This H-alpha 3nm Pro narrowband filter is the upgraded version of the Antlia H-alpha 3.5nm filter. The narrower bandwidth of this filter enhances the contrast of nebulae that emit H-alpha by decreasing transmission of out-of-band wavelengths from light pollution, the moon, and chromatic aberration of bright stars. The filter rejects out-of-band wavelengths by up to 5 OD (99.999%).
This filter is suitable for imaging most emission nebulae, planetary nebulae and supernova remnants with monochrome astronomy cameras. It can bring out a tremendous amount of detail in nebulae where H-alpha emission is present. Because the filter passes little light outside the H-alpha band, longer exposure times and larger apertures or faster focal ratios may be necessary.
The H-Alpha 3nm Pro filter is designed to deliver >90% transmission at the center wavelength of 656.3nm. The transmission of the H-alpha 3nm Pro over its working bandwidth guarantees high transmittance when working with both long focal ratios and fast optical systems (as fast as f/3).
For the H-alpha 3nm Pro narrowband filter, we use latest coating technology to achieve 5 OD (0.001%) out of band blocking. Each filter is individually tested and scanned to ensure that product quality meets our high-performance parameters. The end result is a filter that achieves excellent contrast but with a price-to-performance ratio that compares more favorably than similar premium filters in the market.
Features:
- Extra narrow 3nm bandwidth for superb contrast and ability to record the faintest H-alpha nebula detail
- > 5 OD (0.001%) (out of band blocking) @300-1000nm
- Steep spectral profile minimizes halos around bright stars
- Peak transmittance guaranteed >90% at the emission line 656.3nm to increase the contrast in the shortest possible imaging time
- 3nm Pro Narrowband filters are coated to the edge of the part and are edge blackened to minimize reflections and stray light
- A single substrate to eliminate internal reflections
- 3nm filters can be used with fast optical systems to f/3 with only slight loss of signal
- Parfocal with Antlia LRGB, SII and OIII filters (telescope optics need additional consideration)
- The Ha filter can be used with SII,OIII set of filters to achieve the impressive Hubble color palette
- Superior optical reliability reduces post image processing
- This filter is not suited to deep sky objects that do not contain Ha emissions
- NOT SAFE FOR USE AS A SOLAR FILTER
Specifications:
- Substrate: 1.25’’ mounted (2mm+/-0.05mm)
- Surface Quality: 60/40 (Refer to MIL-O-13830)
- 2 sides fine-optically polished to ensure accurate 1/4 wavefront
- 30 arc second parallelism
- Center-Wavelength of Antlia H-Alpha 3nm Pro filter: 656.3nm
- H-Alpha 656.3nm T>90%, 90% transmission at H-Alpha line 656.3nm
- > 5 OD(0.001%) @ 300-1000nm
- 2 sides multi-layers anti-reflection coating
- Single / Non-glued substrate
Filter Ring:
- 1.25’’ (M28.5x0.6)
- Ultra-thin filter cell to minimize vignetting
- Black anodized finish
- Laser engraving No fading
Not Recommended:
- Visual observation
- DO NOT LOOK AT THE SUN WITH ANTLIA FILTERS