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About this product
Model: antlia_oiii_3nm_125
Part Number:
Antlia 3nm OIII Pro Astronomy Filter
Antlia OIII Pro narrowband filter optimise the FWHM (full width half maximum) to 3nm bandpass. As the bandwidth becomes narrower, the 3nm Pro narrowband filters enhance contrast of emission targets by lowering the unwanted background signal. Antlia OIII 3nm Pro filters are designed to deliver 85% transmission at the 500.7nm line which provides you with the maximum signal and well defined nebulae structures.
Conventional broader narrowband filters cause a heavy loss in transmission due to the strong Centre Wavelength (CWL) shift. We guarantee T>85% within 1nm range of the centre bandwidth, which means that the 3nm Pro narrowband filter can guarantee high transmittance for working with both long focal ratios and fast optical systems. Blue shift data shows that Antlia 3nm Pro 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 like Hyperstar and RASA.
The out of band blocking specification is rated OD5 (0.001%) 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 3nm Pro filters are designed to minimise halos around bright stars.
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
- 3nm FWHM OIII filter - 500.7nm centre wavelength
- High transmittance and smallest bandwidth to maximise contrast
- Steep spectral profile minimises halos around bright stars
- Suitable for imaging narrowband objects: OIII Emission Nebulae, Planetary, Wolf Rayet Nebulae and Supernova Remnants
- Use in light polluted areas and dark sites
- Extends imaging time when the moon is up
- Suitable for fast systems down to f/3 without loss of signal
- 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
Blue 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 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): 3nm
CWL (Central Wavelength): 500.7nm
Peak Transmission: ＞85%
Blocking: > 5 OD(0.001% 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
Single / Non-glued substrate
Filter Ring:
1.25’’(M28.5*0.6) or 2’’(M48*0.75)
Ultra-thin filter cell to minimise vignetting
Black anodised finish Laser engraving
No fading
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