Processing Opportunity/Challenge

[avandonk]

I think I have finally got my system under control.

This is a large X1.5 native pixel size image of Carina in 3nm NII 7MB

http://d1355990.i49.quadrahosting.com.au/2013_03/CAR_NII_L.jpg


The data is 17x16 minutes (4.5 hours) with the camera at -35C.

Here is a full resolution compressed 16 bit tiff file to play with. It is untouched after correcting for darks and flats and stacking. The resulting fit file was used to produce a B&W tiff with the fit assigned to all three colour channels.

The file is 218MB uncompressed. Here is a zip version 50MB

http://d1355990.i49.quadrahosting.com.au/2013_03/CAR_NII_L_tif.zip


I would be very interested to see what others can get out of this data.

Always remember that the neatest correct entry wins!

I am in the process of collecting SII, HA and OIII and I will put them up as well.


Bert

[multiweb]

Superb vista Bert! Downloading it now. :thumbsup:

Here's the links:

1:1 (http://www.astropic.net/astro/Bert/Bert_ETA.jpg) [6.86MB]
50% (http://www.astropic.net/astro/Bert/Bert_ETA_f.jpg) [4.43MB]

Surprisingly little noise. Nothing to do really but strecth. Top stuff! :thumbsup:

[avandonk]

Marc you have already shown me I am trying to hard to get contrast and then lose real information.

yep ye canna beat many long exposures and dithering with sigma rejection and median etc.

Bert

[multiweb]

We all have different styles of processing. You seem to like the sharper more contrasty type. I'm more mellow. Many ways to skin a cat. All personal preference really. I'm sure others will come with different and more pleasing views.

All I did was:

1_ strecth too versions of the TIFFs. One for the central details and one for the outer nebulae. The trick is not to burn the stars (or as little as possible)
2_ Composite them in two layers in photoshop. Put the sharp darker core on top of the over-stretched one with an opaque mask, then paint the outer area to reveal the faint stuff.
3_ Collapse the two then to a overlay in softlight with a high pass filter at 60% opacity to sharpen a little.

[allan gould]

Agree with Marc. Nothing to do but stretch. So clean data!!!!!
Anyway here is my image which appears to be a blend of both of both your procedures - doesnt need sharpening.
My PSD file is over 2 Gb and the reduction to a 200kb jpeg is rediculous.
Allan

[avandonk]

Stunning version Allan!

I knew this would be a good idea as there is a wealth of knowledge here at IIS that we all should revel in.

My forte is data collection not data processing. I still have a lot to learn.

Keep them coming and we will all learn!

Bert

[Joshua Bunn]

Thanks for the post Bert - and others, Watching and learning.

Josh

[marc4darkskies]

You've got some great data there Bert!:thumbsup:

My quick & dirty version merely shows that there is almost no place in this field devoid of neb so there is very little (if any) "black".

It looks harsher than Marc's but that's done to highlight the detail inherent in areas that would otherwise look a little flat. It depends how you want to present the image - full res or scaled down. Scale can dictate the amount of contrast you need to display for best effect. Scaled down you may want a softer look than what I've done to avoid the overcooked critique. I can tell you though, at full res, my additional contrast yields an image rich in detail.

Cheers, Marcus

[leon]

If only I knew what to do here, some great results indeed.

Leon

[strongmanmike]

Wow man, now that's what I'm talki'in'bout! :eyepop:
Awesome data there Bert, knew that scope was from the Gods :thumbsup: (Italian Gods)

Marc's version is cool

Marcus's version shows just how much is there

Allans..?..well that's..?..I dunno? How'd ya do that Allan? :question:...I'm thinking Pixinsight ala Rogelio Andreo'ish..?

My version is a quick attempt at keeping it kinda real :shrug:

HERE (http://upload.pbase.com/strongmanmike2002/image/149023185/original)

Mike

[marc4darkskies]

Just to try and illustrate what I meant in my post above - here is a much larger (50% scaled) version Bert. Screeds of detail and nuance and lovely to swim around in.

http://upload.pbase.com/gailmarc/image/149024144/original

Cheers, Marcus

[cybereye]

Hi all!

For what it's worth, here's my effort at processing Bert's data. Bert you forgot to record the noise!!

Cheers,
Mario

[multiweb]

It is really interesting to see how the same data turns out with people interpretations. Very different versions. It shows that the objects we take pictures of will always look different no matter what and it all comes down to personal preferences and perception rather than technique.

