The Distinction between Plage Areas and Faculae

[Newbie]

 

[WildWill]

 

Howdy!

Very informative, thank you for that, Newbie! I would only add an historical footnote.
Way back in the day… faculae where known as “Calcium Faculae”.  In the early part of the 20th century, astronomers found that filtering with a very narrow band pass centered on 393nm, the Ca K-line (emission/absorption), would reveal a very detailed view of the faculae, hence the name “Calcium Faculae”.  There is another absorption line for calcium at 396nm, the Ca h-line.  Both provide similar views of the networks of faculae.  Below 400nm, we are moving more into the UV part of the spectrum, so it’s easier for our eyes to see the light, the closer it gets to 400nm. Once you go below about 390, you’ve entered the near-uv part of the spectrum and it becomes very difficult for our eyes to see. Continuing farther into the uv spectrum, one risks permanent eye damage. 
unlike many of the other solar filters out there, the Ca K/H lines are intense enough to be seen using a filter with 5-6nm band pass. 

Here are a couple of images of the sun using a Ca k-line filter. The k-line is a little better for imaging while the h-line is a little better for visual observation. 

 

 

 

pretty cool stuff if ya ask me!

Cheers!

WnA

Edited October 25, 2022 by WildWill

[WildWill]

The bigger picture!