Williams Optics Flattener 4

[jabberwock48]

I have an A&M 130mm APO which has a 2in Feathertouch focuser with about 2in of travel. For imaging it needs a 2in extension to achieve focus and with my QHY8 Pro with 23mm backfocus it needs a short T spacer as well.

Having heard that a Williams Optics Field Flattener 4 would suit the scope I tried one tonight, using a 32mm T spacer to set the QHY8 Pro 55mm from the Flattener 4 i.e. the spacing of a DSLR for which it is intended. With a 2in extension in front of the Flattener it was a long way out of focus with the scope focuser right in. Without the 2in extension it was closer but still out of focus by a bit with the focuser right in. As expected adjusting the lens to chip adjustment on the flatenner had no effect on the focus.

Any ideas please?

[sgazer]

looks like the flattener is also a 0.8x reducer so brings the focus point in. I tried this with a 0.63x reducer on a C80-ED and had to make a special adapter to mount the SCT reducer directly to the Canon adapter. Have you got a photo of your setup?