Lunt blocking filter for sun observation in Calcium-K B1800 - 2″ straight tube

Lunt B1800 2” Straight Tube Blocking Filter - Specifications and Features

Visit Lunt B1800 blocking filter, integrated into a 2” format straight tube, is specially designed for solar observation and imaging in the Calcium-K (Ca-K) line, centered on the 393.4 nm wavelength. With a narrow bandwidth (<2.4 Å), this filter reveals the subtle details of the photosphere and solar supergranulation. Thanks to its generous 18 mm diameter, it is optimized for telescopes with focal lengths up to 1800 mm, offering outstanding performance for demanding solar astronomers.

Why observe in Calcium-K?

The Calcium-K line highlights the intense magnetic zones of the solar photosphere and chromosphere. These wavelengths enable us to observe phenomena such as :

• Facular beaches : Bright regions associated with magnetic fields.
• Solar granulation: Bubbles of hot plasma visible on the Sun's surface.
• Sunspots: Dark areas surrounded by shadows.

Although this line is difficult for the human eye to perceive (due to natural aging or yellowing of the cornea), it is perfectly detectable by modern cameras, making it ideal for advanced astrophotography.

Key features

• Blocking filter diameter : 18 mm (B1800), optimized for focal lengths up to 1800 mm.
• Straight tube : Straight 2" design, ideal for configurations requiring a short optical path.
• Multiple connections :
  • 2" inlet for eyepiece holder.
  • 1.25" outlet with integrated T2 thread for camera or eyepiece.
• Narrow bandwidth : <2.4 Å, centered on the Calcium-K line (393.4 nm).
• Maximum safety : Integrated UV/IR protection for safe viewing.
• Robust construction: Machined aluminum case with high-precision optical components.

Why choose the Lunt B1800 blocking filter in straight tube?

1. Advanced visual observation and imaging : The B1800 offers a wider field of view and is ideally suited to modern large-format sensors.
2. Outstanding image quality : Thanks to its narrow bandwidth, it guarantees sharp, high-contrast images without light interference.
3. Total safety : Effectively blocks harmful UV and IR radiation, ensuring safe use for your eyes and equipment.
4. Universal compatibility : Works with all compatible solar telescopes equipped with a 2" eyepiece holder.
5. Versatile design : Ideal for solar imaging thanks to its integrated T2 thread.

Recommended applications

• Limited visual observation in Calcium-K : For those able to perceive this wavelength (especially after cataract surgery).
• Advanced solar astrophotography : Compatible with modern cameras equipped with medium and large sensors.
• Ideal for focal lengths up to 1800 mm: On intermediate or advanced instruments.

Included in the package

• Lunt B1800 blocking filter integrated into a 2” straight tube.
• Adapter for 1.25" eyepieces.
• Detailed user manual.

Compatibility

The B1800 blocking filter is designed for use with :

• Lunt solar telescopes or any system compatible with Calcium-K.
• Standard 1.25" or 2" eyepieces.
• Modern astrophotographic cameras with T2 threads.

Important

The B1800 blocking filter must be used exclusively with a telescope or system equipped with a Lunt Solar Systems Calcium-K module. It cannot be used alone or as an independent accessory on an instrument not dedicated to solar observation.

Transform your solar viewing experience with the Lunt B1800 blocking filter in a 2” straight tube. Discover the magnetic dynamics of the Sun in a unique light and capture its fascinating structures with precision!