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.

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.

This OIII filter particularly enhances planetary nebulae in larger telescopes. Narrowband filter for high transmission, with high blocking of unwanted longer wavelengths to yield high-contrast images. Ion beam technology and optical glass produces low scatter in a hard stable coating to reduce changes due to temperature and humidity. Optical quality ground and polished BK7 glass yields sharp star images - even when filter is placed in front of diagonal.

This OIII filter particularly enhances planetary nebulae in larger telescopes. Narrowband filter for high transmission, with high blocking of unwanted longer wavelengths to yield high-contrast images. Ion beam technology and optical glass produces low scatter in a hard stable coating to reduce changes due to temperature and humidity. Optical quality ground and polished BK7 glass yields sharp star images - even when filter is placed in front of diagonal.

The Type-A is a dual band filter with different dielectric coatings on each side of the substrate. The dual band nature of the filter permits green and red through while rejecting all other visible colors. The effect is to enhance detail on the Martian surface while preserving the natural color of the polar caps and rest of the surface. Since this filter provides a most natural view, it is highly recommended for public viewing.

The Bandmate^TM Mars Type-B filter is a high efficiency, single band dielectric coating that achieves penetrating views of the Martian surface. The surface appearance is similar to that of the popular #21 filter. However, the Type-B features a broadband anti-reflection coating on one side and filter coating on the other that makes it far more efficient.