I need your help to figure out my back focus math. I have a GT71 with a Flat 6AIII, a ASI533MC pro, a ZWO filter drawer and an adapter 42 to 48.
This is what I have so far:
According to the WO website the Flattener on a GT71 requires a back focus of 64.1mm.
The camera has 17.5 mm
The ZWO filter drawer has 21 mm.
The adapter is 16.5 mm.
These adds up to 55 mm (coincidence??)
Does this means that I need to compensate (adjust) the flattener to 9.1 to reach my 64.1? Am I missing something?
Thanks so much guys for your comments.