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About this product
Model: antlia_oiii_7nm_36mm
Part Number: SHO 7nm Prime set 36mm
Antlia Ha / SII / OIII (SHO) 7nm 36mm Unmounted Prime Filter Set
The Antlia 7nm Prime narrowband filter optimise the FWHM (full width half maximum) to 7nm bandpass. The suppression of optical density is (OD) 4 on unwanted wavelengths.The excellent optical coating characteristics found in the Antlia 3nm Pro series has been incorporated into the 7nm Prime narrowband filters. The result is that these filters deliver superior SNR (signal to noise ratio) and better contrast in your images. Antlia 7nm Prime filters are designed to deliver 90% transmittance at the CWL SII 671.6nm, Ha 656.3nm and OIII 500.7nm lines that provides you with the maximum signal and well-defined nebulae structures.
The bandpass of the Ha filter is wide enough (7nm bandwidth) to pass emission lines at NII 654.8nm and NII 658.3nm.
The out of band blocking specification is rated OD4 (0.01%) which delivers an excellent SNR (signal to noise ratio) and effective cut-off rate to minimise interference from other wavelengths.Improved sharp cut off astrophotography 7nm Prime filters are designed to minimise halos around bright stars. Antlia 7nm Prime filters can be used with nearly all systems as fast as f/2 with minimal loss in emission signal and meets the requirements of fast optics.
IMPORTANT: These filters are NOT designed for observing or photographing the Sun. DO NOT use these filters to observe or photograph the Sun. If you do it will result in permanent eye damage!
FEATURES
- 7nm 36mm unmounted filters
- 90% transmittance at Central Wavelength (SII 671.6nm, Ha 656.3nm and OIII 500.7nm)
- Wider FWHM, 7nm Prime narrowband filters can be used with fast optics of f/2 with minimal loss of signal
- Steep spectral profile minimises halos around bright stars
- A single substrate to eliminate internal reflections
- Narrowband Objects: Emission Nebulae, Planetary, Wolf Rayet Nebulae and Supernova Remnants
- Use in light polluted areas and dark sites
- Edge blackened to eliminate internal reflections from stray light
- 2mm+/-0.05mm thickness for 1.25", 2" mounted, 31mm and 36mm unmounted
- 3mm+/-0.05mm thickness for 50mm and 50x50mm unmounted
- Fine-optically polished on both sides
Transmission Chart
Purple Line - Represents the transmission curve of the filter.
The Major Emission Lines of Nebulae: H-α (656.3nm), H-β (486.1nm), OIII (495.9nm) and OIII (500.7nm)
The Major Emission Lines of Artificial Light Pollution: Hg / Mercury (435.8nm, 546.1nm, 577nm and 578.1nm), Na / Sodium (598nm, 589.6nm, 615.4nm and 616.1nm)
Specifications
Basic Substrate: Optical, Single / Non-glued substrate
Filter Thickness:
2mm+/-0.05mm for 1.25", 2" mounted, 31mm and 36mm unmounted
3mm+/-0.05mm for 50mm and 50x50mm unmounted
FWHM (Full width at half maximum): 7nm
CWL (Central Wavelength): SII = 671.6nm, Ha = 656.3nm, OIII = 500.7nm
Peak Transmission: ＞90%
Blocking: > 4OD(0.01% out of band blocking) @ 300-1000nm
Surface Quality: S/D (scratch/dig)= 60/40 (Refer to MIL-O-13830)
Transmitted Wavefront: Lambda/4 or better.
Parallelism: less than 30 arcsec
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