The Baader H-Beta 5.5nm filter is specifically designed for visual observation of faint emission nebulae under bright skies. Unlike H-alpha filters, which are extremely difficult to use visually due to the lack of sensitivity of our eyes at the deep red end of the spectrum, H-beta emissions are very close to where our eyes are most sensitive. Because of quantum-mechanical coupling with H-Alpha, you can see many of the same structures through an H-Beta filter. This makes it act like a visual H-Alpha filter.
Baader CMOS-Optimized filters - advantages
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Very high contrast due to steep edges of the coating
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Reflex-Blocker coatings to minimize reflections caused by correctors, reducers and other optical elements
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Standardized thickness for maximum possible parfocality - less need to refocus due to different filter thicknesses
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Blackened edges with front-side markings
- Each filter is individually fine-polished and coated with sealed coating edge, preventing moisture ingress
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Life-Coat for hardness and age-resistance, making the filters able to withstand tougher conditions for longer
For more information on Baader's new generation of CMOS-optimized filters, check out this blog post!