H-ALPHA ENHANCED UV/IR BLOCKING FILTER

IDAS HEUIB-II

Ideal for astro-modified cameras and color CMOS sensors. Eliminates red color cast while dramatically enhancing red Hα nebulae.
The global standard UV/IR blocking & color-balancing filter for full-spectrum and astro-modified cameras.

IDAS HEUIB-II Filter
*IDAS HEUIB-II (Standard M48 mount) filter appearance. Delivers maximum transmittance at H-alpha (656.3nm) while sharply blocking unwanted near-infrared light.

Eliminates Red Color Cast in Astro-Modified Cameras While Boosting Deep-Red Hα Nebulae

When shooting with an astro-modified DSLR or mirrorless camera (IR-cut removed or full-spectrum modified), excessive near-infrared light and 600–650nm orange-red energy overwhelm the red channel, producing a heavy reddish-brown cast across the entire frame. Conversely, standard off-the-shelf UV/IR-cut filters begin cutting off around 650nm, dimming the vital Hα emission nebulae you modified the camera to capture.

The IDAS HEUIB-II (H-alpha Enhanced UV/IR Blocking Filter II) resolves this dilemma completely. It passes the crucial Hα emission line (656.3nm) at over 90% transmittance before executing a near-vertical cutoff of near-infrared wavelengths above 680nm. Combined with a tailored suppression curve across 600–650nm, HEUIB-II delivers neutral dark skies, blazing red Hα nebulae, and natural foreground colors.

Natural White Balance for Nightscapes & Daytime Photography

By balancing continuous visible transmission from blue (400nm) to red (660nm), wide-field nightscapes that combine the Milky Way with earthly landscapes preserve natural mountain, snow, and foliage tones without unnatural red shifts.

💡 HEUIB-II Spectral Highlights: Maintains >90% transmittance at Hα (656.3nm) while sharply blocking UV below 400nm and NIR from 680nm to 1100nm — eliminating red star bloat (chromatic aberration fringing) in refractors and camera lenses.

Optical Mechanism & Spectral Transmission Characteristics

* High Hα (656.3nm) Transmittance & Red-Cast / Red-Halo Suppression

The root cause of severe red cast in astro-modified cameras is the excess of 600–650nm orange-red continuum energy flooding the red pixels, compounded by near-infrared leakage above 680nm. HEUIB-II gently moderates the 600–650nm region to equalize RGB energy, rises back to over 90% peak transmittance right at Hα (656.3nm), and then steeply blocks NIR above 680nm — preventing out-of-focus infrared star bloat in refractive optics.

* IDAS HEUIB-II Official Spectral Transmittance Data

IDAS HEUIB-II Spectrum Chart

* Official IDAS HEUIB-II spectral transmittance curve. Combines a tailored 600–650nm RGB-balancing curve with >90% Hα (656.3nm) transmission and a steep 680nm+ IR cut.

HEUIB-II Filter 3 Key Strengths

1 Passes Hα (656.3nm) at over 90% transmittance while sharply blocking NIR above 680nm to prevent red star bloat in lenses and refractors.
2 Proprietary RGB-balancing curve eliminates the heavy reddish-brown color cast typical of astro-modified cameras.
3 Preserves natural foreground colors and white balance in wide-field Milky Way nightscapes and time-lapse photography.
💡 Recommended Cameras & Ideal Applications for HEUIB-II
1. Astro-Modified DSLRs & Mirrorless Cameras (HKIR / Full-Spectrum Modified) An essential base filter for any astro-modified camera. Retains 100% of the unlocked Hα sensitivity while cutting the destructive infrared wavelengths that cause red color cast and star bloat.
2. Wide-Field Nightscapes & Starry Time-Lapse (Sky + Foreground) Suppresses unnatural red color shifts on terrestrial landscapes, keeping mountains, snow, and trees natural. Captures red Milky Way nebulae and natural foreground scenery in a single exposure without complex masking.
3. Cooled Color CMOS Cameras under Dark Skies Ideal as an Hα-enhancing UV/IR-cut filter for AR-window cooled color CMOS cameras under dark skies, preventing near-infrared star bloat while enhancing Hα nebula contrast against the RGB starfield.

Specifications & Optical Characteristics

Filter Type Hα Enhanced UV/IR Blocking & Color-Balancing Filter
Primary Passbands 400–670nm Visible Spectrum & Hα Emission Line (656.3nm: >90% Transmittance)
Primary Blocked Bands UV (Below 400nm) & Near-Infrared (680–1100nm Steep Cutoff)
Substrate & Coating 2.0mm Optically Polished Glass + Durable Ion-Assisted Deposition (IAD) Multi-Layer Coating
Available Mount Sizes M48 (48ST2), M42 (OL7.5), M54 (OL7.5), DZ (for ZWO Drawer), DRT (for Canon EF-EOS R), CA (for EOS APS-C)
Manufacturing & QA Made in Japan (ICAS Enterprises Co., Ltd. Optics Division), Individual Spectral Test Report Included

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🌐 Worldwide Availability: For optimal regional pricing and fast local shipping, order via our Authorized Dealers (USA / Europe / Asia) ↗. Overseas orders are also accepted via our authorized shop on BASE (international shipping & handling apply).

💡 Purchase Information & Authorized Dealers

IDAS products are available through our authorized domestic online shop (BASE), as well as authorized astronomical telescope specialty dealers worldwide. For physical demonstrations, mounting consultations, or store points, please visit your local authorized dealer.

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