Hi,
I have for a long time been working on a project where I replace my 2.5" field flattener with a bigger 3". I have a Canon 6D full frame camera and got a little to much vignetting from the earlier field flattener. Lot of mechanical problems to solve when fitting in a bigger field flattener and I have try to limited the problems by carefully choosing the correct parts.
I have now come that long that I can do some tests and the results are wonderful, almost no vignetting and I can use the fullframe sensor to the last pixel except where the camera mirror is.
I have written about my project so you can follow it if you have something simular in mind:
http://astrofriend.eu/astronomy/proj...flattener.html
Only one drawback, the f/7 telescope setup is slower than f/5.3, in practice not that big difference because now I can use bigger part of the sensor when I don't have to crop away the vignetted parts.
/Lars
