Altair 2" Ha OIII 4 nm DualBand CMOS Filter with test report

Altair 2" H-alpha / O-III 4 nm CMOS DualBand Filter with test report

The Altair Dual-Band ULTRA H-alpha / [O III] nebula filter comes with a high resolution spectrographic test report.

Designed for imaging in extreme light pollution, e.g. in a major city, with a colour CMOS camera.

This filter transmits only the H-alpha and [O III] light from emission nebulae, with almost total suppression of unwanted light, with OD6 (0.0001%) over the majority of unwanted visual wavelengths for ultimate contrast.

In a process pioneered by Altair, each individual filter in their certified range has an individual spectrographic test report with 0.1 nm true resolution, unique to that particular filter. This is not a simulation, nor the overly optimistic marketing you tend to get with foreign filters - such as those advertised at 5 nm FWHM but which actually have 6-7 nm FWHM, and which have generic test reports.

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 QuadBand filters, now they have the DualBand Ultra for the most extreme light pollution suppression.

Altair DualBand 4 nm 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. Capture twice the amount of [O III] data if you also use the Altair [O III]/[S II] DualBand filter.

Extremely steep bandpass yields maximum contrast in extreme light pollution: 4 nm FHWM centred on 500.7 nm [O III] wavelength, and 4 nm FHWM centred on the 656.3 nm H-alpha wavelength.

Halo suppression anti-reflective coating.

Can be used with One Shot Colour (OSC) CMOS or monochrome astronomical cameras for luminance data.

Includes UV/IR blocking for both modified and un-modified DSLR cameras.

Best performance at focal ratios as fast as f/4.0, optimised at f/4.8 or slower, with contrast increasing as focal ratio increases. Faster than f/3.5 requires an Altair pre-shifted filter (please get in touch for more info).

The 2" filter has standard M48x0.75 thread, and fits inside the Altair Magnetic Filter holders, plus the Altair Canon / Nikon DSLR lens to astro CMOS adaptors.

How do OSC narrowband filters work?

Altair OSC narrowband filters work by isolating the primary nebulae emission zones in the red and blue 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 more convenient with one filter, but processing is easy too, thanks to the wide separation of the green/blue and red "zones". Light pollution control is extremely effective and even LED light pollution is significantly reduced.

- Filter
- Protective box

Safety informations: PDF Download