View Single Post
  #2  
Old 17-01-2019, 09:53 PM
gregbradley's Avatar
gregbradley
Registered User

gregbradley is offline
 
Join Date: Feb 2006
Location: Sydney
Posts: 17,877
Per Astrodon for filters to be parfocal they need to be very much the same thickness. Its dependent on the thickness of the filters.

I found Baaders not to be parfocal despite advertising they were. The only ones I have had that are parfocal are the Astrodons.

I routinely focus my luminance filter and its accurate for all of them including the narrowbands. Perhaps there is some slight deviation between them which I haven't bothered to chase down as they are workably close.

Greg.
Reply With Quote