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.

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.

Scope of Delivery:

• Altair 1.25" Ha Oiii DualBand 6nm CERTIFIED CMOS Filter & test report