Today, June 5, 2020, I took out the Lunt Engineering 80mm refractor with the Lunt B1200 Calcium K module. I mounted it on the Celestron AVX mount and pointed it toward the sun. Visually I saw the purple glow of the crackled solar surface with three active regions. Two active regions just rotated in view from the eastern limb and the third active region was on the center northern hemisphere of the sun. The southern active region was designated AR12765. I could view three distinguishable sunspots in the active region. Many people ask me why the sun is purple. When viewing the sun with a Calcium K filter, we are viewing a narrow bandpass of light in the 393.4 range of the solar spectrum. this is low on the solar spectrum near the ultra-violet range. It is so low that some people aren’t able to view this range visually. Younger eyes and people who undergo cataract eye surgery are the ones who can usually see the Calcium-K light through The scope.
I enjoy imaging the surface of the sun in Calcium K. It shows great detail on the lower chromosphere which put emphasis on the sunspots, faculae, plage, and super granulation cells.
For the full disk image of the Sun in Calcium K light, I used the ZWO ASI174mm, monochrome camera, on the filtered scope. I centered the Sun on the screen and focused. I use the limb of the Sun to focus and then I digitally zoom in on the sunspot to fine focus. I captured 1,000 frames in SER format and stacked the best 65% in Autostakkert. Once aligned and stacked, I adjusted the wavelets in Registax and processed the image in Photoshop. The last step was to add false color to the monochrome image and orient the sun to its true orientation.