Hi all,
Last night I managed to significantly reduce tilt with the Riccardi reducer. It took 0.1 mm of camera adjustment to correct it. There is some slight curvature still present, but not sure if that can be corrected with playing with the spacing. It might be as well a limitation of the Riccardi, so I think I will leave things as they are. I have learnt that precision is essential with a refractor at f/4.5...
A star field for a reference:
http://www.astrobin.com/full/293135/0/
It's imaging time!
Suavi