Hbeta & Mg 1 (b2) spectroheliograms 14th Feb 2023

[Alun_H]

A couple of spectroheliograms taken on the 14th Feb with the 72ED,Herschel wedge and Sol'Ex/QHY5III 178M in the lines of Hbeta and Mg 1 (b2),this being the middle line of the Magnesium triplet. Single scans and only processing carried out is rotation to correct orientation,resizing and slight adjustment of brightness levels. Mg 1 scan was affected by drifting clouds.

Alun

Hbeta_14_58_38Z_shift=0_clahe_230214.jpg (82.22 KiB) Viewed 1560 times

Magnesium_15_07_42Z_shift=0_clahe_230214.jpg (88.8 KiB) Viewed 1560 times

[rsfoto]

Hi,

Great results. I am still struggling in getting a reliable result in H-alpha.

Which of the 3 Mg lines from the triplet did you choose ? At the moment I do not understand where the Mg 1 (b2) is. Is it the lowest nm or highest nm value ? Thanks

Rainer

[Alun_H]

Thank you Rainer, the Magnesium Triplet is in the green region of the spectrum between 516.7nm (Mg 1 b4) and 518.3nm (Mg 1 b1)

Capture 2.PNG (70.62 KiB) Viewed 1531 times

The line I chose,the Mg 1 b2 is marked in this picture and lies at 517.2nm

Capture.PNG (86.7 KiB) Viewed 1531 times

Alun

[rsfoto]

Hi,

Thank you very much. I once tried that but I should have chosen only one line and I chose 3 liunes and of course it was a total mess

At the moment it is cloudy.

Rainer

[Alun_H]

Yes,been there and done that myself,ended up with series of black lines covering the image due to ROI being too wide

Alun

[thesmiths]

I've always liked H-beta. The narrow line width means that a lot features are visible, and at the fairly short wavelength, the spatial resolution is very good. It has a lot in common with H-alpha but still looks dramatically different. There are very few commercial filters available in H-beta so the images are quite unique to this technique. It's always nice to compare H-alpha and H-beta taken on the same day.

I think it's nice to compare the non-hydrogen lines to continuum images. You can do this by using a pixel offset to the spectral line in question. You just need to make sure the data off the line is not overexposed.

[highfnum]

h -beta one of my favorites
reason i made my own SHG

Mg b2 is cool also - like a watered down caK

[nicspenceryork]

Brilliant images Alun.
I followed up seeing your post up by watching the YouTube videos about setting up the Sol'Ex. They use finderscopes in those examples. Did you step your 72 down? I have a SW Evostar 80ED DS-Pro and wondered would it be tricky to get that to be compatible with theSol'Ex. Do you know?
Thanks for sharing, really interesting, worthy SPOD!
Nic

[MapleRidge]

Excellent images Alun

I always enjoy seeing these wavelengths that are less common in posts.

Brian

[Alun_H]

Total surprise to see my Hbeta image as SPOD,thank you.

Thank you Nic,Brian for your kind comments. Nic in regards the 80ED,the ideal focal length to obtain full disks in one scan should be between 420-450mm,your scope has a focal length of 600 so will require two scans (top and bottom segments) to build a mosaic,extra work in processing but you will
end up with slight more resolution. As to closing down on the aperture,I find this helps a lot when working in the UV end (CaK line) I will shut the 72 down to 40mm which results in that bit of a sharper focus. For this Hbeta and the other wavelengths I use the scope at its full aperture.

Alun

[DeepSolar64]

Wonderful images! We don’t see enough magnesium and H-Beta here. Isn’t Hb in the blue region of the spectrum?

[Alun_H]

Thank you James,yes Hbeta lies in the pale blue at 4861A .

spectrum.JPG (22.13 KiB) Viewed 1342 times

Alun

[DeepSolar64]

Mix it with the red color of Ha and you get the magenta-pink color of the chromosphere as seen during a total solar eclipse!

[thesmiths]

As to closing down on the aperture, I find this helps a lot when working in the UV end (CaK line) I will shut the 72 down to 40mm which results in that bit of a sharper focus. For this H-beta and the other wavelengths I use the scope at its full aperture.

My main SHG instrument has a 106mm aperture and 720mm focal length. I find that masking it to 72mm aperture (f10) improves the sharpness noticeably for CaK. For H-beta, it seems to work fine at full aperture.

I find the Sun's north and south poles generally do not have so many features, so if you are using a 600mm focal length with a 4.5mm long slit, taking a scan in RA that cuts off the poles does not look that bad (it depends a bit on the time of year -- tilting sun). In fact, I think taking multiple scans and stacking the frames makes a more impressive final image than making a mosaic of single scans (and requires less effort, in my opinion).