Chroma H-alpha 8 nm 2" mounted (SKU: CT-27003-2M) is a narrowband filter designed for astrophotography of emission nebulae, made in the 2" standard. Thanks to the 8 nm bandwidth, it ensures high light transmission, which facilitates the registration of fainter objects and shortens the exposure time while maintaining good selectivity of the H-alpha line.

Key features

• bandwidth of 8 nm in the H-alpha line (approx. 656 nm)
• transmission in the band of approximately 99%
• hard coatings applied using the reactive magnetron sputtering method – high durability and resistance to changing conditions
• anti-reflective coatings on the back surface minimize reflections and ghosting
• all Chroma Astronomy filters are parfocal to each other
• intended for optical systems with a f/4 aperture and slower
• the filter is not intended for observing the Sun

Set components

• H-alpha 8 nm 2" filter in the holder – CT-27003-2M

Technical parameters

• type: narrowband H-alpha filter for astrophotography
• diameter/fitting: 2"
• bandwidth: 8 nm
• central wavelength (CWL): approx. 656 nm
• transmission: approx. 99%
• optical substrate: 3.0 mm thick glass
• coating technology: reactive magnetron sputtering (hard coatings)
• coating construction: main layer on the front side, AR coatings on the back side
• Transmitted wavefront accuracy: better than 0.25 waves/inch
• parfocal: yes (with other Chroma Astronomy filters)
• production: USA (Vermont)