Antlia OIII 3.5nm Filter 50mm
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Vai al moduloAntlia OIII 3.5nm Filter 50mm – Ultra-Narrow Band for Astrophotography
The Antlia OIII 3.5nm filter is an ultra-narrow band filter centered on the doubly ionized oxygen emission line at 500.7nm, with a bandwidth of just 3.5nm. The extremely narrow bandwidth guarantees transmission above 88% on the OIII line and out-of-band blocking of OD3 (0.1%) from 300 to 1100nm, ideal for shooting 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 unmounted 50mm format, with increased thickness for flatness over larger surfaces, is designed for large-format filter wheels, with hand-blackened edges to eliminate stray light.
An essential OIII component of the SHO set (H-Alpha + OIII + SII), it enables high-contrast imaging of planetary nebulae, supernova remnants and emission nebulae in the Hubble Palette on large-format sensors.
Key Features
- 3.5nm bandpass – maximum contrast and light pollution suppression
- Transmission >88% on the OIII line at 500.7nm
- OD3 (0.1%) blocking from 300 to 1100nm
- Monolithic, non-glued Schott substrate, hand-blackened edges
- 50mm unmounted format, increased 3mm thickness
- Compatible down to f/2.0
Technical Specifications
| Filter type | Ultra-narrow band OIII |
| Center wavelength | 500.7nm |
| Bandpass (FWHM) | 3.5nm |
| OIII transmission | >88% |
| Out-of-band blocking | OD3 (0.1%) @ 300–1100nm |
| Format | 50mm (unmounted) |
| Substrate | Schott, 3mm ±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, large-format filter wheels |