Ca II K solar activity 30 Dec 2021

[Merlin66]

After fighting the problems of poor USB3 cables all week I managed to find a cable combo which would give me 150 fps with the MiniSHG.

Today's disk shows all the prominent AR's, sunspots and filaments.

Solar disk in Ca II K

111639_shift=0_clahe.jpg (176.71 KiB) Viewed 828 times

The "protus" image shows the large and bright prom.

Solar disk showing Ca II K prom

111639_shift=0_protus.jpg (256.19 KiB) Viewed 828 times

(Using a W47 + Astronomik L1 UV-IR + 1mm exit slit to suppress the background.) , I was pleased to be able to record the prom.

I now have a workable solution for H alpha and Ca II K/H. Just need some practise with the Na/ He/ Mg wavelengths. I do have a collection of green, yellow and other filters.
I'll probably give the MiniSHG a rest for a while and go back to my DIY 1A CaII K filter, Baader Wedge and the DS SM60.......
(BTW Does anyone have the transmission curve for the Lunt Ca filter? UV and/or NIR leakage??)

[DeepSolar64]

Outstanding!!

[Davidm]

Good one! Like the ghostly look of the first shot.

[marktownley]

Outstanding images Ken, really quite impressive what you are able to capture with the mini SHG. Please keep them coming.

Out of band blocking is always essential, in either filters or SHG it seems to give best contrast images.

[ffellah]

Super images, Ken. Very nice to learn more about imaging in the Calcium frequency ! Those proms are impressive.

Franco

[Merlin66]

Thanks guys, appreciate the positive feedback.
I'll use the INTI software to prepare some images in the Ca II K2v and K2r regions as well as the extended Ca II K1.

Close up of K3 and K2 regions

Bray_p88.jpg (80.17 KiB) Viewed 782 times

Composite spectrum across the Ca II showing active and quiet regions

BASS_Project_CaK.JPG (142.83 KiB) Viewed 782 times

[Ylem]

Amazing captures Ken!!

[Merlin66]

With the SHG processing software (INTI) you can apply a wavelength offset (in pixel) and use that data to prepare an image.

With my MiniSHG each pixel (at Ca II wavelengths) is 0.078 A.
The Ca II K3 is on the CWL (central wavelength), pixel offset 0.
The K2 regions are at +/- 0.2A = 3 pixel and the K1 further out.
I selected a pixel offset of 15 (1.2A) to record the K1 band. This would, I think, reflect the performance from the commercial Lunt filters.
The graph shows the position of the various Ca II regions within the Chromosphere.

Phillips_chromo.jpg (88.81 KiB) Viewed 771 times

RESULTS

K3 - T= 6500K, Height=1800 Km Shows the flocculation, bright active areas, filaments and proms

111639_shift=0_K3.jpg (247.16 KiB) Viewed 771 times

K2v - T= 6000K, Height= 1000Km Shows the flocculation as more uniform, active areas, sunspots, filaments and proms - faintly!!

111639_shift=-3_K2v.jpg (253.45 KiB) Viewed 771 times

K1v - T= 4500K, Height= 500Km Shows a more granular surface, active areas, plage and more defined sunspots (umbra/ penumbra) - little !! evidence of proms

111639_shift=-15_K1v.jpg (202.24 KiB) Viewed 771 times

Details of proms (or lack thereof!)

111639_shift=3_K2r_protus.jpg (137.92 KiB) Viewed 771 times

111639_shift=-15_K1v_protus.jpg (146.33 KiB) Viewed 771 times

[marktownley]

Gold standard stuff there Ken, thanks for the additional info.

[Carbon60]

Very impressive, Ken.

Stu.

[Montana]

These are incredible Ken

Alexandra

[EGRAY_OBSERVATORY]

Indeed what more words can describe the incredible and beautifully-coloured captures Ken.

Perhaps the most interesting Calcium images of 2021.

Thanks vm and H.N.Y.
Terry

[Merlin66]

Thanks guys I appreciate the positive feedback!!
(I did look at the possibility of getting images in the Mg II K3 wavelength which lies at the top of the chromosphere (2,000 Km) and 8,000K (approx) See graphic above)
Unfortunately these Mg II lines are only accessible from spacecraft! They sit in the UV at 2796.34A (k) and 2803.52A (h)
https://www.aanda.org/articles/aa/pdf/2 ... 128-15.pdf
Looks like I'm limited to the usual suspects - Ca II K/H, H beta, Fe, Na, He and H alpha.

[DeepSolar64]

Ken,
Nice CaK work. I want badly to get into CaK or CaK observing and imaging. I would use a monitor to do visual. The dang Lunt modules go sky-high when I start planning to get one.

http://daystarfilters.com/Quark/MgIQuark.shtml

Can you image the magnesium line the magnesium Quark sees using your mini SHG?

James

[Merlin66]

James.
Yes , should be an easy target. The Mg I (b2) absorption line is the middle of the Mg triplet, at 5172.8A
I'll image there when I restart the MiniSHG.

[eroel]

Ken:
Super CaK images and information.
Best wishes for this rapidly coming New Year.
Eric.

[Merlin66]

Thanks Eric.
If I only had the seeing conditions you have I'd use the MiniSHG with a long focus refractor to get some CaK close ups. I'm envious of your results!

[DeepSolar64]

James.
Yes , should be an easy target. The Mg I (b2) absorption line is the middle of the Mg triplet, at 5172.8A
I'll image there when I restart the MiniSHG.

Ken,
I look forward to seeing your Mg 1 ( B2 line ) SHG images. Mg is highly underrepresented here. That to me is the greatest thing about an SHG. They can image wavelengths off the beaten path!

HNY

James

[Merlin66]

Jame,
Definitely one of the strengths of the digital SHG.
When you add up all the costs of the various Lunt, Coronado, Daystar filters you would need to cover the more interesting wavelengths it would be a few thousand dollars…….a MiniSHG can be constructed for around $1000, including the camera!
Bang per buck the SHG wins hands down.
Oh, and it never deteriorates over time or needs expensive maintenance or repair.

[marktownley]

What cadence could you record full disk images at Ken?

[Merlin66]

Mark,
I usually scan the solar disk in 9 sec, at 250 fps.

[marktownley]

So it would be possible to capture 5 or 6 a minute then give or take? You could take 10 or so disk images and then stack then in AS3, should iron out some noise...

[Merlin66]

Mark,
Yes, that would be possible.
INTI only takes a few seconds to process an image.
I have stacked four images, worked OK. As the position of the image within the frame depends on the scan start and stop position (and also the positioning of the spectrum within the slit gap) registration can be difficult at times.

[DeepSolar64]

Jame,
Definitely one of the strengths of the digital SHG.
When you add up all the costs of the various Lunt, Coronado, Daystar filters you would need to cover the more interesting wavelengths it would be a few thousand dollars…….a MiniSHG can be constructed for around $1000, including the camera!
Bang per buck the SHG wins hands down.
Oh, and it never deteriorates over time or needs expensive maintenance or repair.

That's a BIG plus! I wonder why no one has produced one commercially for sale?

James

[Merlin66]

Good question!
In a previous life I’d be more than prepared to give it a go. (That’s how the Spectra-L200 was designed and commercialised)
This time round I’ll leave it to others..There’s a manufacturer interested but doesn’t seem to have the drive!
The market isn’t big.
There’s a few trip hazards which need attention to detail.

[MapleRidge]

Hi Ken...

Great shots and I appreciate the additional data you have included too

Brian