[Nico13 (Ken)]

Some time back there was a discussion re vignetting with SCT's and SLR's in particular with the focal reducer flattener in the image train.
For some time I've mulled over ways around this and recently while reading up on telescope design and considerations I saw it mentioned that the reducer correctors should be as close to the image sensor as possible.

Thinking about that and the Orion flattener I use on the ED80 is mounted directly to the camera and that works fine, it even helps on the SCT (Meade 8") So looking at my SCT setup with the reducer fitted directly to the back of the scope and then focuser before camera adapter I wondered if by any chance the camera adapter threads would be the same as the flattener and bingo they are.

So next step, move the flattener further back in the image train to just in front of the camera.
The aim is to reduce the amount of vignetting but there was a surprising additional effect as well.
See my next post shortly with some test flats ect for the initial results prior to field testing.

Image one and two Original setup
Image three and four fitting flattener to camera adapter
Image five new location of flattener