Antlia designed the 7nm Prime narrowband filters with a precise 7nm FWHM (Full Width at Half Maximum) bandpass. This strikes a strong balance between signal transmission and background suppression. Antlia uses the same advanced optical coatings found in their 3nm Pro series. As a result, these filters deliver high contrast and excellent signal-to-noise ratio—even in tough imaging conditions.

Each filter transmits 90% at its central wavelength: SII at 671.6nm, H-alpha at 656.3nm, and OIII at 500.7nm. This high transmittance helps you capture faint emission nebulae, planetary nebulae, Wolf-Rayet regions, and supernova remnants. The H-alpha filter’s 7nm bandpass also covers nearby NII lines at 654.8nm and 658.3nm. You’ll gain extra structural detail in your images.

Out-of-band blocking is rated at OD4 (0.01%). This cuts unwanted light and prevents interference from other wavelengths. A steep spectral profile reduces halos around bright stars. You get cleaner, sharper frames as a result.

Antlia built the 7nm Prime series for a wide range of telescopes. It works with fast systems down to f/2 without losing signal. Whether you’re imaging under light-polluted skies or at a dark site, these filters deliver consistent, high-quality performance.

Application and Performance:

• Features 7nm bandpass, 36mm unmounted narrowband filters

• Delivers 90% transmittance at key emission wavelengths: SII (671.6nm), H-alpha (656.3nm), and OIII (500.7nm)

• Supports fast optical systems down to f/2 with minimal signal loss—ideal for wide-field setups

• Uses a steep spectral profile to reduce halos around bright stars and enhance contrast

• Utilizes a single glass substrate to eliminate internal reflections and improve image clarity

• Targets narrowband deep-sky objects including emission nebulae, planetary nebulae, Wolf-Rayet regions, and supernova remnants

• Performs reliably under both dark skies and light-polluted environments

• Incorporates edge-blackening to block stray light and minimize internal reflections

• Maintains a precise thickness of 2mm ± 0.05mm for 1.25″, 2″, 31mm, and 36mm unmounted filters

• Provides 3mm ± 0.05mm thickness for 50mm and 50x50mm unmounted filters

• Offers fine optical polishing on both sides for enhanced flatness and imaging precision

Not recommended for:

• Solar imaging

• Visual observation at night