Antlia designed the ALP-T Dual Band 5nm Highspeed filters specifically for fast optical systems, optimizing their performance by slightly shifting the passband and central wavelengths. When used with fast optics between f/2.2 and f/3.6, these highspeed filters deliver noticeably stronger signal and greater contrast in nebula imaging compared to the standard version.

If your telescope operates at slower focal ratios (f/3.6 and above), the standard ALP-T Dual Band 5nm filter remains the recommended choice. For setups faster than f/2.2, the highspeed version offers the best possible performance.

Computer simulations show that narrowband filters experience a blue shift at focal ratios faster than f/2, potentially reducing transmission at emission wavelengths by 15–20%. Despite this shift, real-world results from users confirm that the Antlia ALP-T Highspeed filters still provide excellent contrast for emission nebulae and minimize halos—even under extreme optical conditions.

Both standard and highspeed versions are priced equally, offering high-speed optics users exceptional value. Antlia ensures product quality by individually inspecting and measuring each filter using Agilent Cary spectrophotometers with a resolution up to 0.2nm, guaranteeing high consistency and reliability.

The ALP-T Dual Band 5nm filter uses a dual line-pass design that targets the H-alpha (656.3nm) and OIII (500.7nm) emission lines. It’s ideal for one-shot color (OSC) cameras, such as DSLRs and dedicated astronomy cameras, and also serves as a time-saving narrowband option for monochrome setups.

Advanced multi-coatings effectively isolate the key emission lines while suppressing unwanted light with OD4.5 optical density. This results in higher signal-to-noise ratios and better overall image contrast.

By capturing both H-alpha and OIII emissions simultaneously, the ALP-T filter reduces the impact of light pollution and streamlines post-processing. You’ll gather cleaner data and reveal faint nebular details with less effort.

Application and Performance:

• Antlia designed this filter specifically for fast astronomy optics, especially those with focal ratios from f/2.2 to f/3.6.

• It works seamlessly with DSLR, CMOS, and CCD color cameras to capture high-contrast deep-sky images.

• The filter suppresses unwanted wavelengths with OD4.5 optical density, boosting your signal-to-noise ratio.

• Its ultra-steep bandpass edges help minimize internal reflections and maintain image clarity.

• The flat-top, moderate bandpass profile reduces spectrum shift while preserving accurate color balance.

• Antlia applies Ion Gun Assisted Deposition coatings on a double-sided polished substrate, ensuring consistency and precision in light pollution suppression.

• It effectively blocks artificial lighting across a wide range of sky conditions, from Bortle 1 to Bortle 8.

• The filter also blocks near-infrared (NIR) light up to 1050nm, preventing unwanted signal contamination.

Spectrum Curve:

Filter Ring:

2” (M48*0.75)

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

Black Anodised Finish

Laser Engraving No Fading

Not Recommended:

Solar imaging

Night visual observation