Antlia Tribanda RGB Ultra 2" filter

Antlia Triband RGB Ultra Filter

It is designed for light pollution suppression for OSC and monochrome cameras. The spectral design selected the most substantial information in the RGB bands, which makes it possible for the Antlia Triband RGB Ultra filter to photograph more than 90% of deep sky objects, in addition to its excellent performance in emission nebulae, unlike other ultra-narrowband filters, it is able to capture galaxies, reflection nebulae and star clusters from Bortle 8 to Bortle 1 location presenting more balanced RGB colors in its images. In addition, it features a wide bandpass designed to cope with faster optics up to f/2 focal ratio.

The quantum efficiency of the B channel of current CMOS sensors is typically significantly lower than that of the R and G channels. The Antlia team's goal was to provide a more realistic color-balanced filter for astrophotography from light-polluted locations.

The problem of low blue wavelength efficiency becomes apparent when imaging reflection nebulae and blue stars. In CMOS sensors, blue wavelengths also contain the contribution of the more intense green spectrum, which affects the blue color balance. Many popular imaging objects contain reflection nebulae with faint blue hues, such as the central part of NGC 2264. Therefore, Antlia designed the Triband RGB Ultrafilter that not only retains the HSO emission signal, but also increases the amount of blue B-channel luminous flux. By improving the blue wavelength transmission, the photo color is better balanced and easier to handle in post-processing.

Application and performance:

♦ It is feasible to photograph galaxies, reflection nebulae and star clusters.
♦ Refined coating process makes Triband RGB Ultra filters with excellent halo suppression and improved signal-to-noise performance.
♦ It is specifically designed for balanced color transmission using Antlia's expertise in spectrum design.
♦ Balanced transmission allows for minimal color tint to broadband emission objects such as stars, galaxies and globular clusters.
♦ The Triband RGB Ultra can be used with almost all systems as fast as f/2 with minimal loss of efficiency or shifts in spectral response.
♦ When imaging LRGB with mono cameras, unless you wish to image LDN (dark nebulae), the Triband RGB Ultra can be used as a luminance filter substitute for objects such as nebulae and galaxies to improve contrast and signal-to-noise ratio.
♦ The Triband RGB Ultra is able to better isolate the H-alpha, [O III] and blue spectrum from background light pollution.
♦ For visual use, the Triband RGB Ultra filter ensures high transmittance of the HSO emission line and can be used to observe deep sky objects with large diameter telescopes.
♦ The filter provides excellent flexibility and compatibility with both OSC and monochromatic camera systems.
♦ It facilitates imaging of most astronomical objects using all optical configurations up to f/2 focal ratio.

Technical data:

Peak H-alpha transmission: >92% (at 656.3 nm)
Peak transmission [S II]: >92% (at 671.6 nm and 672.4 nm)
Peak transmission [O III]: >92% (at 495.9 nm and 500.7 nm)
Peak transmission [N II]: >92% (at 658.3 nm and 654.8 nm)
Blocking: ≥OD4 at 300-1100 nm
Filter thickness: 2 mm +/-0.05 mm
Focal ratio: Up to f/2