Quote:
Originally Posted by gb44
Kevin,
Does the blue channel bloat more than R or G given that you achieved perfect focus with each colour filter?
How much of a difference is there between focus for each filter? Does the Bahtinov mask work for each filter?
I ask as I have no experience with filters and am considering the difficulties with narrowband stuff .
Cheers
GlennB  |
Hi Glen, yes the blue filter bloats quite badly even though it's individually focused. I too thought I could just get away with focus for each filter, but blue bloats just the same.
There is little to no difference between focus for each filter. They are parfocal so normally don't need much, if any refocusing at all. But I did it anyway.
Yes the Bahtinov mask works for each filter.
This is just R/G/B not narrow band. I think why double stacking worked with my blue filter is that the Baader Semi-Apo clips the blue channel by 50%, thereby making it narrower than normal.