CaK 17th Feb 2022

[Merlin66]

Seeing was terrible! Swimming!!!!
A selection of close-ups showing the current AR activity.


https://www.swpc.noaa.gov/products/solar-synoptic-map


There's a new small spot appearing in the south east.....


Vixen Custom90,DIY CaK filter and ASI 1600


MiniSHG images to follow - lots of filament and prom activity.

[Merlin66]

Full disk showing the extent of the filaments and a "protus" image showing the many proms.
Enjoy!!!

[John W]

Good CaK images Ken even thou things are relatively quiet at the moment.Cheers, John W.

[Eris]

Quite a comprehensive sharp set of CaK imagery Ken. The last two in particular are showing a wealth of details not evident in a standard CaK setup. Yes, it may be a quiet Sun today but who knows what will come around the corner in a few days time. Thanks for posting.
:thumbsup:

[Averton]

Regardless of the seeing they are great detailed images. Loving the proms at the moment.

[rustigsmed]

nice work ken

[Merlin66]

Thanks everyone for the positive replies, appreciated!
(The MiniSHG image made SPOD on the SolarChat forum)


I've been asked, "Why does the MiniSHG image look so different to the CaK filter image?" Good question.
The bandwidth of the Lunt CaK filter is around 2.4A. This means that most of the light being recorded is coming from the wings (K1 regions) of the CaK absorption line.
These wings are close, only 500 Km above the photospheric level (i.e. white light, sunspots etc.) , whereas the SHG bandwidth of approx 0.2A allows us to observer and record the detail in the core (K3 region) of the CaK line which sits about 2,000 Km above the photosphere.


An analogy: the CaK filter shows the surface of the skin, spots, wrinkles etc. whereas the SHG sees the muscle and tendons below the skin.


Hence the difference in the two images.
HTH