[g__day (Matthew)]

So I have a 7 position 36mm filter wheel and the standard ZWO RGB Ha OIII SII filters Bintel sold years ago - I have never check the offset required between the Luminance filter and all the others - nor created flats for each filter.

Is this very important with these filters? Do folk with these filters find them zero offset - or do you really need to set this up carefully - just curious!