Al,
Would it move the zero image and the spec to far apart? Wouldn't matter if you dont need the zero image in callibration.
I think there must be a point where resolution of the spectrum would not be improved due to the resolution of the grating (lines/").
I moved my grating out to about 35mm and focus is a real issue, but I just get the full spec and zero image in the frame of the ST7.
I'm no expert, as can be seen, just my thoughts.
