Lunt B600 Filter in 2" Straight-Through Tube

Lunt B600 Filter in 2” Straight-Through Tube

Calcium K (Ca-K) telescopes and filters are designed to observe the 393.4 nm wavelength, an emission line produced by Calcium located at the edge of the visible spectrum. This layer lies slightly lower and cooler than the one seen in Hydrogen-alpha observations. The Ca-K emission highlights super granulation cells, which appear brightest and most intense in regions with strong magnetic fields, such as sunspots and other active regions. Studying both the Calcium K and Hydrogen-alpha lines offers valuable insights into the structure, depth, and strength of solar active regions. Lunt Solar Systems’ Calcium K modules are compatible with most standard nighttime refractors or with Lunt Modular Telescopes in their nighttime configuration.

The Calcium K module is centered at 393.4 nm, a wavelength slightly outside the visible spectrum toward ultraviolet. While many people can detect the violet hue, visual contrast may be limited due to corneal yellowing. Individuals who have undergone cataract surgery often perceive more detail. For this reason, the Ca-K line is generally studied using cameras, which can capture remarkable details.

These modules feature internal narrowband filters with a <2.4 Angstrom bandpass, making them primarily an imaging system due to the visual limitations for most observers.

Calcium K Module Recommendations by Telescope Size and Focal Length

• B600: Suitable for telescopes up to 100 mm aperture and 600 mm focal length

• B1200: Suitable for telescopes up to 100 mm aperture and 1200 mm focal length

• B1800: Suitable for telescopes up to 100 mm aperture and 1800 mm focal length