Ha Oiii DualBand 6nm CERTIFIED CMOS Filter & Test Report 2"

Altair Dual-Band ULTRA Ha / Oii narrowband filter with a tight 6nm FWHM Bandpass. 

Individual spectrographic test report included with each filter - another Altair first.
Available in 1.25" or 2" standard astronomy filter sizes, please choose size when ordering.

Altair V2 coatings are very effective for LED light pollution, with a deeper blocking factor of OD>6 for wavelengths below 440nm, and OD4.5 for the visual range.

This is the filter for imaging in moonlight or light pollution with a colour CMOS camera - or even in dark-sky conditions if you want total isolation and control over your channels, narrowband-style.

In a process pioneered by Altair, each individual filter in our certified range has an individual spectrographic test report with 0.1nm 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 5nm FWHM but which actually have 6-7nm FWHM, and which have generic test reports.

The DualBand Ha/Oiii filter transmits only the Ha 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. 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.

Here's an overview of wavelengths transmitted by DualBand filters:

Altair DualBand 6nm Filter Features:

• Capture the two main emission nebulae bands at the same time, whilst suppressing light pollution, moonlight, and airglow.
• Acquire more data in less time, opening up your imaging window, even into the summer months when it isn't quite dark.
• If you have the 6nm Ha/Sii Ultra filter and the Sii/Ha version, you can capture twice the Oiii data in each imaging session and combine them for true SHO Hubble style imaging with a colour camera!
• Extremely steep bandpass yields maximum contrast in extreme light pollution: 6nm FHWM centred on 500.7nm Oiii wavelength, and 5.5nm FHWM centred on the 656.28nm Ha wavelength.
• Halo suppression anti-reflective coating.
• 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 the ultimate in contrast.
• Best performance at focal ratios at F4.8 or slower, however can be used as fast as F3.6, with minimal contrast impact (conservative estimate - faster may be possible). Like any dichroic filter, contrast increases as focal ratio number increases. More info about light pollution filter performance and focal ratio here.
• Available in 1.25" or 2" standard astronomy filter sizes. The filters have standard Astronomy compatible filter threads, and fit inside the Altair Magnetic Filter holders (with appropriate slider), and standard astronomy filter wheels. Choose the 2" version for use with the Altair Canon / Nikon DSLR lens to astro CMOS adaptors. For Hypercam 183C and 533C or 533M, 585C and smaller sensors choose the 1.25" filter. For larger sensors choose the 2" version.

Altair 6nm DualBand ULTRA Filter Specifications:

• *1st band, Oiii CWL 500.7nm FWHM 6nm ~1nm tolerance , T% 93% 1% Tolerance.
• *2nd band, Ha CWL 656.28nm FWHM 5.5nm ~1nm tolerance, T% 93% 1% Tolerance.
• OD4/5 Blocking (0.01%~0.001%) over the majority of unwanted wavelengths
• 1.85mm thick optical glass with 30 arc sec parallelism. Parfocal with other Altair filters.
• Si02 "hard" overcoat with UVIR Block and Anti-Reflection Coating for durability.

Size: 2"