280mm Ca II K at full resolution. AR2661 June 7 2017

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Valery
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280mm Ca II K at full resolution. AR2661 June 7 2017

Post by Valery » Fri Jun 16, 2017 11:07 am

Hi folks,

June 7 2017 I have recorded many movies in H-a and even more at Ca II K line.

I have imaged the sun in the Ca II K line through my 280mm telescope equipped with the ARIES 295mm D-ERF -
a two bands energy rejecion filter, SAFIX - ARIES Spherical Aberration corrector, Edmund 10nm at 430nm pre-filter,
two Ca II K 2,2A PST filters stacked as double stack, 4x powermate barlow lens and Basler 1920-155 camera.





Valery.
Last edited by Valery on Thu Aug 09, 2018 5:02 pm, edited 2 times in total.
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.

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Re: 280mm Ca II K at full resolution. AR2661 June 7 2017

Post by Montana » Fri Jun 16, 2017 11:53 am

Valery, I don't understand, this looks very noisy compared to your lovely shot here which I have compared side by side?
AR2661 June 07 2017 UT 05h 47m C11 ARIES 295mm DERF  CaK DS L.png
AR2661 June 07 2017 UT 05h 47m C11 ARIES 295mm DERF CaK DS L.png (1.13 MiB) Viewed 815 times
Alexandra

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Re: 280mm Ca II K at full resolution. AR2661 June 7 2017

Post by Valery » Fri Jun 16, 2017 12:09 pm

Montana wrote:
Fri Jun 16, 2017 11:53 am
Valery, I don't understand, this looks very noisy compared to your lovely shot here which I have compared side by side?

AR2661 June 07 2017 UT 05h 47m C11 ARIES 295mm DERF CaK DS L.png

Alexandra
Alexandra,

This is not a noise. The image you compared to is the image I took at smaller scale and with spherical aberration not corrected.
So, the resolution is less and the image is smeared (veiled) by spherical aberration (no certain focus).

To be sure that this is not a noise, I processed the image in a three different ways, using three more different algorithms of deconvolution - wavelets, Lucy-Richardson, Maximum Entropy. All these black and white "dots" are present on each of the four images exactly at the same positions and of the same shape and relative intensities. This just can't be a noise.

Thanks,

Valery
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.

Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.

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Re: 280mm Ca II K at full resolution. AR2661 June 7 2017

Post by Valery » Fri Jun 16, 2017 1:19 pm

On other test pictures the details changes identically in a time from one movie to the later one.
If the detail disappears, it disappears at all images obtained with three different algorithm of
deconvolution.



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Last edited by Valery on Thu Aug 09, 2018 4:58 pm, edited 1 time in total.
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.

Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.

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Re: 280mm Ca II K at full resolution. AR2661 June 7 2017

Post by marktownley » Fri Jun 16, 2017 6:25 pm

What does the raw unprocessed file look like? My gut feeling here is that it is sharpened at too large a radius. There is a lack of detail around the pores / spots - they are blurred, but the 'dots' across the image as a whole are much smaller scale (and these 'dots' can be seen in the umbra).

I do like your experiments though! :)
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Re: 280mm Ca II K at full resolution. AR2661 June 7 2017

Post by oreoluna » Fri Jun 16, 2017 10:50 pm

Hello Valery,
Thanks for this interesting report.
Jozef
P.S: I'm already excited about the ARIES D-ERF. ;)

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Re: 280mm Ca II K at full resolution. AR2661 June 7 2017

Post by Valery » Sat Jun 17, 2017 3:47 pm

marktownley wrote:
Fri Jun 16, 2017 6:25 pm
What does the raw unprocessed file look like? My gut feeling here is that it is sharpened at too large a radius. There is a lack of detail around the pores / spots - they are blurred, but the 'dots' across the image as a whole are much smaller scale (and these 'dots' can be seen in the umbra).

I do like your experiments though! :)
Thanks, Mark

1. The smaller the curve wide the thinnier the artifacts the deconvolution algorithm can create with too many iterations.

Of course, I tried different curve wide and different numbers of iterations. In wavelets we just increase the contrast at a given spatial frequencies but the picture is THE SAME!

2. I tried different number of stacked frames - from about 2-3% of best subframes to about 30-40%. Basically the results were quite similar, no principal difference. With smaller stacked best subframes the final picture is sharper, but also noisier.

3. Before sharpening I blurred the raw images with Gaussian blur - to decrease the random photon noise and random read-out noise.
This allows more iterations in sharpening before the random noise starts do destroy the picture.

4. You can see that these "dots" are absolutely different at different places of the image. There is no regular pattern, no random white noise. These pictures on the different places of images always repeatedly appears on the images processed with different algorithms.
More so, they are basically the same on two images taken 30 sec apart.

5. "and these 'dots' can be seen in the umbra "

The umbra is not a black hole, the low and middle chromosphere is here above the umbra. The double stacked system dramatically decreased the photosphere contribution to the image and chromosphere details start to dominate. Here is exactly what happens - middle chromosphere dominates.

6. Finally, I saw most of these "dots" on the screen during movies recodring. There were numerous seconds of excellent seeing here and there on the screen and these calmed ares were fullfilled by these tiny details but not as contrasty.

7. See attached images. Left small one is a part of my image, right small is a Dutch Open Telescope image (third large image) which was modified (diffraction and atmosphere blurred, scaled down and then restored by mixtured deconvolution - as in my image).
You can see all these dots here too. And these dots full correspond to real cells and objects at the original DOT image).

Don't you think, Mark, that too many facts vs gut feeling?

Thanks,


Valery.
Attachments
_C11 v DOT.png
_C11 v DOT.png (177.38 KiB) Viewed 746 times
__DOT AR0815-ca-20051022-104737.png
__DOT AR0815-ca-20051022-104737.png (269.8 KiB) Viewed 746 times
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.

Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.

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Re: 280mm Ca II K at full resolution. AR2661 June 7 2017

Post by marktownley » Sun Jun 18, 2017 9:29 am

I agree with you Valery! After posting my comments yesterday I went away imaging, then was looking on DOT myself, then off went out for food, and here we are now a day later before I got a chance to reply.

I think one thing to keep in mind here from everyones perspective is that you are imaging at a scale and resolution that is unheard of in amateur circles, indeed, you are pushing the boundaries at a range of wavelengths. As such it is important we look at what we are seeing in relation to what is achieved by the professionals.

This image from DOT is a closeup in CaH
20030501-quiet-ca.jpg
20030501-quiet-ca.jpg (241.06 KiB) Viewed 731 times
While you don't have the resolution of DOT you are definitely hinting at these structures, and I think this is part of the reason why (at the scale you're imaging) they could be taken as noise, or sharpening edges. It would be interesting if you do get the seeing again if it is worth upping the magnification with a barlow and see if you can tease a bit more detail out? Not sure what the specific details of the setup you are using, but what is the sampling rate like - undersampled?

All good stuff!

Mark
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Re: 280mm Ca II K at full resolution. AR2661 June 7 2017

Post by Valery » Sun Jun 18, 2017 11:28 am

Mark,

My imaging setup is definitely _undersampled_ !!! I need to use at least 4x barlow lens to keep up with increased resolution at Ca K
wave length. Next time I will try to do so.

Regards,

Valery.
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.

Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.

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Re: 280mm Ca II K at full resolution. AR2661 June 7 2017

Post by marktownley » Sun Jun 18, 2017 1:43 pm

Valery wrote:
Sun Jun 18, 2017 11:28 am
Mark,

My imaging setup is definitely _undersampled_ !!! I need to use at least 4x barlow lens to keep up with increased resolution at Ca K
wave length. Next time I will try to do so.

Regards,

Valery.
That would be very interesting to see. If the seeing isn't playing ball you could try a camera with smaller pixels?
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http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!

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Re: 280mm Ca II K at full resolution. AR2661 June 7 2017

Post by eroel » Thu Aug 09, 2018 2:45 pm

Valery:
I think that you are scratching those structures.
SAFIX really does its job, plan to use mine with the TEC Mak and the Aries ERF when the raining season ends.
Best wishes,
Eric.

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Re: 280mm Ca II K at full resolution. AR2661 June 7 2017

Post by Valery » Thu Aug 09, 2018 5:02 pm

My apologies to all. These images indeed were overprocessed. What I didn't understand is why different algorithms behave similarly in the noising results.

Now my images look much less noisy and very much similar to what professionals obtaining with DOT telescope at Canary Islands.


Valery
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.

Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.

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