This is for Takahashi FS60C owners - if there are any on this forum?
Not sure of the experience of others with the f/6.2 flattener (not the more recent multi-flattener) and use with consumer digital cameras. But referencing the configuration in the FS60C system chart, I found it impossible to obtain a flat field.
A little bit of forum reading tends to indicate the same.
The previous owner, an IIS member, made up a wider T-Mount front section (it comes in two bits). The difference of several millimeters made all the difference - see attached GIF.
Thanks JG.
Note: the GIF images are of the top right corner of the frames but not the same star field - that would be too organised.
There is a little degradation resizing the GIF and possibly due to random sampling error in the single sub but otherwise a significant and usable improvement.