Imaging the Sun in CaK!
Sun, like all stars, emits electromagnetic radiation in different colours of light. By filtering out specific wavelengths, one can reveal different portions of the sun’s surface.
Besides basic white-light imaging, most commonly used wavelength for solar imaging is H-alpha. This wavelength is often the go-to for astrophotographers as it offers spectacular views of solar flares and protuberances. On the other hand, dedicated Solar H-alpha telescopes can cost a lot of money and cannot be used for anything else than observing the sun for obvious reasons.
But what if I told you there is a filter that can be attached to any refractor telescope, that could filter out a lot of atmospheric turbulence, and also reveal a whole another world from the surface of our nearest star? Meet the wonderful world of Calcium K-line imaging!
What exactly is the Calcium K-line? This specific 393.3nm wavelength of light is abundant in the surface of the Sun, emitting a bright image to even older monochrome CMOS cameras. Furthermore, when the aperture of the telescope is brought down to f/30 or so the contrast of solar features in enhanced drastically. To do this the simplest way is to use the Antlia Calcium K-line filter with it’s own Herschel wedge that has a built in aperture to adjust the f-stop easily. Bear in mind however that Calcium K-line is not safe to observe visually with any telescopes due to high amounts of ultraviolet light that passes through the filter. Any camera sensor however is safe to use with this wavelength of light.
To find out more check out our YouTube video below!