Thanks Susan that all makes sense, i had been confused by the extra magnification from the distance to the focal plane not realising this was exclusive to eye-piece projection. So thank you very much for explaining
Looks like i will have to move the primary mirror forwards a couple of cm's to achieve focus on the stars. Can make it focus but have to remove the locking screws and push the collimating screws right in, and that makes me nervous on the EQ type mount!
I actually want to extend the tube anyway to get a larger 75% illuminated area for the sensor or in this case the film. This is not something that people seem to talk about here - how important would this be for pics (if you don't mind me asking) ?
many thanks