Astronomik 1.25″ IR blocking filter

Astronomik 1.25″ IR blocking filter

If you photograph planets or the Moon and want to extract maximum detail from every frame, you already know how damaging infrared light can be to image sharpness. CCD and CMOS sensors are far more sensitive to IR radiation than the human eye, and that sensitivity causes fine planetary structures to blur. The Astronomik 1.25″ IR blocking filter solves this problem effectively: it removes the infrared component of light and passes only the visible spectrum, where your optics perform at their best.

Construction and optical quality

Astronomik is a German manufacturer with a long-standing reputation in the astronomy community, and this IR blocking filter lives up to that standard. The optical element features multi-layer anti-reflection coatings (multi-coating) that minimize unwanted reflections and ensure maximum transmission across the visible band. The filter cell is machined from aluminum - a material valued by astronomers for its low weight, durability, and precise thread tolerances. The filter threads directly into any standard 1.25″ eyepiece holder or camera adapter, making it compatible with the vast majority of telescope setups.

This filter belongs to Astronomik's H-beta CCD series, designed with modern digital sensors in mind. It works excellently not only with dedicated planetary CCD cameras, but also with astro-modified DSLR and mirrorless cameras where the original IR blocking layer has been weakened or fully removed. Paired with a quality apochromat or planetary Newtonian, the filter delivers outstanding results.

Ideal applications

This filter is a universal tool for planetary and lunar photography. The manufacturer recommends it for Jupiter, Saturn, Mars, Venus, Mercury, and Uranus - essentially every visually interesting planet in the solar system. It also proves highly effective for lunar imaging, where it helps preserve fine surface details without the halo effects introduced by the IR component of the light. In addition, the filter is beneficial when working from locations with higher light pollution, since much artificial lighting radiates in the near-infrared band - removing it contributes to cleaner, higher-contrast results.

Recommended for

• Mono CCD cameras used with lucky imaging stacking
• OSC cameras where IR sensitivity affects color accuracy
• Astro-modified DSLR and mirrorless cameras
• Refractors with residual chromatic aberration
• Older lenses that focus IR light at a different point than visible light
• Observers working from light-polluted urban or suburban sites

Why IR blocking matters

Anyone who takes planetary photography seriously will benefit from this filter. Whether you are compositing frames using lucky imaging with a mono CCD, or experimenting with a color sensor, blocking IR radiation helps you achieve a sharper focal point and better overall image quality. The filter is especially valuable when using a refractor with chromatic aberration or any older optic that does not focus infrared light at the same plane as visible light. In such cases, an IR blocking filter becomes almost essential rather than merely optional.

Technical specifications

Summary

The Astronomik IR blocking 1.25″ filter is a compact, well-built, and optically precise accessory that quickly becomes a standard part of any serious imaging setup. Its low weight and standard thread make integration straightforward - screw it in and focus on what matters most: capturing fine details on distant worlds.