Product description Altair QuadBand is the new trend in light pollution filters for deep-sky imaging of emission nebulae with colour CMOS, CCD, and DSLR cameras. Altair V2 Filter Technology produces even better blocking of unwanted wavelengths, higher transmission, and no halos. The result is a better signal to noise ratio for imaging emission nebulae with a DSLR or CMOS Astro camera. The 35nm passband not only makes the QuadBand V2 compatible with fast focal ratio lenses and telescopes, but also allows visual use with a relatively small telescope in urban locations. Brighter emission nebulae can be observed in urban conditions with a darker background. This is the new QuadBand V2 Coating technology which includes: Anti-Halo coating on both surfaces to reduce reflection artefacts from reducers and camera lenses. Increased blocking of UV, IR and unwanted visual range wavelengths. UV OD7 (T0.00001%) Visual OD5 (T0.001%) and IR OD4 (T0.01%) for the ultimate in skyglow blocking. Higher transmission % of desired wavelengths Ttop 95% (Average 5% higher transmission of desired wavelengths). Ha and Oiii wavelengths at 35nm FWHM for with less tail-off to reduce unwanted light pollution. It's even compatible with fast scopes, like Altair F6 refractors which operate at F4.8 with reducers, and the F2 Celestron RASA and Hyperstar. Includes UVIR blocking for both modified and un-modified DSLR cameras, plus an anti-reflection coating to reduce halos as much as possible. Narrowband Bi-Colour imaging is a growing new trend in astrophotography, especially popular in light polluted areas, or for imaging in rural areas in moonlight. Now you can capture the two main emission nebulae bands at the same time, whilst suppressing light pollution, moonlight, and airglow. Capture more data in less time, and open up your imaging time window - even into the summer months. Altair QuadBand light pollution filters work by isolating the primary nebulae emission zones in the red and blue/green wavelengths, and separating them into two main "zones" with a wide separation for easy capture with a colour camera - all in one exposure! Not only is capture very convenient, but processing is easy too, thanks to the wide separation of the green/blue and red "zones". Light pollution control is extremely effective and LED light is also significantly reduced, thanks to the effects of Rayleigh scattering. Sensitive OSC or "One Shot Colour" CMOS cameras like the #Hypercam183C capture these wavelengths very efficiently, and allow them through the Bayer matrix. The filters also work with DSLRs (APS-C sensor size modified cameras are best, but normal ones will also work). When you have the complete stack of exposures, processing is relatively easy because of the large separation in colour. You can also use the Quad band and Tri-Band filters as a "super luminance filter" for imaging nebulae with Mono cameras. A quick overview of the Altair Filter family: QuadBand Filter - combines Sii AND Ha into a red zone, and H-beta + Oiii into a green/blue zone. (Recommended for moderate light pollution and skyglow, used with colour cameras). TriBand Filter - combines Ha into a red zone, and H-beta + Oiii into a green/blue zone. (Recommended for higher light pollution, used with colour cameras). DualBand Filter - separates Ha and Sii even more distinctly with even deeper blocking. (Recommended for severe light pollution such as within built-up areas such as cities. Used with colour cameras). NarrowBand mono camera filter - these isolate single bands, so you only capture one wavelength per filter such as Oiii or Ha or Sii, and they are mostly used with mono B&W astronomy cameras. Separate sets of exposures are required with each filter. Filter Specifications: QuadBand OSC filter CWL: 1st band, CWL495nm FWHM35nm 2nd band, CWL 660nm FWHM 35nm 1.85mm thick optical glass with 30 arc sec parallelism. UVIR Block and Anti-Reflection Coating. Delivered with: Filter

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