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This is an Astronomik 6nm H-alpha filter in excellent condition. It is clean, with no marks or dust on the optics. This is the 6nm version - which means that the bandwidth pass is very narrow, tighter, for better, cleaner data.
This does not include a plastic case or jewel box.
This H-alpha Filter is suitable for imaging of Hydrogen nebulas from observation sites with light pollution and from dark sites as well. The contrast between an object glowing at 656nm and the background is increased enormous!
Due to the combination of the narrow bandwidth of 6nm and the high transmission of typically 96% the filter gives you an enormous contrast boost, as all unwanted light from other wavelengths than 656nm is blocked from UV up to the IR. This results in an extremely dark background.
The FWHM of 6nm is matched to give you optimal performance with CCD and CMOS sensors with a very low dark current! The 6nm filter is the best choice if you are observing from a heavily light polluted site or if you are imaging faint objects in star crowded regions of the Milky Way.
Due to the new MFR coating technique you may use one single filter on all instruments up to f/4 without a significant reduction in performance.
Der Astronomik H-alpha filter MUST NOT BE USED for solar observation!
Technical data of the filter:
- Guaranteed Transmission of more than 90% at the H-alpha Line (656 nm)
- Typical Transmission of 96% at the H-alpha Line (656 nm)
- Full-Width-Half Maximum (FWHM): 6nm
- perfect blocking of unwanted light from UV up to the IR
- parfocal with all Astronomik filters
- MFR Coating technique: Usable with all optics up to f/4
- Thickness of 1mm
- Not sensitive to moisture, scratch resistant, not aging
- optically polished substrate, striae-free and free of residual stresses
- High quality storage box
Imaging with Narrowband-Emission line Filters
If you have to observe from light polluted sites (like most of us...), imaging with Narrowband-Emission line filters is the best way to take great images, as all kind of light pollution can be blocked very effective! Normally an H-alpha filter should be your first step into this amazing field of astrophotography! With an Narrowband H-alpha filter you will be able to take deep and contrasty images even with very heavy light pollution or with the full moon high up in the sky!
If you look at other astrophotos, an H-alpha is the best choice for all nebulas glowing red! An OIII filters expands your imaging possibilities, as you are able to image all greenish/blueish structures. Planetary nebulas and star forming regions are great targets! The SII filters completes your HSO-set of filters. With these three filters you are able to process your images like the ones from the Hubble space telescope!
Operation of the filter:
The filter blocks all unwanted light from artificial light-pollution, natural airglow and moonlight. Especially light from High- and Low-Pressure Sodium and mercury lights and all lines of natural airglow are 100% blocked. The filter increases the contrast between the sky-background and objects glowing at the xx line at xy nm.
Tips and Hints for more applications:
Using the H-alpha-CCD filter together with OIII-CCD and SII-CCD filters you make produce false-color emission line images (HSO) in the same way as the Hubble-Space telescope. This is possible even from heavily light polluted sites!
All Astronomik Filters are perfect for modern cameras, including both CMOS and CCD based cameras, allowing you to capture the very best images possible with your instruments. Sharpness, contrast and the absence of any reflections is guaranteed.
Each and every Astronomik filter has to pass a complex quality control process before being suitable for delivery to our customers. Each and every emission line filter is measured with a high-end Perkin-Elmer spectral-photometer to make sure that every single filter is up to the specifications published on our website.