Antlia ALP-T Dualband 3nm Ha and OIII filter

Antlia ALP-T Dualband 3nm Ha&OIII filter

The Antlia ALP-T Dualband 3nm Ha&OIII filter is an ultra-narrow dual-band filter that transmits the red H-alpha (656.3 nm) and blue-green OIII (500.7 nm) lines. Designed primarily for color cameras (OSC), it significantly improves the signal-to-noise ratio in deep-sky astrophotography, even under light pollution or moonlight.

Key features

• Simultaneous transmission of H-alpha (656.3nm) and OIII (500.7nm) lines
• Ultra-narrow bandwidth of 3 nm for each emission line
• OD4.5 filtering of unwanted wavelengths (300–1100 nm)
• Designed for color cameras, but equally effective with monochrome cameras
• Special anti-reflective coating eliminates halos
• Near-infrared (NIR) blocking up to 1100 nm
• Can be used with lenses with an aperture of f/4 or slower (use the Highspeed version for apertures slower than f/4)
• Enhanced durability through Ion Gun Assisted Deposition coating on double-sided polished substrate

Ideal applications

• Imaging H-alpha and OIII emission nebulae
• Urban and rural photography
• Creating false-color palettes and enhanced SHO images
• Optimizing Imaging Time with OSC and Monochrome Cameras

Technical specifications

• FWHM: 3nm (+0.6/-0.1nm)
• Maximum transmission: 90% in H-alpha, 82% in OIII
• Out-of-band blocking: ≥OD4.5 between 300nm and 1100nm
• Thickness: 2mm ± 0.05mm
• Unglued single-piece optical substrate
• Surface quality: S/D 60/40 (MIL-O-13830)
• Transmitted wavefront: λ/4 or better
• Parallelism: <30 arcsec
• Mounting: 2” (M48x0.75), ultra-thin to minimize vignetting

Coating technology and reliability

• Ion Gun technology for enhanced spectral stability
• Anti-halation coating to limit internal reflections
• Blackened edges to eliminate stray reflections
• Durable black anodized finish with laser engraving

Use in combination

Combined with the Antlia ALP-T Dualband 3.5nm SII&Hb filter, it simultaneously captures the 4 main channels (Ha, OIII, SII, Hb), offering maximum post-processing flexibility for Hubble palettes and other artistic compositions.

Warnings

• Not recommended for solar imaging
• Not recommended for nighttime visual observation
• Never look directly at the sun with this filter: serious risk of eye damage.