[strongmanmike]

Quite amazing data huh Marcus? :thumbsup:

Mike

[strongmanmike]

Except at cleaning his house :eek: :rundog:

[marc4darkskies]

Yes, absolutely - wish it was mine! :)

[JohnG]

My 0.2 cents

Bit of Levels and Curves, run through with Power Detail Extract action, bit of readjustment. No sharpening at all.

Lovely data.

Cheers

[allan gould]

No Mike all done with PS3 extended with levels and curves with a little masking. No sharpening or Pixinsight magic. Too Vegas for you?
It's such great data which has been a real eye opener to process.
Allan

[multiweb]

I think you've nailed it John. That's the one I like the most. :thumbsup:

[avandonk]

Managed to get OIII data last night. The Moon interferes even with 3nm OIII, so there is a bit of a gradient in the blue channel.

Exposures are 17x16 minutes for all filters.

Native pixel size tiff. SII to red, NII to green and OIII to blue. 1:1:1, 56MB

http://d1355990.i49.quadrahosting.com.au/2013_03/CAR_SII_NII_OIII_UNSTR.zip


I am really pleased to find out how much I do not know about processing. It gives me an incentive to learn more.

I cannot even imagine what this data can really look like.

Below is just a stretched version.There is a PN? at bottom left. The green 'star'seems to be a PN as well at bottom right.

Bert

[LewisM]

Thanks Bert for this - MAGICAL data - I am an avid convert of yur techniques.

Anyway, my humble attempt at it (medium JPEG). Could have gone for the really nebulous look, but I liked it contrasty

[LewisM]

And my attempt with the colour narrowband overlaid over the base greyscale, and then tweaked around.

I know it can be stretched further, but it starts to blow out too much - will try some alternate layering

[strongmanmike]

To Vegas for moi?? never...apart from needing some Magenta of course :P

I've just never seen the ECN looking so..?..different...? The outer neb is distinct splodges, looks cool but this can't be real and must surely be a processing artefact?

Mike

[LewisM]

Just for those that like the faint clouds... :)


I have never tried Hubble-esque style before - kind of like it ;) Seeing I have a CCD now, got to try me some narrowband, IF the OSC CCD will allow MUCH of it (SXVR-M25c) - probably not much I guess? :shrug:

[von Tom]

Beautiful work Bert. Here's my take on your original image - I hope you don't mind. First is a starless Eta, second is the nebula as it might look unlit and opaque. Both were done using a star mask in StarTools.

Thanks for letting us have a go :)

Cheers,

Tom

[gregbradley]

I like Marc's and Marcus's versions. Allans is impactful but I agree with Mike, it has introduced processing artifacts that aren't real. Still, a vivid presentation.

The image really has a lot of depth. Nice one Bert.

Greg.

[cybereye]

As a relative newcomer to astrophotography I have found this exercise both interesting and informative, so firstly a big thanks to Bert for initiating this exercise!

The first thing that struck me was the wide variety of results that have been achieved which just goes to highlight that there is indeed no correct result in astrophotography, there are only ever personal preferences. We've got images that go from very contrasty which highlight the broader nebulaic (I think I've just made this word up!) structure through to those images which highlight the very faintest of gas. From what I can see, my image sits somewhere in the middle of the spectrum, neither fully in one camp or the other!

Personally, I think my image processing has been influenced by my work processing seismic data - I tend to follow a similar processing sequence and look for similar outcomes from the processes. In the very beginning I tried to emulate what I saw on this forum, trying to match the likes of Marcus, Mike and Greg. But the conditions that I shoot in coupled with my gear were never going to allow this, let alone my experience and technique.

However, over the last few weeks of rainy weather, I've had plenty of time to sit down and work on my processing techniques as the several repros I've posted will attest. So when Bert's noise free data came along I jumped at the opportunity to see what I could do, to see how I fared in the big league. And although there are a few things I think I need to work on, overall I'm happy with how mine compared to others.

So once again thank you Bert for posting the data and the challenge, and thank you to everyone for having a go. This one thread has given me a great benchmark for me to measure my progress through this wonderful passion.

OK, back to processing seismic data before the boss sees me on IIS!!:D

Cheers,
Mario

PS Yes, I am at work at 6:40am - rush job!!!

