Lunt Calcium K Module 18mm BF in 2" Straight Through Tube

Lunt Calcium K (Ca-K) Modules – Unlock the Sun’s Hidden Details  

If you're serious about solar observation, you know that Hydrogen-alpha gets a lot of attention—but there's another key wavelength that offers **incredible insights into solar activity: Calcium K (Ca-K) at 393.4 nm.  

Lunt Solar Systems’ Calcium K modules let you dive into this fascinating part of the spectrum, revealing supergranulation cells, sunspot activity, and magnetic field structures just below the Hydrogen-alpha layer. These modules work with most standard refractors and integrate seamlessly with Lunt’s new Modular Telescopes in their nighttime configuration.  

What Can You See in Ca-K?  
The 393.4 nm emission line is produced by ionized calcium in the Sun’s lower chromosphere. This region is cooler than what you see in H-alpha but still packed with dynamic activity. The brightest areas in Ca-K correspond to strong magnetic fields, making it ideal for tracking active regions and sunspot evolution over time.  

However, there’s a catch—Ca-K is on the edge of the visible spectrum, and many people struggle to see the fine details visually due to natural yellowing of the cornea with age. If you’ve had cataract surgery, you may see more detail than most, but for truly stunning results, imaging is the way to go. Cameras capture Ca-K with incredible contrast, making it a powerful tool for astrophotographers and serious solar observers alike.  

Lunt Ca-K Module Features  
✅ Wavelength: 393.4 nm – right on the UV edge of the visible spectrum.  
✅ Internal Narrowband Filters: <2.4 Ångstrom bandpass for high-contrast imaging.  
✅ Primarily an Imaging System: Due to the difficulty of visual observation for many people.  
✅ Compatible with Most Nighttime Refractors – No need to buy a dedicated solar scope.  

Choosing the Right Ca-K Module for Your Telescope  
Lunt offers different blocking filter sizes depending on your **telescope’s aperture and focal length**. Here’s a quick guide:  

- B600: For telescopes up to 100mm aperture and 600mm focal length.  
- B1200: For telescopes up to 100mm aperture and 1200mm focal length.  
- B1800: For telescopes up to 100mm aperture and 1800mm focal length.  

Order your Lunt Ca-K module today and start exploring a new dimension of solar observation! ☀️🔭