I have ordered a Baader 1:1.25 GPC to complete the PST mod on my 6" f/8 to correct it to f/10.
Then the sun came out briefly. So I measured the solar light cone at the etalon 200mm inside focus.
After all, this is where the GPC wants to sit close in front of the etalon.
Guess what? The solar light cone measures somewhere around 30mm Ø at that point.
I'm afraid the remaining cloud made it hard to get a properly sharp disk.
It seems much of the light from a 6" f/8 never passes through the 20mm Ø PST etalon.
All it does is heat the etalon surroundings. i.e. AOC etalon adapter.
Am I mistaken about this or is this something we have all overlooked?
Should we all be looking for a much better matching, smaller aperture, shorter focus, f/10, donor refractor?
