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Processing Artifacts versus Reality?


Macavity

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cat_ohnoes.jpg.4e09cddae04424d219b636e513dee1eb.jpg

More Cat (killing) Curiousity? :eek:

As I gloat over my White Light, Solar Continuum and (sort-of) CaK images, I do
start to wonder. How much of this is reality and how much (potential) Artifact? :p

If I process a Solar Continuum image through AS!2 and observe the "sharpened"
output files, I get a characteristic patterning even with their modest processing?

SolarCont.thumb.jpg.b655c4c8aae05ed25d7e7621e2978ce3.jpg

Similarly when I (over!) process the "straight output" via Wavelets for myself! ;)

BUT the "dots" seem too LARGE for Convection Granuals? (~1000km wide!)???
The Sun is 1.39 million km across... My images are (roughly!) 1000 pixels wide!
Convection granules would only be ONE pixel wide across? Maybe they would 
be around / below the resolution of my ED66 'Frac? So what ARE these dots? :)

And should one ENCOURAGE them? :D   (Or What am I missing here?)

P.S. I'm OK with my "CaK" images showing "super-cells" (~35000km wide). :cool:

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You need at least a 100mm aperture and very good seeing to resolve the solar granulation.

I think what you are recording is the macro cell structure similar to the flocculation cells you find in CaK

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6 minutes ago, Merlin66 said:

You need at least a 100mm aperture and very good seeing to resolve the solar granulation.

I think what you are recording is the macro cell structure similar to the flocculation cells you find in CaK

I am pretty sure my 80mm triplet shows granulationSun_123958_lapl4_ap453LRcroppedcolour.thumb.jpg.1308dc4a8e737c13aa031260d2204826.jpg

The grains you see could simply be a mixture of artefacts such as noise and some true structure at a smaller scale being enhanced by deconvolution or unsharp masking if the sigma parameter is set too wide

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I used to wonder about this to start with , but direct comparisons between my results and the 4096px SDO data eased my worries and confirmed that I was capturing fine granulation details ... or at least capturing what SDO was albeit at a slightly lower resolution ... :happy7:

 

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I agree with Michael. Over-sharpening in case of this image is also demonstrated by the "turned edge" - the white ring along the limb. I remember it well from my too-eager WL processing efforts from a few years back ;)

In general, I discourage using the "automatically sharpened" output files. You should consider each image (or image set) separately and fine-tune sharpening parameters, be it wavelets or deconvolution.

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Thanks everyone! I can certainly be persuaded that granules can be seen.
At worst I may be producing some "convolution" of the underlying ones? ;)
I am heavy handed with processing! (Noted the image by Michael above).

I did have another go at processing my Barlowed *ED66* CaK filtered data.
Mostly trying to do something as a bit of change from my WL & Ha stuff! :p

This my independent effort using RS5 Wavelets:

Wavelets.jpg.f9adb2c53111b5de6631e2aa4d7b556a.jpg

Now an offering using ImPPG (I rarely try this):

ImPPG.jpg.e29f4bee41d1688d516e69cb2d2f4b7b.jpg

I even looked up the *colour* of CaK! (393nm):

CaKColour.jpg.6071dfcd24a39cce5471844d03ee4514.jpg

Not too far removed from the colours NASA use for such things!
https://www.nasa.gov/feature/ground-based-schlieren-technique-looks-to-the-sun-and-moon

But a bit "Katie Price" for my taste? Heheh! Interesting as this is,
I am trying NOT to make this a FULL TIME JOB! (Honestly) lol :D

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1 hour ago, Macavity said:

I am trying NOT to make this a FULL TIME JOB! (Honestly) lol

So more cat killings tomorrow then Chris!

 

Seriously though, I think it's definitive that you are indeed capturing something. Now the funny thing is that since I got my wedge I started using IMPPG for deconvolution, it's giving much better results than I can achieve with wavelets in RS, to my eye anyway.

However I've been holding back, thinking that a lot of what I was seeing was Michael's sigma effect, however I'm not so sure now. I'm going to redo a few and compare with SDO just to be sure.

So as always with your musings no cats died - in vain anyway.

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Interesting. So I'd written a lot of this off as artefacts and was using a lot of median filtering & NR. to the detriment of detail in spots.

Turns out I'm capturing reasonable detail.

My image rotated and the SDO image shrunk a little to get them almost matched. Both images scaled to 200% size so we can have a proper look. No other processing on the SDO image.

Some of it is clearly artefacts but some of it is near enough for gubmint work I'd say.

SDO-Comparison.thumb.gif.b31a6073ef10a15f5292fdcbe40d93d6.gif

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Impressive Stuff! I admire your patience re. superimposing your own
and the SDO data! But one feels it must mean something positive? :p

I note near pixel perfect correspondence between my (over-cooked)
Registax 5 & ImPPG results. I will (at least) to move to Registax 6! ;)

I need more *practice* with ImPPG. I remark it *seems* to render
tighter images of my pseudo-CaK *super-cell* edges. These, to my
mind should be like dots - A "String of Perls" at higher resolution...

Aside: Very happy with AS!2 now. Don't need to store loads of .AVI
files (which I never seem) to reprocess --  .TIF files should suffice! :)

Several days of grey skies here now? :o But, having "re-discovered"
my MAK150, I might "clone" the ND5.0 Baader Filter with ND3.8?
Still have the 5" hole saw... Provided I retain all fingers and toes! :evil4:

MAKFilt.JPG.cb65a35a8897acf9602ba3ba6456ab77.JPG

Thanks again to all our readers!

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