Altair Sii Oiii DualBand ULTRA 3.5nm CERTIFIED CMOS Filter 2" w 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.

This filter transmits only the 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.
• Using the Dual Band COMBO filter set you can 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. 
• 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
• Average OD6 Blocking (0.0001%) over the majority of unwanted wavelengths.
• Si02 "hard" overcoat with UVIR Block and Anti-Reflection Coating for durability.

Q: How to 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 LED light is also significantly reduced.

Q: What does "DualBand" mean?

There are 3 types of OSC line filters in the Altair range:

1. Dual-Band - the allowing only the thinnest peaks of Ha 656.3nm (or Sii 671.6nm) and 500.7nm Oiii light from emission nebulae through. (Recommended for extreme light pollution in the worst possible conditions).
2. Tri-Band - combines Ha into a red zone, and H-beta + Oiii into a green/blue zone. (For urban light pollution).
3. Quad Band - combines Sii AND Ha into a red zone, and H-beta + Oiii into a green/blue zone. (For suburban / moderate light pollution).

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.

USA customers can also buy this filter from Astroworld in New York, APM Germany and Pierro Astro in France.

PLEASE NOTE: Demand for this product is very high and they are made in small batches. We sometimes temporarily suspend order to allow production to catch up. When we catch up with backorders we will re-enable ordering. We apologize for any inconvenience.

Altair Astro and Authorised Resellers reserve the right to change the product specification and price without notice.

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