AR12501 CaK 18th February

A close up of this little active region taken in CaK light at 3300mm focal length with the 100mm Tal100R refractor, homebrew CaK filter and PGR Blackfly GigE IMX249 camera.  It is possible to make out the whorl of the filament that surrounds this active region in the plage surrounding the penumbra.  The seeing wasn't supporting full resolution from this setup as I know it is possible to easily resolve penumbral fibrils at 100mm aperture, and while this image hints it doesn't quite fully resolve them.