ASI1600 + EFW coma corrector extender / spacer problem

[RolandKol]

Another question, - for the future
Did anyone manage to attach Rotator to this train? SW CC>ZWO Filter Wheel>ASI1600?

[Stub Mandrel]

I've just taken some 'real world' measurements.

It looks to me that ZWO have supplied a pretty much optimal set of adaptors, assuming a standard 55mm back focus for the typical field flattener or coma corrector.

Without the EFW:

ASI1600 --->  21mm T2 adaptor** ---> female/female adaptor** ---> T2-48mm adaptor**

6.5mm + 21mm + 11mm + 16.5mm =   55mm

**supplied with ASI

 

With EFW:

ASI1600 --->  EFW --->  T2-T2 male/male adaptor* ---> female/female adaptor** ---> T2-48mm adaptor**

6.5mm + 19.97mm + 1.96 mm + 11mm + 16.5mm =   55.93mm

*supplied with EFW

**supplied with ASI

Allowing for ~0.7mm shortening of the light path by the filter, this is pretty close again at 55.2mm.