Antlia Sulfur II (SII) 4.5nm EDGE 31mm Filter (ANT-SII-45NM-EDGE-31MM)
ANT-SII-45NM-EDGE-31MM
Antlia Sulfur II (SII) 4.5nm EDGE 31mm Filter (ANT-SII-45NM-EDGE-31MM)
ANT-SII-45NM-EDGE-31MM
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$329
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Product Description
Antlia H-alpha EDGE narrowband filter optimizes the FWHM (full width half maximum) to 4.5nm bandpass. The suppression of optical density (OD) 5 on unwanted wavelengths and the excellent transmittance characteristics found in the Antlia 3nm Pro series has been incorporated into the 4.5nm EDGE narrowband filters. The result is that these filters deliver superior SNR (signal to noise ratio) and better contrast in your images.
Conventional broader narrowband filters cause a heavy loss in transmission due to the strong Center Wavelength (CWL)-shift. We guarantee T>90% within 1nm range of the center bandwidth, which means that the H-alpha 4.5nm EDGE narrowband filters can guarantee high transmittance for working with both long focal ratios and fast optical systems. Blue-shift data shows that Antlia 4.5nm EDGE filters can be used with nearly all systems as fast as f/3 with minimal loss in emission signal and meets the requirements of fast optics.
Main Features
- High transmittance and narrow bandwidth to maximize contrast
- Steep spectral profile minimizes halos around bright stars
- A single substrate to eliminate internal reflections
- Use in light polluted areas and dark sites
- Extends imaging time when the moon is up
- Antlia narrowband EDGE filters can be used down to f/3 systems with minimal loss of signal
- All Antlia unmounted filters are edge blackened to eliminate internal reflections from stray light
- Superior optical reliability reduces post image processing
- This filter is only effective for deep sky objects that contain SII/Ha/OIII emissions
Specifications
| Model | Sulfur II | Hydrogen-Alpha | Oxygen III |
| FWHM | 4.5nm | 4.5nm | 4.5nm |
| CWL (Central Wavelength) | 671.6nm | 656.3nm | 500.7nm |
| Peak Transmission | >90% | >90% | >85% |
| Blocking | ≥OD5 @ 300-1000nm | ≥OD5 @ 300-1000nm | ≥OD5 @ 300-1000nm |
| Filter Thickness | 2mm+/-0.05mm (1.25"/2"/31mm/36mm) 3mm+/-0.05mm (50mm/50x50mm) |
2mm+/-0.05mm (1.25"/2"/31mm/36mm) 3mm+/-0.05mm (50mm/50x50mm) |
2mm+/-0.05mm (1.25"/2"/31mm/36mm) 3mm+/-0.05mm (50mm/50x50mm) |
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