Lunt blocking filter for H-alpha sun observation B500 - angled return 1.25″

Lunt B500 blocking filter: Solar observation in H-alpha light

The Lunt B500 blocking filter, integrated into a 1.25" angled return, is an essential component for observing the Sun in H-alpha light. Designed to guarantee total safety and exceptional image quality, this filter is specifically optimized to isolate the Hydrogen Alpha spectral line (656.28 nm). It reveals the fascinating details of the solar chromosphere, such as protuberances, filaments and chromospheric granulation. Compact and reliable, it's ideal for short-focal-length solar telescopes and for amateurs wishing to explore the Sun with a suitable field of view.

What is the purpose of a blocking filter?

A blocking filter is an indispensable part of any H-alpha solar system. Whereas the Fabry-Perot standard isolates a narrow band around the H-alpha line, the blocking filter acts as a "spectral cleaner". It eliminates unwanted harmonics and stray wavelengths, ensuring that only light centered on 656.28 nm reaches the eyepiece or camera.

The B500, with its 5 mm diameter, is specifically designed for short focal lengths (up to 500 mm). It offers :

• A sharp, high-contrast image.
• Maximum safety thanks to multiple filter layers that effectively block harmful UV and IR radiation.

Key features

• Blocking filter diameter : 5 mm (B500), optimized for focal lengths up to 500 mm.
• Integrated angled return : 1.25" format, compatible with a wide range of standard eyepieces.
• Maximum safety : Complies with international standards for safe solar observation.
• Spectral optimization : Eliminates unwanted harmonics to isolate exclusively the H-alpha line (656.28 nm).
• Robust construction: Made of machined aluminum with high-precision optical components.

Why choose the Lunt B500 blocking filter?

• Optimized visual observation : The B500 is designed to offer a field of view suitable for observing the complete solar disk with short-focal-length telescopes.
• Outstanding image quality : Thanks to its multi-layer system, it guarantees sharp, high-contrast images without light interference.
• Absolute safety : Effectively blocks harmful UV and IR radiation, ensuring safe use for your eyes.
• Compact and portable: Ideal for use on the move or with compact telescopes such as the LS40THa or LS50THa.
• Ease of use : Integrated into a standard 1.25" angled adaptor, it is easy to install on your solar telescope.

Recommended applications

• Visual observation of the Sun in H-alpha : Explore solar protuberances, filaments and granulation with optimal contrast.
• Ideal for short focal lengths (up to 500 mm) on compact instruments.