Focal point for Celestron 8" with .63 focal reducer?

[kmaslin]

Can someone give the distance for the focal point for a Celestron 8" SCT (not Edge) with a 0.63 Celestron focal reducer, with clear notes as to where to measure from 🙂

Various posts on forums give different measurements and also unclear where actually measured from. Camera is an Altair 294C which has an offset of 17.5mm to the sensor

Sketch would be great 👍 

Cheers

Keith

[newbie alert]

I answered this the other day but can't find what I wrote.. I've had some fun with my sct, collimation and spacing issues I feel I'm now close, don't think I'm too far away but with the standard sct( I'm using the xlt version) and the celestron. 63 reducer/flattener ) I don't think you will get a true flat field.. think you need the edge hd and the .7 reducer for that.. For the time being I'm going to use what I have but get the best I can from it

Celestron say 105 from the reducer threads, if I do that my stars aren't right but I think as my adapter doesn't screw right on..I think from memory I measured 106.67 but to the flat of the reducer instead of the threads