Antlia 3nm Pro - 2″ NII filter

Antlia NII 3nm Pro filter

Interferential Filter for Astrophotography

The Antlia NII 3nm Pro filter optimizes the FWHM to a bandwidth of 3nm. By reducing this band, the filter significantly improves the contrast of emission targets by attenuating background signals. It is designed to achieve a transmission of 88% at 654.8nm, guaranteeing a strong signal and well-defined nebular structures.

Out-of-band rejection is specified at OD5 (0.001%), ensuring an excellent signal-to-noise ratio (SNR) and effective cut-off of unwanted wavelengths. This filter is specially designed to minimize halos around bright stars, thanks to its clean spectral profile.

Key features and applications

• High transmission and narrow bandwidth for maximum contrast
• Steep spectral profile reduces stellar halos
• One-piece, glueless optical substrate to prevent internal reflections
• Target: NII emission nebulae
• Can be used on polluted sites and in deep skies
• Extends imaging sessions even in the presence of the Moon
• Compatible with high-speed lenses up to f/3 without significant loss of performance
• Unmounted filters are blackened at the edges to eliminate reflections.
• Excellent optical reliability, reducing post-processing corrections
• Designed specifically for NII-emitting celestial objects

Technical specifications

Spectral curve

Filter ring

• 2'' format (M48x0.75)
• Ultra-thin cell to minimize vignetting
• Black anodized finish
• Tamper-proof laser engraving

Not recommended for :

• Solar observation
• Visual observation at night

Warning:

NEVER LOOK DIRECTLY AT THE SUN WITH THIS FILTER. Serious eye damage may occur.