[irwjager]

Absolutely exquisite data Bert - I can't believe the fidelity and low (non-existent) noise! :eyepop:
My quicky with StarTools (http://startools.org/download/TutorialResults/Bert_Carina.jpg).

[dvj]

Now that IS interesting and different processing. Kind of a low contrast HDR effect here. Is that a script in StarTools?

[irwjager]

It's a combination of Deconvolution (the resolution and stellar SNR of this data is wasted otherwise!), automated scene-based global stretching (manual curves are sooo 90s :P), local histogram optimisation and equalisation, topped off with some inter-scale aware wavelet sharpening of the larger structures. Not more than 5 minutes work.

I'm not a fan of too heavy-handed local dynamic range optimisation (e.g. the infamous 'flat' PixInsight look that destroys large scale detail/depth), so your description of "a low contrast HDR effect" is spot-on! :)

Happy to explain each step/algorithm in detail!

Cheers,

[avandonk]

So if I understand correctly Ivo you are doing for deep sky images what the planetary imagers are doing with their low contrast data?

I have a stack of 3nm NII and HA data of 27x16 minutes ie 7.2 hours. The best 80% of 34 frames. I would be very grateful if you could try this data with your methods.

Here is the compressed fit 41MB

http://d1355990.i49.quadrahosting.com.au/2013_03/CAR_NII+HA_80pc_.zip

I collected the HA last night so it is hot off the press.

Bert

[allan gould]

Bert has kindly hosted a link to a larger version of my attempt.
http://d1355990.i49.quadrahosting.com.au/2013_03/Allan1.jpg
Enjoy the artifacts.
Allan

[marc4darkskies]

Holy cow Ivo! You're a fan of sharpening though!! :) Granted this is probably a quick & dirty demo, but I'd be careful deconvolving this data. The stellar profiles don't need to be reduced IMO. In fact, I'm noticing halos around stars. On top of that you've also done wavelet! Consequently it has a classic overcooked look that zooming in doesn't appear to mitigate.

I'm also noticing that you've rendered almost invisible (and maybe even clipped?) the faint extents of nebulosity that are screaming out to be revealed in this wonderful data.

All of the techniques you mention may be applicable to this image but, and notwithstanding personal taste, they need to be done in a selective and controlled way to maintain some kind of natural look.

Cheers, Marcus

[avandonk]

Shush he may do better with better data!

His method is simply enhancing tiny local contrast in nebulosity (I think). This inevitably leads to loss of very faint nebulosity. His algorithm most probably thinks that the really faint stuff is noise!

See I am an expert already!

Bert

[irwjager]

Nothing special about what the planetary imager guys do Bert! It's all just as applicable to Deep Sky Images.
Your data is such a pleasure to work with Bert!
Here is a version processed in much the same way as the other image (with a better star mask this time).
(http://startools.org/download/TutorialResults/Bert_Carina2.jpg)

[irwjager]

I disagree - this data at this resolution is very, very soft, as is to be expected. Deconvolution in this particular image is able to recover a good bit of real data. As a matter of fact, as a validation of the decision to deconvolve, one can now make out diffraction patterns around the brighter stars.
Surely you're not going to seriously argue that this;
http://startools.org/download/TutorialResults/Bert_CarinaBeforeDecon.jpg

is better than this?

http://startools.org/download/TutorialResults/Bert_CarinaAfterDecon.jpg
Yes, you are absolutely correct. I didn't take the time to create a proper star mask for the de-ringing (I just used a quick auto mask), leaving some stars unprotected (for example Eta Carina is fine, but some other smaller ones didn't make it in my mask :)). I tried to do better (time allowing) in the second data set Bert posted.
I don't think you understand what wavelet sharpening is or how it works?
I stated that I left the smaller scales alone and merely increased the prevalence of the larger structures (which the deconvolution cannot have touched). I fail to see how that automatically means an 'overcooked' image? :rolleyes:

Maybe you don't like the local histogram equalisation or optimisation?
Overcooking, to me, means showing features that aren't there (artefacts) or hiding features that are there through the incorrect use of filters. What do you define as overcooking?
Nope. By choice. But you're free to make a different choice. The automated scene (AutoDev) stretching routine comes up with the best possible curve by homing in on the curve that generates the maximum amount of detail for a specific scale. It guarantees that all detail of a specific size (I chose smallest) is maximally visible within the constraints of a global stretch. It allows you more artistic freedom in choosing what the important feature is in your image.
By the way, I challenge you to clip your data in StarTools (except when explicitly allow or in the Layer module) - you won't be able to do it :)
No. Just, no. There is no 'natural' look in astrophotography and anyone who claims they know what it is is a fraud. Strong words, but I'm passionate about this.
Personally, I think you yourself could stand to gain quite bit with your images by getting 'with the program' so to speak, as I don't believe you are getting the most of your data with the tools available these days. If StarTools isn't your cup of tea, PixInsight is also a fantastic way to get more from your data than is possible with a generic application like Photoshop.

