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Sun in whitelight 9th January 2013 , 10:30 GMT

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#1 steveward53

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Posted 09 January 2013 - 08:30 AM

Back at it again after what seems like an eternity . . .

45 frames stacked in poor seeing.

Couldn't get rid of a strange effect on the edge , looks like a stacking problem but the features all line up OK ?

Posted Image

1000D + ST120 + ND3.8 + 1.8 x Barlow + UHC + S/L.
1/1250s @ ISO 100 , 45/45 , Reg 5.1 , Gimp2.8.

Day by day album . . . http://www.astrobin....rs/steveward53/

#2 Andrev

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Posted 09 January 2013 - 03:01 PM

Wow, these new spots are quite amazing. Very beautiful image.

Andre

#3 BYoesle

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Posted 09 January 2013 - 03:42 PM

Very nice image Steve!

You might be seeing more of a sharpening effect on the edge such as "ringing." I often see this with unsharp masking. Sometimes adding some "clipping" or adding a little gaussian blurring will help.

#4 steveward53

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Posted 09 January 2013 - 05:33 PM

Cheers Bob ,

I had a funny thin halo on the subs that I'm sure was an atmospheric thing , the seeing was poor and the disc appeared to be 'flexing' and had a very rough edge.

Crop from single sub.


Posted Image

Having had a play I can reduce it somewhat by moving the blackpoint on the subs so I will probably just select the very best subs tomorrow , adjust and restack to see if I can improve this one .

going to be cloudy again so need something to do . . . ;)

Steve.

#5 raylal

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Posted 10 January 2013 - 07:50 PM

I find that full disk shot is phenominal, so nice to see so much activity on the surface. Great job Steve.

Ray

#6 tomnjulie

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Posted 14 January 2013 - 01:50 AM

What program did you use to stack these?

#7 steveward53

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Posted 14 January 2013 - 05:35 AM

Reg 5.1 . . . :rolling:

#8 BYoesle

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Posted 15 January 2013 - 03:50 PM

Hi Steve,

I was thinking about this and went back to review the processing of one of my better white light images taken last April. The seeing was excellent (at least for me), so I don’t think that’s the origin - at least of the bright ring aspect of the effect. I too use RegiStax – version 6.

Here’s my original (reduced size) full disc mosaic, showing the “edge effect:” I appear to use a little less contrast enhancement and final sharpening than your image:

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#9 BYoesle

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Posted 15 January 2013 - 03:51 PM

Here’s a raw single frame:

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#10 BYoesle

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Posted 15 January 2013 - 03:51 PM

Here’s an align and stack of the 30 best frames:

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#11 BYoesle

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Posted 15 January 2013 - 03:52 PM

Here’s the wavelet sharpened image, which shows the origin the bright ring of the “edge effect:”

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#12 BYoesle

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Posted 15 January 2013 - 04:11 PM

So a full disk (reduced to fit the posting requirements) with additional sharpening and some brightness and contrast adjustment. Thus it seems it’s the wavelet sharpening generating the bright ring of the edge effect. I do show a bit of ege darkening as well, but the more visible band of inner darkening of your image may be (at least partly) due to poorer seeing:

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#13 steveward53

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Posted 15 January 2013 - 06:41 PM

Hi Bob ,
The effect was showing on my stacks pre-wavelet , and gone today . . . I can only put it down to the seeing . . !

Steve.






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