fenerit wrote:
I would suggest also a shot to the nearby galaxy NGC 4631 (Whale galaxy) still in Canes Venatici and NGC 4565 (Needle galaxy) in Coma, they are good subjects for your equipment.
I'll put them on my observation list

Apparent magnitude of 10.42 (NGC 4565) is a bit of a challenge with my exposure times though. But I'm trying to get a used EQ-6, which should allow for longer exposures with less rejects.
fenerit wrote:
A good 2x Barlow linse maybe could be your next acquisition, inserted between the coma corrector and the camera it does extend the focal lenght of the scope and you will go closer.
I thought about this, but I was not sure if it wouldn't simply enlarge the image (or reduce the FOV), without actually helping to get more details? I felt that I was already oversampling the resolution provided by the 6" with the APS-C camera sensor...
Do you have a link to some good Barlow?
Depending on the costs, it could be better to invest in a larger scope - but that's for the more distant future.