Ah image processing... Rogelio Bernal said it best when he said "There are as many schools of astrophotography as there are astrophotographers". :D

Cheers,

[strongmanmike]

Processing Wars :fight:

Good natured ones of course :innocent:

This might rival that Climate Change thread :lol:

Mike :thumbsup:

[irwjager]

:lol:

As long as it furthers our wonderful hobby... ;)

[strongmanmike]

Of course, t'was a good natured comment from an up and coming comedian :P :question: :confused2:

Besides..ones processing technique has no affect on the planet in this case

Mike

[irwjager]

No need to be modest now; IMHO you yourself manage some pretty 'ground breaking' and 'earth shattering' stuff now and then... ;)

[avandonk]

Well Ivo after having a read about what your software does I think I understand what is going on. I am very impressed.

The difficult part is to come to terms with the 'look' of the image. I am sure it is because I/we am/are not used to seeing the real information that is normally hidden. It is akin to seeing everybody without their clothes in public!

There is a Hubble Palette colour 3nm NB image further back in this thread at post 20. Could I impose on you to give that a shot as well. I would be very interested what you can do to minimise gradients, the curse of the widefield imager.

You are of course welcome to use my data as examples etc.

Bert

[cybereye]

Now there's an image no amount of processing will fix!!! :lol:

[marc4darkskies]

Wow Ivo, it's hard to know where to start.



Not arguing that at all. It's clear that you've selectively reprocessed a portion of Bert's image - you've changed what you originally posted and moved the goal posts. I did not critique this image, I critiqued what you posted originally as a whole. So why make the point that sharpening is a good thing? Of course it is! :shrug:



I see that you've fixed it. But wait! ... See the first 3 star images below - from near the top of the frame. The first is my quick & dirty, the second is your first attempt (the one I critiqued) and the third is your "fixed" version. The one that I critiqued (#2 image below) clearly shows less faint stars and less nebulosity - you have hidden or erased information from Berts data. Your second version (#3 image below) shows more neb but the stars are now a wonky shape. To me it looks like your reprocessing is more than just a star mask(?) #3 still has less stars and less neb than it should (IMO).



Really? :question:



But I didn't say that Ivo. Decon and wavelet do not automatically overcook an image. I meant that you had applied (IMO) too much sharpening to the image, period. Like I said, selective and controlled application of any sharpening technique is important - I do it all the time. Would I sharpen this image if I was processing it? Definitely.



Look at the 3 neb images below. The first again is my quick and dirty (no decon or wavelet). The second (#5) is your first version (and the one I critiqued). You see the halos and you immediately notice the huge amount of additional detail. Is it all real, possibly, but I doubt it. Have you corrupted the tonal balance? Yes, IMO. Eg: The blacks are lighter. In your second version (#6) the stars are still a funny shape and the blacks are now almost gone. You're flattening the dynamic range too much IMO. #6 also looks like the fine structure is less sharpened than #5 so I doubt this is just the application of a different star mask. Unfortunately, in your second version you've exaggerated the large scale structure too much for me.

How would I define overcooking? One or more of the following: Oversharpened, over flattened dynamic range, loss of information, creation of structure that isn't real (even if just tonal in nature).



Nice spruik Ivo, but I'm not critquing your software product - I'm not qualified. I critiquing your processing - that's all. Not something I'll soon repeat I might add.



Ooops, you just lost me.:shrug::mad2:

PS: My apologies Bert - your thread again!

[dvj]

In the end it's all 0's and 1's.

[irwjager]

First point of your critique (which is welcomed as long as it is based on factual information and not opinion disguised as factual information) was that the stellar profiles indicated, in your opinion, the image did not require deconvolution. This opinion is demonstrably false, as I have hopefully demonstrated by the decon before and after.
Are you still maintaining the image as a whole does not stand anything to gain by deconvolution?

