The Antlia H-alpha EDGE narrowband filter features a 4.5nm Full Width at Half Maximum (FWHM) bandpass, striking a balance between contrast and signal strength. By incorporating OD5 optical density suppression for unwanted wavelengths—alongside the high transmittance performance seen in the 3nm Pro series—these filters deliver excellent signal-to-noise ratio (SNR) and enhanced contrast in your images.

Engineered for high efficiency, the H-alpha 4.5nm EDGE filter transmits over 90% of light at the 656.3nm emission line, helping you capture even the faintest details in H-alpha nebulae.

Unlike broader narrowband filters that suffer significant transmission loss due to centre wavelength (CWL) shift, Antlia’s EDGE filters maintain T>90% within ±1nm of the central wavelength. This consistency ensures strong performance across a wide range of telescope configurations.

Blue-shift testing confirms that the 4.5nm EDGE filter works exceptionally well with both long focal ratio systems and fast optics, including setups as fast as f/3, with minimal signal loss—making it a reliable choice for astrophotographers using high-speed imaging systems.

Application and Performance:

• Delivers high transmittance with a narrow 4.5nm bandwidth to enhance contrast and isolate H-alpha emissions

• Features a steep spectral curve that helps suppress halos around bright stars

• Built from a single optical substrate to reduce internal reflections and improve image clarity

• Ideal for capturing H-alpha-rich targets such as emission nebulae, planetary nebulae, Wolf-Rayet nebulae, and supernova remnants

• Performs well under both light-polluted skies and dark-sky conditions

• Allows extended imaging sessions during bright moon phases by effectively blocking unwanted light

• Supports fast optical systems down to f/3 with minimal loss of signal, making it suitable for setups like RASA and HyperStar

• All unmounted Antlia EDGE filters are edge-blackened to eliminate internal reflections from stray light

• Offers high optical reliability, reducing the need for heavy post-processing

• Recommended for use only with deep-sky objects that emit in the H-alpha wavelength

The filter ring features a 2″ (M48×0.75) thread. Its ultra-thin filter cell maximises the clear aperture and helps minimise vignetting in fast optical systems. A durable black anodised finish protects the housing, while laser-engraved markings ensure long-term visibility without fading.

Important: This filter isn’t suitable for solar imaging or night-time visual observation.

Warning: Never look directly at the Sun using this filter. Ignoring this safety warning can result in serious and permanent eye damage.

Antlia also offers dual narrowband filters designed specifically for one-shot colour (OSC) cameras. These include the ALP-T Dualband Ha&OIII 3nm and the SII&Hb 3.5nm filters. When used together, they enable the capture of narrow-band spectral data across four channels—H-alpha, OIII, SII, and H-beta. You can separate and recombine these channels during post-processing to create a wide range of colour palettes. This flexibility allows you to boost luminance contrast in RGB-balanced images or produce false-colour combinations such as H-O-Hb, S-H-O, H-S-OHb, and H-O-O to suit your creative and scientific goals.