Now you can get BOTH the 3.5nm DualBand Ha Oiii and the DualBand 3.5nm Sii Oiii filters together for a lower price!

By using both filters individually you get twice the Oiii data you would otherwise, plus separation of Ha and Sii Channels, so you can now do proper SHO Hubble pallette style imaging with a colour camera!

In the box:

• 3.5nm DualBand Ha Oiii ULTRA filter with individual spectrographic test report
• 3.5nm DualBand Sii Oiii ULTRA filter with individual spectrographic test report

Altair Dual Band filters allow imaging in bright moonlight and extreme light pollution as in major city centre such as London or Tokyo, with a colour CMOS camera - or in dark conditions if you want total control over your channels.

As a set, these filters transmit the Ha, Sii and Oiii light from emission nebulae, with almost total suppression of unwanted light, with OD6 or better (~0.0001%) over the majority of unwanted visual wavelengths.

In a process pioneered by Altair, each individual filter has an individual test report, unique to that particular filter (not a blanket test report for the whole batch like other manufacturers). Please note that these are accurate tests on a professional spectrograph at 0.1nm resolution.

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 signal vs. background performance.

Altair DualBand 3.5nm Filter 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 Oiii data, whilst obtaining Sii to complement the Altair Ha Oiii DualBand filter.
• Extremely steep bandpass yields maximum contrast in extreme light pollution: 3.5nm FHWM.
• Halo suppression anti-reflective coating.
• Can be used with One Shot Colour (OSC) CMOS and also with 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. More info about light pollution filter performance and focal ratio here.
• The 2" filter has standard M48x0.75mm thread, and fits inside the Altair Magnetic Filter holders, standard 2" filter wheels, plus the Altair Canon / Nikon DSLR lens to astro CMOS adaptors.

Altair 3.5nm DualBand Sii Oiii ULTRA Filter Specifications:

• 1st band, Oiii CWL 500.7nm FWHM tolerance ~0.2nm, T% 90-95%
• 2nd band, Sii CWL 671.6nm FWHM tolerance ~0.2nm T% 90-95%

Altair 3.5nm DualBand Ha Oiii ULTRA Filter Specifications:

• 1st band, Oiii CWL 500.7nm FWHM tolerance ~0.2nm, T% 09%~95%
• 2nd band, Ha CWL 656.3nm FWHM tolerance ~0.2nm T% 90%~95%

Both filters shared specifications: 

• Parfocal 1.85mm thick optical glass with 30 arc sec parallelism.
• Individual spectrographic test report for guaranteed quality and performance
• OD6 Blocking (0.0001%) over the majority of unwanted wavelengths
• Si02 "hard" overcoat with UVIR Block and Anti-Reflection Coating for durability.

Scope of delivery:

2x Filter HA, OIII und SII, OIII