The Sol'Ex Pro version has an adjustment ring for the collimator block. It works better then version 1 but still it's difficult to get a sharp image. Christian Buil provided an exact number for the distance of the collimator block: 88,5mm. This setting is explained in below. Be aware this distance is for H-Alpha. I asked the question about CaII H/K line and this was Christian's response:
Regarding a question I was asked: the 88.5 mm value I recommend is optimal for H-alpha and, more generally, for the visible spectrum. For the Ca II H & K lines, it is preferable to aim for 88.8 mm. This corresponds to about 0.3 turn of the adjustment ring when switching from H-alpha to Ca II directly on the telescope, without having to disassemble the instrument.So te difference between H-alpha and CaII H/K is according to Christian 0,3mm.
I''m using the distance of the opening in the collimator block to adjust for H-alpha and CaII H/K.
As a base this is about 6,24mm and will be 9,24mm for CaII H/K
