About this product
Model: antlia_ha_4_5nm_36mm
Part Number: H-alpha 4.5nm Edge 36mm
Antlia 4.5nmnm H-alpha (Ha) EDGE Filter
Antlia H-alpha EDGE narrowband filter optimise 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.
Antlia H-alpha 4.5nm EGDE filters are designed to deliver high transmittance at the 656.3nm line that provides you with the maximum signal to reveal the faintest H-alpha nebulae structures.
Conventional broader narrowband filters cause a heavy loss in transmission due to the strong Centre Wavelength (CWL)-shift. We guarantee T>90% within 1nm range of the centre 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.
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
- 4.5nm FWHM Ha filter - 656.3nm centre wavelength
- High transmittance and narrow bandwidth to maximise contrast
- Steep spectral profile minimises halos around bright stars
- A single substrate to eliminate internal reflections
- Narrowband Objects: H-alpha 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
- Antlia narrowband EDGE filters can be used down to f/3 systems with minimal loss of signal
- 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 H-alpha emissions
- 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): 4.5nm
CWL (Central Wavelength): 656.3nm
Peak Transmission:>90% Blocking: > 5 OD (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
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
Customer reviews
Average Rating (2 Reviews): | |
25 August 2024 | Francis
agree with the other comment, I'm in bortle 6 and the images I'm getting are quality, I got the OII to and i cant see any halos
05 July 2024 | Richard
Good compromise between very narrow band pass filters at 3nm (which need very tight QC to prevent blocking if off band for any reason) and the wider narrowband filters at 6nm. Cheaper too, and can accommodate a wider range of focal ratios.
I'm bortle 5 and the HSO set works as it should. Excellent signal, and excellent service from FLO as usual
FAQ
Please fill in the form below to ask a question.