The Askar 6nm Duo-narrowband Filter (OIII & SII) has ultra-high transmittance over 90% at its centre wavelength (500.7nm and 656.3nm) and can effectively eliminate the influence of light pollution.
Even in locations seriously affected by light pollution, images taken with the Askar 6nm Duo-narrowband Filter are still of very high quality.
The Askar 6nm Duo-narrowband Filter (OIII & SII) is ideal for photographing emission nebulae, planetary nebulae or supernova remnants.
The narrow bandwidth of the filter effectively blocks out the effects of light pollution or other distracting factors such as night glow.
Currently available as a 2" Mounted filter (other sizes planned).
Colour Magic 6nm Duo-narrowband Filter (OIII & SII)
While most of the commercially available duo-narrowband filters for deep-sky astrophotography are in the Ha and OIII bands, ASKAR offers another structure: SII & OIII.
When shooting deep-sky galaxies with colour cameras, a duo-narrowband filter in the Ha and OIII bands is often used; whereas with a mono camera, a narrowband filter in the Ha, SII and OIII bands is often used, leaving users with colour cameras missing one band of nebula detail. This can be compensated by using the SII and OIII duo-narrowband filters mentioned above.
The Askar 6nm Duo-narrowband Filter (OIII & SII) has ultra-high transmittance over 90% at its centre wavelength (500.7nm and 671nm). The Askar 6nm Duo-narrowband Filter (OIII & SII) can effectively eliminate the influence of light pollution. Even if you are in an area seriously affected by light pollution, the pictures taken with the Askar 6nm Duo-narrowband Filter (OIII & SII) are still of very good. quality. It is so practical and efficient that you can get astronomical images of high quality with just one duo-narrowband filter and an ordinary astronomical colour camera.
The Askar 6nm Duo-narrowband Filter (OIII & SII) is ideal for photographing emission nebulae, planetary nebulae or supernova remnants, and has a very high transmittance at the central wavelength. The narrow bandwidth of the filter effectively blocks out the effects of light pollution or other distracting factors such as night glow.
Specifications
- 6nm Duo-narrowband Filter (OIII & SII) 2”
- FWHM: 6nm
- CWL: 500.7nm & 671nm
- Peak transmittance：90%
- Thickness：1.85 ± 0.05mm
- Barrier property：≥OD5 @ 200-1100nm
- Surface finish：60/40
- Parallelism：30”
Further Notes
In addition to the common Dual Band Hα+OIII filters, Askar has also designed this SII+OIII Dual Band filter which is especially suitable for use with Dual Band Hα+OIII filters.
When shooting data through both dual band filters (Duo Band SII+OIII and Duo Band Ha+OIII filter) and a colour camera, users will have remarkable results.
Usually, in astrophotography, the Hα signal-to-noise ratio is stronger while the OIII is relatively weak. As our two duo-narrowband filters are Hα+OIII and SII+OIII, the combination can balance the signal-to-noise ratio of each channel when shooting data, and after image processing, it can achieve an excellent result which is almost as good as shooting with a combination of three narrowband filters and mono camera.
Askar have named the Hα+OIII 2" 6nm duo-narrowband filter "D1" and the SII+OIII filter "D2". They are now available as a set in 2" Mounted format only.
Here is a link detailing how to process D1 and D2 Data in Pixinsight
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