High-performance, dielectric, squarewave "UHC" type general purpose narrow-band filter great for all nebulae types and instrument sizes.
Red blocking allows brighter, sharper star images not plagued with red fringing seen on most filters of this type.
Highest transmission in critical bands
Optical quality ground and polished BK-7 substrate means no loss of sharpness - even when used in front of mirror diagonals.
100% quality control: