08Aug Disk: Spectral sweep through H-alpha.

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08Aug Disk: Spectral sweep through H-alpha.

Post by p_zetner » Wed Aug 15, 2018 4:22 pm

Hello Everyone.

Here is an animation showing the solar disk in a spectral sweep through the H alpha line. The change in wavelength from one frame to the next is 0.054 Angstroms and the wavelength offset (in milliAngstroms) from line centre is displayed in the upper left portion of the frames.

The spectral bandpass of the spectroheliograph in its present configuration is ~200 milliAngstroms (fwhm).

Cheers, Peter.
2018-08-08-083838-Ha spectral sweep.gif
2018-08-08-083838-Ha spectral sweep.gif (6.58 MiB) Viewed 934 times
Last edited by p_zetner on Wed Aug 15, 2018 6:36 pm, edited 1 time in total.

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Re: 08Aug Disk: Spectral sweep through H-alpha.

Post by p_zetner » Wed Aug 15, 2018 6:05 pm

Here is a montage of the 25 frames of the animation showing the actual intensity variation from frame to frame (a few of the frame numbers are displayed). I eliminated this intensity variation in the animation (using histogram normalization in ImageJ) because it made the central frames of the animation too dim to view. As in the animation, the wavelength offset between adjacent disk images is 0.054 Angstroms.
2018-08-08-083838-10xx_flat-div_skew-corr_Montage_01-25_siz_lbls.png
2018-08-08-083838-10xx_flat-div_skew-corr_Montage_01-25_siz_lbls.png (837.46 KiB) Viewed 927 times
The montage I posted here was considerably downsized from the original.
I've uploaded a higher resolution version (half original size) with full labelling here:

Thumbnail: https://www.astrobin.com/full/361701/0/
Full resolution: https://www.astrobin.com/full/361701/0/?real=&mod= (needs time to load.)



If I take the mean disk intensity in each frame and plot it (blue crosses) on a measured spectrum it matches the H alpha line profile pretty closely, as expected but always a pleasant surprise when things work out!
Montage_110946-23frame-avg_083838-10xx-Int-plot.png
Montage_110946-23frame-avg_083838-10xx-Int-plot.png (162.37 KiB) Viewed 927 times
The image to the left is an average over 23 frames of a (spectral) calibration video taken with the spectroheliograph. The yellow box shows the region of the spectrum (approximately) that is plotted on the right side of the figure. The spectrum is calibrated in wavelength using line positions from the BASS2000 solar spectrum.

Cheers, Peter.
Last edited by p_zetner on Thu Aug 16, 2018 4:43 pm, edited 1 time in total.

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Re: 08Aug Disk: Spectral sweep through H-alpha.

Post by marktownley » Wed Aug 15, 2018 7:46 pm

This is excellent Peter and a reference for all as to what is on band and what is not...
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Re: 08Aug Disk: Spectral sweep through H-alpha.

Post by Montana » Thu Aug 16, 2018 9:38 am

This is a really useful set of images, a bookmark I think :hamster:
Thanks for this :bow
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Re: 08Aug Disk: Spectral sweep through H-alpha.

Post by christian viladrich » Thu Aug 16, 2018 10:06 am

Marvellous and very informative. Thanks for sharing !
Could you slow do a little bit the movie ?
It seems to me that the "spicules bushes" are best visible at +/- 0.4A.
Could you make another monatge with larger resolution ? Let's say with the solar disk twice the size of this first montage ?
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Re: 08Aug Disk: Spectral sweep through H-alpha.

Post by p_zetner » Thu Aug 16, 2018 4:29 pm

Hi Christian.
The montage I posted here was considerably downsized from the original.
I've uploaded a higher resolution version (half original size) with full labelling here:

Thumbnail: https://www.astrobin.com/full/361701/0/
Full resolution: https://www.astrobin.com/full/361701/0/?real=&mod= (needs time to load.)

Cheers, Peter.

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Re: 08Aug Disk: Spectral sweep through H-alpha.

Post by Carbon60 » Fri Aug 17, 2018 6:21 am

Excellent work, as always, Peter. Very helpful to see the sweep like this.
It's interesting to see the various subtle Doppler effects within the filaments as the sweep progresses through the wavelengths.

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Re: 08Aug Disk: Spectral sweep through H-alpha.

Post by p_zetner » Thu Aug 30, 2018 10:25 pm

Thanks, Stu.

I find the behaviour of the filaments, as you sweep through the line, interesting as well, especially the one lying halfway between disk centre and the E limb. A part of it seems to persist over a large portion of the sweep, suggesting a high temperature? I'm just finishing some analysis of its spectrum at the moment and will post the results.

Cheers, Peter.

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Re: 08Aug Disk: Spectral sweep through H-alpha.

Post by Wah » Thu Sep 27, 2018 3:39 am

Wow~!!! Really very high resolution images!!!!! :shock: :shock: :shock:

Do you have more information about the equipment? Thanks!

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Re: 08Aug Disk: Spectral sweep through H-alpha.

Post by highfnum » Mon Oct 01, 2018 8:05 pm

you are the master :hamster: :bow :bow

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Re: 08Aug Disk: Spectral sweep through H-alpha.

Post by MapleRidge » Tue Nov 13, 2018 12:04 am

That is an incredible project Peter...the changes from one extreme to the other are great to see and the transition from frame ot frame in the clip is very smooth. Excellent work :bow

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Re: 08Aug Disk: Spectral sweep through H-alpha.

Post by Valery » Thu Nov 22, 2018 9:04 am

Fantastic!
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