1. Antlia ALP-T Dualband 5nm Ha & OIII Filter

The Antlia ALP-T dual band 5nm Ha&OIII filter is a dual line-pass filter which was designed to be used primarily with one-shot color (OSC) cameras such as DSLR’s and astronomical OSC cameras. It can also be used as a narrowband filter for monochrome cameras to save imaging time. The advanced multi-coatings on Antlia ALP-T ultra dual band filter effectively isolates the red Ha and the blue-green OIII lines light from emission nebulae, with almost total suppression of optical density (OD)4.5 on unwanted wavelengths from light pollution, moonlight, and airglow. The result is that our ALP-T dual band 5nm filter creates a superior signal-to-noise ratio and better contrast in your images.
The filter enables the capture of the two main emission nebulae bands at the same time, whilst suppressing unwanted light pollution. It enables you to capture cleaner data and reduces the post processing efforts to isolate faint details from the background light pollution.

Application and performance:

• Passes OIII at 500.7nm and H-alpha at 656.3nm

• Captures two key emission wavebands—red and blue-green—simultaneously

• Features an ultra-narrow 5nm FWHM design, allowing longer exposures and capturing fine nebular details

• Designed primarily for colour cameras to collect cleaner data

• Also functions as a luminance filter for monochrome cameras, saving imaging time

• Works best when paired with the ALP-T Dual Band SII & H-beta filter, enabling four-channel imaging (Ha, OIII, SII, H-beta) with improved signal-to-noise ratio and channel separation

• Suppresses unwanted wavelengths with OD4.5 optical density, boosting signal-to-noise for clearer, high-contrast images

Spectrum Curve:

2. Antlia ALP-T Dualband 5nm SII & H-beta Filter

The ALP-T Dualband 3.5nm SII & H-beta filter complements the Ha & OIII version, giving astrophotographers the ability to capture additional emission lines in deep-sky objects. It transmits the deep red Sulphur-II line at 672.4nm and the blue Hydrogen-beta line at 486.1nm. Engineered primarily for colour cameras, this filter enhances your imaging by delivering higher signal-to-noise ratio and improved contrast. The narrow 3.5nm FWHM and OD4.5 blocking efficiently suppress light pollution, moonlight, and airglow, allowing only the SII and H-beta signals to pass.

This filter is a valuable addition to the Ha & OIII setup, enabling OSC users to produce narrowband and false-colour images with greater flexibility. When paired with the Ha & OIII filter, it allows you to capture four distinct spectral channels (Ha, OIII, SII, and H-beta), which can then be separated and recombined in post-processing. This combination lets you build custom colour palettes, enhance contrast, and reveal finer details within nebulae that standard RGB imaging often misses.

As with the Ha & OIII filter, the SII & H-beta version features Antlia’s advanced multi-coatings. These coatings precisely isolate the desired wavelengths and suppress unwanted light with OD4.5 performance, ensuring consistent results across different sky conditions. Whether imaging in light-polluted urban environments or under dark rural skies, both filters maintain superior contrast and deliver cleaner data for high-quality astrophotography.

Together, the ALP-T Dualband Ha & OIII and SII & H-beta filters unlock full narrowband imaging potential for OSC users. They provide the tools needed to create striking, detailed images of the night sky with minimal interference and maximum flexibility.

Application and Performance:

• Passes Sulphur-II (SII) at 672.4nm and Hydrogen-beta (H-beta) at 486.1nm

• Captures two key emission wavebands—deep red and blue—simultaneously

• Features an ultra-narrow 3.5nm FWHM design for longer exposures and detailed nebula capture

• Designed primarily for colour cameras to record cleaner data

• Also works as a luminance filter for monochrome cameras, reducing imaging time

• Recommended for use with the ALP-T Dual Band Ha & OIII filter to achieve better signal-to-noise ratio (SNR) and improved channel separation across Ha, OIII, SII, and H-beta

• Suppresses unwanted wavelengths with OD4.5 optical density, enhancing SNR

• Blocks near-infrared (NIR) wavelengths up to 1100nm to prevent signal contamination

• Maintains spectral accuracy with a flat-top, moderate bandpass that reduces spectral shifts

• Delivers best performance with optics slower than f/4; for faster systems, use the pre-shifted highspeed version

• Uses Ion Gun Assisted Deposition to apply double-sided multi-layer coatings on polished substrates for consistent and precise light pollution suppression

• Features anti-reflective halo suppression coatings to minimise halos and internal reflections

• Effectively suppresses artificial lighting across Bortle scale 1 to Bortle scale 8 conditions

• Includes blackened edges (on unmounted versions) to reduce internal reflections

• Built with Antlia’s trusted coating technology for outstanding durability

• Performs exceptionally with both colour and monochrome cameras, helping to save imaging time

Spectrum Curve:

Filter Ring:

2” (M48*0.75)

Ultra-thin filter cell to minimize vignetting by maximize possible clear aperture

Black Anodized Finish

Laser Engraving No Fading

Not Recommended:

Solar imaging

Night visual observation