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Vignette is pretty heavy with a full-frame DSLR on the Newt, but a crop sensor isn't too bad. That and the light blocked by the secondary might add up to a little, but it still surprises me the Newt isn't significantly brighter.
I use a cheshire eyepiece for collimation, no lasers involved. The secondary was WAY off - about 5-6mm too far down the tube.
Anyway, I've just re-assembled my old Skywatcher equivalent and it's exactly the same exposure as the GSO - in fact the GSO is ever so slightly brighter. It's weird!! Maybe there was some fogging on one of the surfaces last night, perhaps the camera-end glass of the CC. All the subs I took were extremely dim despite really cranking the ISO; same results with two different DSLRs. I'll try again tonight, weather permitting.
I just spoke to Luke at Andrews; if I can get to Sydney next week he's agreed to swap it for another one. You're right, not his / their fault at all. The last GSO telescope I bought from them was perfect and nicely collimated; this seems to be a rare miss.
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