwaukeeLion]

6 hours ago, cuivenion said:

Great picture! There seems to be circular blue banding in both the widefield images, any idea what would cause this?

I think its just moisture, but I didn't look at lens when I was finished. I checked spacing of DSLR chip to Orion field flattener for short refractors and its very close to 55mm.  Can't get it any closer than that, only thing I can adjust is field flattener to telescope, going to have another session tonight see if it repeats.  Someone suggested this flattener works well with chip sizes 26mm and smaller, if that's the case it can't handle my Nikon chip / will have to crop.