Antlia SII 4.5nm EDGE Filter 50mm
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Vai al moduloAntlia SII 4.5nm EDGE Filter 50mm – Ultra-Narrow Band with High Transmission
The Antlia SII EDGE 4.5nm filter is an ultra-narrow band filter designed to maximize contrast when imaging emission nebulae. Centered on the SII line at 672.4nm, it combines the 4.5nm bandwidth with the excellent transmission characteristics of the PRO 3nm series, guaranteeing a higher signal-to-noise ratio than conventional broader narrowband filters, which suffer heavy transmission loss due to center wavelength (CWL) shift.
Thanks to OD5 (0.001%) blocking on unwanted wavelengths, Antlia guarantees transmission above 90% within 1nm of the center band, making this filter suitable for both long focal ratios and fast optical systems down to f/3, with minimal signal loss. The unmounted 50mm format, with increased 3mm thickness for flatness over larger surfaces, is designed for large-format filter drawers and filter wheels.
Key Features
- 4.5nm bandpass (FWHM), centered at 672.4nm
- Peak transmission >90%
- Out-of-band blocking OD5 (0.001%) from 300 to 1000nm
- Usable down to f/3 with minimal signal loss
- Monolithic, non-glued Schott substrate, hand-blackened edges
- 50mm unmounted format, 3mm thickness
Technical Specifications
| Filter type | Ultra-narrow band SII EDGE |
| Center wavelength | 672.4nm |
| Bandpass (FWHM) | 4.5nm |
| Peak transmission | >90% |
| Out-of-band blocking | OD5 (0.001%) @ 300-1000nm |
| Format | 50mm (unmounted) |
| Substrate | Schott, 3mm ±0.05mm thickness |
| Surface quality | 60/40 (MIL-O-13830) |
| Transmitted wavefront | λ/4 or better |
| Parallelism | <30 arcsec |
| Warranty | 3 years against delamination |
| Recommended use | Deep-sky imaging on large-format filter wheels |
As the SII component of the SHO EDGE set, this filter is ideal for high-contrast imaging of emission nebulae, supernova remnants and planetary nebulae, offering better performance than the previous PRO 3nm generation thanks to its improved balance between bandwidth and transmission.