Altair DualBand Ultra 4nm Certified CMOS Filter 2 Inch & test report

Product Description

Altair Dual-Band ULTRA Oiii / Ha nebula filter with high resolution spectrographic test report. For imaging in extreme light pollution, E.g. in a major city, with a colour CMOS camera. This filter transmits only the H and Oiii light from emission nebulae, with almost total suppression of unwanted light, with OD4/5 (0.01%~0.001%) over the majority of unwanted visual wavelengths.

Certification
Each individual filter has a serial number and comes with corresponding test certificate showing the bandpass, tested on a high resolution spectrograph. These are limited in quantity, and are the highest specification filter available at this time. NOTE: Each filter has an INDIVIDUAL test report unique to that particular filter.

Narrowband Bi-Colour imaging is a growing new trend in astrophotography, especially popular in light polluted areas, or bright moonlight. First Altair brought you the TriBand and Quad Band filters, now we have the DualBand Ultra for the most extreme light pollution suppression.

Altair DualBand 4nm Filter Product Features:
Capture the two main emission nebulae bands at the same time, whilst suppressing light pollution, moonlight, and airglow.
More data in less time, opening up your imaging window, even into the summer months when it isn't quite dark yet.
Extremely steep bandpass yields maximum contrast in extreme light pollution: 4nm FHWM centred on 500.7nm Oiii wavelength, and 4nm FHWM centred on the 656.3nm Ha wavelength.
Can be used with One Shot Colour (OSC) CMOS or mono astronomical cameras for luminance data.
Includes UVIR blocking for both modified and un-modified DSLR cameras, plus an anti-reflection coating for halo suppression.
Best performance at focal ratios as fast as F4.8, with contrast increasing as focal ratio increases, so these filters work great with f6 to f8 refractors used for imaging..

Sensitive OSC or "One Shot Colour" CMOS cameras like the Altair Hypercam 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 these filters as a "super luminance filter" for imaging nebulae with Mono cameras.