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NGC 6995/6992 in HOO with starcolor thist ime

Posted: Tue Aug 09, 2022 9:10 am
by fmeireso
Took many hours to produce something more or less descent.
This is a mono DSLR stack with L-enhance and a plain OSC DSLR stack for the color. Stars look pretty good but i am still unsure about the color of the nebulae itsself.
I could not get it right only when going to HOO it came out better.

Needless to say the starfield is pain in the neck and it really needs much attention in how and what you doing to get it
3,5 hours for the mono stack and 2,5 for the OSC. Scope was an ASKAR FRA 500

acceptable
NGC6995Gimp8 (Medium).jpg
NGC6995Gimp8 (Medium).jpg (371.62 KiB) Viewed 3721 times

Re: NGC 6995/6992 in HOO with starcolor thist ime

Posted: Tue Aug 09, 2022 7:12 pm
by decay
Hi Freddy,

at first: congratulations to your new scope! That's no toy :thumbsup: ! (I revisited your thread on CN.) And I thought, you already had high end equipment ;)

As for your image: the dimensions are quite small. Looking at the filename (Medium) I assume, that you have a higher resolution version ? Maybe it would help to upload it here to get a better view? Is it a crop or most of the FOV?

I agree, the stars (and their colours) look pretty good. :thumbsup: And what did you do in ST to keep the star field under control?

Best regards, Dietmar.

Re: NGC 6995/6992 in HOO with starcolor thist ime

Posted: Tue Aug 09, 2022 9:10 pm
by fmeireso
yes , image is quite small , i had to stay under the 500 kb limit

Better resolution here

https://www.astrobin.com/lq1ohe/

As for controlling the starfield, isolate in the superstucture twice and shrinking module minding the interations...

Still not satisfied about especially the colors in the nebuale....

It was a tough job...

Re: NGC 6995/6992 in HOO with starcolor thist ime

Posted: Thu Aug 11, 2022 3:18 pm
by decay
fmeireso wrote: Tue Aug 09, 2022 9:10 pm yes , image is quite small , i had to stay under the 500 kb limit
To combat this, I usually save/export my images as JPEG with higher compression/lower quality setting before uploading them here. Most times that's not visible at all.
fmeireso wrote: Tue Aug 09, 2022 9:10 pm Better resolution here

https://www.astrobin.com/lq1ohe/
Yes, much better :) :thumbsup:
fmeireso wrote: Tue Aug 09, 2022 9:10 pm As for controlling the starfield, isolate in the superstucture twice and shrinking module minding the interations...
Indeed, isolate two times sounds like a pain. I recently figured out minding the iterations in the shrink module for myself - rather by accident. It does a good job and I think I will try to use it more often in future.

I didn't had such strong problems with the star field in my images of the Eastern and Western Veil. But Stefan (B) reported the same. Maybe it's because my images are not as deep as yours and Stefan's? Maybe a little less (stretching) is better in case of this target?!

Despite this, for me the Veil Nebula is still a very amazing target.

Best regards, Dietmar.

Re: NGC 6995/6992 in HOO with starcolor thist ime

Posted: Thu Aug 11, 2022 7:05 pm
by fmeireso
Yes Dietmar, the veil is an astouding object.

but i found not easy to process.
I think you can use isolate more then once but again caution is to be taken. If you start seeing black spots in you image you have gone too far. Thesame with shrinking. It will not produce black spots but too many stars might dissapear. It is all about balancing.

I come to the conclusion on this objects i hardly use deconvulation...dunno what it is but it seems not much is needed, if any; Maybe it is the scope i have no idea.

Still i am not satified. The background RGB stars are nice, but the nebulae itself, colors are still off imho..what do you think Dietmar? I can't get it right.

Re: NGC 6995/6992 in HOO with starcolor thist ime

Posted: Fri Aug 12, 2022 9:16 am
by alacant
Hi
Lovely shot.
Judging by Google Image, I think any colour scheme is acceptable.
Cheers,
Steve

Re: NGC 6995/6992 in HOO with starcolor thist ime

Posted: Fri Aug 12, 2022 10:03 am
by decay
Freddy,

regarding SVDecon, on most of my images it does a great job. As already mentioned in other topics here, I assume that the image must have enough resolution (slightly oversampled) and that it must be deep enough. I guess, at least the latter is true for your image. Did you leave enough resolution when using the Bin module?

From my understanding, deconvolution can “fix” distortions caused by optics and by atmospheric turbulence. So, if you have a high end optic (you do :) ) and few atmospheric problems, in that case SVDecon probably has nothing to do?! :think:

I revisited my shot of the Eastern Veil. This is what SVDecon does with my image :bow-yellow: .
2022-08-12 11_19_52-Window.jpg
2022-08-12 11_19_52-Window.jpg (156.08 KiB) Viewed 3620 times
2022-08-12 11_23_04-Window.jpg
2022-08-12 11_23_04-Window.jpg (188.49 KiB) Viewed 3620 times
If you like, you could try to compare this with your case.

As for the colours of the nebula itself: I’m no expert, but yes, I would expect something different. But I’m afraid, I don’t have any suggestions for you, as I’m still learning and haven’t combined RGB stacks and bicolour stacks yet. Maybe the other guys here can help, Stefan or Mike for example? They do a lot of this amazing processing ...

Best regards, Dietmar.

P.S.: The fine shot from Steve and my image are narrowband images. But you want to get the "true" colours from your RGB data set. Therefore we cannot compare colours of this different image types, I guess ...

Re: NGC 6995/6992 in HOO with starcolor thist ime

Posted: Fri Aug 12, 2022 6:23 pm
by Mike in Rancho
Yeah Freddy deconvolution should for sure help clarify your stars and the tendrils. Unsure why it doesn't seem to be working for you. :think:

Same with the colors. You can always link the stacks to see what the crowd can make out of it. :D

Have you tried out different combos of Style and RGB emulation?

Re: NGC 6995/6992 in HOO with starcolor thist ime

Posted: Sat Aug 13, 2022 11:52 am
by fmeireso
Here you go Mike

https://www.dropbox.com/s/8qgzoumsbt4f3 ... r.fit?dl=0

https://www.dropbox.com/s/8n85ryvnduji3 ... B.fit?dl=0

First one is the Luminance stack taken with the mono, second the OSC colored one

Both saved as Fits, and aligned

Feel free to play with it...;

Re: NGC 6995/6992 in HOO with starcolor thist ime

Posted: Sat Aug 13, 2022 11:53 am
by fmeireso
Mike in Rancho wrote: Fri Aug 12, 2022 6:23 pm Yeah Freddy deconvolution should for sure help clarify your stars and the tendrils. Unsure why it doesn't seem to be working for you. :think:

Same with the colors. You can always link the stacks to see what the crowd can make out of it. :D

Have you tried out different combos of Style and RGB emulation?
see stacks in post above this one