Secondly, of all people, you should know that sharpening and deconvolution are not the same things, just as 'cars' and Holden are not the same thing.
Different sharpening algorithms are used in different situations. In this case deconvolution was applied with a 2.7 Gaussian PSF in *all* of the images I posted (no changing goal posts here).

Sharpness and visual acuity are subjective measures. Many different factors govern sharpness and visual acquity, with many of them psychco visual. Deconvolution is an algorithm that helps reversing blurs (gross oversimplification) caused by seeing or the optical train, making sure that the viewer gets information that has optimal retinal focus to begin with.

Then there are algorithms that use psychovisual tricks to enhance visual acuity, by manipulating local contrast (Retinex, local histogram manipulation) or enhancing feature sizes on a global scale (wavelet manipulation).
This is false. Compared to the linear and calibrated version of the data, no data was destroyed and data was still brightened.
More so, your version shows 'fatter' stars than needed (a feature I have noticed in more of your images) and less optimal use of dynamic range with no data using the lower 8% of the available dynamic range.
It's a different data set that Bert posted - process it yourself and you should see the same 'wonky' stars!
My bad... it was the word 'consequently' that lead me to believe you thought one ('overcooking') was a consequence of the other ('using wavelets on top of deconvolved data'). I thought you were trying to state a fact rather than an opinion.

You could have fooled me though when it comes to judicious use of sharpening of some of your own images. It is clear that on smaller scales you indeed use some sort of sharpening, but on larger scales your images are disappointingly lacking detail, especially for the integration times quoted. Your Helix being an extreme example (though i appreciate that was recorded in 2009), but even your recent M8 is indistinguishable from a more amateur setup and much lower integration time which directly has to do with your processing;

If all you are doing is a global stretch with small bits of small scale sharpening, then beyond a point of fidelity, you better data is (both visually and mathematically) just wasted. It is only when you start resolving the dynamic range challenged areas in your image (such as M8's core), the fidelity of your data is being used.

The latter paragraph is fact, not opinion. Happy to show the math behind it.
Then it is really time to get with the program Marcus. It is real.
Here are similar results for a program that is not StarTools (PixInsight);
http://astrofoto.euweb.cz/pixinsight/LocalHistogramEqualization/comparison.html
StarTools' algorithm is sublty different, but uses the same sort of Local Histogram manipulation at its core.
Changed the tonal balance? Yes - ofcourse! As I indicated above, you'd be doing yourself and your data disservice if you didn't!
Yes, you're correct - it's a different data set and I used slightly different settings as a result.
I think you mean I exaggerated small scale structures too much in lieu of larger scale structures. I think you were just trying to say that your taste in aesthetics is more about showing detail in its larger context in lieu of less detail? Your images certainly seem to do this?
Even so, be careful when taking a crop when critiquing scale manipulation is like critiquing a classical concert over a phone line; you need to at least be able to hear (see) the full frequency range over which the work is performed and affected (which in this case slightly larger than your crop :)).
Then we're on the same page it seems.
StarTools is a (consciously) not-for profit loss-making endeavor to enthuse more people for our hobby (and offer people stuck in the Photoshop era a very-low-cost way out). There's no commercial motive, so I don't need to spruik for commercial reasons. :rolleyes:
Now that that is out of the way, re-read it as an explanation for why the processed image looks the way it looks.
Don't state your opinion as fact and we're all good :)
Bert has graciously posted this data for all of us to learn from. I don't want anyone to feel any of their attempts are inferior, wrong or 'unnatural', unless demonstrated through fact, not opinion stated as fact or false authority. Even more so when we're talking about narrow band data that is outside the visual spectrum and that no human eye has ever seen. Any references or claims pertaining to what is or isn't a 'natural' look for such data should be taken with the largest possible grains of salt... :rolleyes:
You don't like the look of my (quick) processing - that's cool. Feel free to tell me this - I feel the same about yours. Let's keep things factual and informative though for those who may not have gotten to grips with narrow band data, dynamic range optimisation, wavelets, deconvolution, etc. :thumbsup:

Cheers,

[irwjager]

You are spot-on. The (somewhat extreme) examples posted are really exactly like that - leaving nothing to the imagination.
It is now up to you & me to use this detail to guide the viewer to whatever we want them to look at. Use it all, use nothing, or use something in between - it's up to you.

