I‘m having a Skywatcher 130PDS and would like to try a binoviewer with it. As the 130PDS is intended for DSLR photography, I‘m hoping that I‘ll reach focus with a 1.6 GPC, giving me an effective focal length of 1040mm. I’ve read that cheap BVs support about 18mm clear aperture, so 25mm Plössl eye pieces would already be slightly vignetting.
This means the wider possible magnifications, apparent and true fields would be:
25mm 50°: 42x 1,2°
20mm 50°: 52x 1.0°
Is this correct? Does anyone have any experience using this scope with binoviewers?