Antlia ALP-T Dualband Filter Kit 2" – Ha&OIII 3 nm + SII&Hb 3.5 nm

Antlia ALP-T Dualband Filter Kit 2" – Ha&OIII 3 nm + SII&Hb 3.5 nm

Description:
This kit includes both Antlia ALP-T Dualband 2" filters: the 3 nm Ha&OIII version and the 3.5 nm SII&Hb version. Designed specifically for OSC (one-shot color) cameras, this pair enables high-contrast narrowband imaging by isolating the four major emission lines: H-alpha, OIII, SII and H-beta.

The Ha&OIII filter passes H-alpha (656.3 nm) and OIII (500.7 nm) lines with ultra-narrow 3 nm bandwidth, maximizing detail in emission nebulae and planetary nebulae while effectively blocking light pollution, moonlight and airglow.

The SII&Hb filter complements the set by passing the SII (672.4 nm) and H-beta (486.1 nm) lines, revealing structures often overlooked with standard OIII filters. The H-beta band adds significant value when separated from OIII during processing. This design enables advanced false-color palettes like H-O-Hb, S-H-O, and H-S-OHb using only two filters.

Both filters feature double-sided polished optical substrates with Ion-Assisted Deposition (IAD) coatings, OD4.5 out-of-band rejection, and anti-halo technology. Their ultra-thin M48 mounts are ideal for large sensors and minimize vignetting.

Together, these filters unlock full-spectrum narrowband imaging with a color camera—without the need for filter wheels or monochrome sensors.

Technical specifications:
– Size: 2" mounted (M48x0.75)
– Included filters:
 • ALP-T Dualband Ha&OIII (3 nm)
 • ALP-T Dualband SII&Hb (3.5 nm)
– Ha&OIII transmission:
 • H-alpha: 656.3 nm – ~90 %
 • OIII: 500.7 nm – ~82 %
– SII&Hb transmission:
 • SII: 672.4 nm – ≥90 %
 • H-beta: 486.1 nm – ~85 %
– Optical density: ≥OD4.5 (300–1100 nm)
– NIR blocked: up to 1100 nm
– Filter thickness: 2 mm ± 0.05 mm
– Substrate: optical glass, non-glued
– Surface quality: 60/40 (MIL-O-13830)
– Transmitted wavefront: λ/4 or better
– Parallelism: <30 arcsec
– Anti-reflective coatings, halo suppression
– Optimized for color cameras
– Filter ring: ultra-thin, black anodized, laser-engraved
– Not recommended: visual use, solar imaging

Additional information:
This dualband combo allows OSC users to capture full narrowband channel sets (Ha, OIII, SII, Hb) and build detailed false-color images such as H-S-O, H-O-Hb or S-H-O. The inclusion of H-beta helps reveal faint structures not visible with OIII alone.
Each filter can also serve as a luminance band for narrowband mono imaging. For optics faster than f/4, Antlia offers high-speed versions with optimized CWL.

Technical Specifications Ha-OIII

Spectrum Curve Ha-OIII:

Technical Specifications dualband SII-Hb:

Spectrum Curve SII-Hb: