Antlia H-Alpha 3.5nm Filter 2"
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Vai al moduloAntlia H-Alpha 3.5nm Filter 2" – Ultra-Narrow Band for Astrophotography
The Antlia H-Alpha 3.5nm filter is an ultra-narrow band filter centered on the ionized hydrogen emission line at 656.3nm, with a bandwidth of just 3.5nm. It guarantees transmission above 88% on the H-Alpha line and out-of-band blocking of OD3 (0.1%) from 300 to 1100nm, for maximum contrast even under heavy light pollution and during moonlit nights.
Designed specifically for new-generation CMOS cameras and fast telescopes down to f/2.0, the filter uses a monolithic, non-glued Schott substrate with double-sided polishing and multi-layer nano-coating. The edge is hand-blackened – a distinctive feature of Antlia's build quality – to completely eliminate stray light and halos around bright stars.
The H-Alpha component of the SHO set (H-Alpha + OIII + SII), it enables high-contrast imaging of emission nebulae, supernova remnants and planetary nebulae, with the option to enrich RGB images with the H-Alpha channel for greater structural definition.
Key Features
- 3.5nm bandpass – maximum contrast and light pollution suppression
- Transmission >88% on the H-Alpha line at 656.3nm
- OD3 (0.1%) blocking from 300 to 1100nm
- Monolithic, non-glued Schott substrate, parallel ±0.05mm
- Hand-blackened edges to eliminate stray light and halos
- 2" mount (M48x0.75), compatible down to f/2.0
Technical Specifications
| Filter type | Ultra-narrow band H-Alpha |
| Center wavelength | 656.3nm |
| Bandpass (FWHM) | 3.5nm |
| H-Alpha transmission | >88% |
| Out-of-band blocking | OD3 (0.1%) @ 300–1100nm |
| Format | 2" (mounted, M48x0.75) |
| Substrate | Schott, 2mm ±0.05mm thickness |
| Surface quality | 60/40 (MIL-O-13830) |
| Flatness | 1/4λ |
| Parallelism | 30" |
| Coating | Multi-layer nano-coating, double-sided |
| Focal ratio | Down to f/2.0 |
| Recommended use | Mono CCD/CMOS, SHO imaging, emission nebulae |