The Chroma H-beta 5 nm 50x50 mm Unmounted (SKU: CT-27005-50X50) is a narrowband filter in a square format, designed for professional astrophotography of emission nebulae. With a 5 nm bandwidth, it effectively isolates the H-beta line (approximately 486 nm), providing high image contrast and greater light transmission than narrower 3 nm filters.

Key features

• 5 nm bandwidth optimized for the H-beta line (approx. 486 nm)
• bandwidth transmission at approximately 99%
• hard coatings applied using the reactive magnetron sputtering method – high durability and resistance to environmental factors
• anti-reflective coatings on the back surface minimize reflections and ghosting
• all Chroma Astronomy filters are parfocal to each other
• designed for optical systems f/4 and faster, also works well at f/3
• not suitable for observing the Sun

Set components

• H-beta filter 5 nm 50x50 mm unmounted – CT-27005-50X50

Technical parameters

• type: H-beta narrowband filter for astrophotography
• format: 50x50 mm, unframed
• bandwidth: 5 nm
• central wavelength (CWL): approx. 486 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)