Photographic Astronomik MFR Narrowband-Emissionline OIII-CCD filter with 12 nm FWHM
This Astronomik OIII-CCD Filter is suitable for imaging of OIII nebulas from observation sites with light pollution and from dark sites as well. The contrast between an object glowing at 501 nm and the background is increased enormous!
Due to the combination of the narrow bandwidth of 12 nm and the high transmission of typically 96 % the filter gives you an contrast boost, as all unwanted light from other wavelengths than 501 nm is blocked from UV up to IR. This results in an very dark background compared with any filters with a higher bandwidth.
The FWHM of 12 nm is optimized for typical DSLR cameras with CMOS sensors and CCD cameras with a normal / high dark current: With these cameras the background signal in images taken from heavily light polluted sites is dominated by the dark current of the sensor, not by fluy coming from light pollution. In this case a further reduction of FWHM does not improve the image, as the background will not get darker. Compared to the 6 nm filters you have more stars in the field of view which gives you more guiding stars when working with an integrated / dual guiding chip!Due to the new MFR coating technique you may use one single filter on all instruments up to f/3 without a significant reduction in performance.
The Astronomik H-Alpha filter MUST NOT BE USED for solar observation!
Technical data of the filter:
- Guaranteed Transmission of more than 90 % at the OIII Line (501 nm)
- Typical Transmission of 96 % at the OIII Line (501 nm)
- Full-Width-Half Maximium (FWHM): 12 nm
- 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/3
- Thickness of 1 mm
- 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-Emissionline Filters
If you have to observe from light polluted sites (like most of us...), imaging with Narrowband-Emissionline filters is the best way to take great images, as all kind of light pollution can be blocked very effective! Normaly 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 filter 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 you HSO - set of filters. With these three filters you are able to process your images like the ones from the Hubble space telescope!
The H-Beta filter is not available in a 6 nm version, as this filter has nearly no meaningfull application.
Operation of the filter:
The filter blocks all unwanted light from artifical 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.
Tipps and Hints for more applications:
Using the OIII filter together with H-alpha 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.
If want to image faint objects in starcrowded regions of the milkyway, probably using short focal lengths, the 6 nm filter will be the better choice, as the number of stars is reduced by a factor of 2. You should even take the 6 nm version if you have a camera with a low thermal current or if you have to observe from a really heavily light polluted site.
Astronomik OIII-CCD Filter with 12 nm FWHM in 1,25".