There is no wrong or right in doing is. More or less detail - it doesn't matter. What matters is that you have the tools and are comfortable using them to express your artistic vision for an image, whatever that vision may be. Like busy images? Cool. Like just conveying the bigger picture and leaving some mystery? Awesome.
Thanks Bert - my pleasure;

http://startools.org/download/TutorialResults/Bert_Carina3.jpg

I backed off a little on the all the detail recovery magic for a more middle-of-the-road approach.

Cheers,

[DavidTrap]

After reading some of your earlier comments, I don't think you can put your hand on your heart and make the first statement.

As for the second statement, I find that the way you have processed the wavelets produces something that I don't believe actually exists. There is a distinctly rippled appearance to the nebulosity in your images which goes against what I expect a "diffuse gas cloud" to look like.

Narrowband processing is extremely subjective. IMHO there aren't too many facts to apply here - a real blurring of the boundaries between science and art. I don't profess to be an expert, having only one tricolour NB image to my name LINK (http://users.tpg.com.au/dctrap/astrophotos/M8_NBHP_fullsize.jpg). Nonetheless, your processing doesn't do it for me.

DT

[irwjager]

Hmmm... Anything I said in particular?
I can't (and won't) argue with belief, David. Even in the face of overwhelming evidence to the contrary; (http://www.usm.uni-muenchen.de/people/preibisch/carina_project.html) the Carina nebula complex is far from a homogenously distributed cloud of diffuse gas. It is a very, very violent place with very active (feedback induced) star formation, gas displacement and concentration.
Fair enough David.

[multiweb]

In this case the details are real David. Have a look at the HST area scaled down to match what Ivo brought out of Bert's data. The patterns are the same. Not artifacts. Although I too like less pushed processing, but it's only a perception.

[DavidTrap]

Well for starters, you've contradicted yourself in the two statements I quoted regarding what the maker of an image might perceive as a natural look. You've also had a go the people's processing skills, and labelled their images as inferior.



Marc, I disagree - I can't see the same effect in the image you posted. I have seen the rippled effect that I referred to in multiple Ha images that I have processed using wavelet tools in PI. I've never seen that effect in images published by professional observatories. I looked at the link Ivo posted about the carina region, and I can't see it in those images either, especially at anything like the image scale of Bert's fine data.

My attitude with every step of processing has always been to make a change and then ask myself, "Does this look real or ovorprocessed?" Usually I go too far and bring it back. When I see that effect from wavelet tools - I always say "too far!"

Enough from me, back to the original topic.

DT

[avandonk]

I am getting ready to collect more data. Meanwhile all you lot can argue amongst yourselves.

The response to this thread was and is amazing. It has obviously stirred the complacent into activity.

There is only one thing better than good argument. It is finding out you are wrong or ignorant. This is how I learn. As I am often both!

If I find out there is an Irish labarinthine component to this debacle then we are doomed!


Bert

[avandonk]

Ivo I had a go playing with StarTools. I will buy it.

Thanks for your input. If you want more data to play with just ask.

Your version of the data is quite stunning. the gradient is gone.

Bert

[irwjager]

I'm not sure how you can misconstrue that from the two statements... :shrug: They complement each other perfectly; I don't like it when people disparage other people's renditions as unnatural or claim to know what a natural image is, as this is a totally subjective thing to which no one has the answer (as you said so yourself).

At no point have I labelled anyone's images or processing skills inferior (which implies some sort of comparison to something that is 'better'). I hold Marcus' skills in high enough esteem to know that everything he has done to the mentioned images has been by choice. I may disagree with that choice (and he apparently does so with mine), but that does not make his (or my) skills inferior. You cannot argue with taste and that is exactly what we seem to have started doing here for some strange reason.

[LewisM]

I believe - PERSONALLY - tonal contrast to be real. These objects are 3 dimensional, and not expanding equally to each other molecule around them. To process them as a "flat" diffuse nebulosity to me is fake, not the other way around. I am SURE that if you were to see a diffuse nebula up close and personal that there would be VAST tonal and wave front detail.

Again, personally, I like Ivo's example - I don't think it is pushed too far. Perhaps mine was pushed too far in comparison? It all comes down to personal interpretation. If someone dislikes a proposed example, please, post your own rendition of the processed data.

A few of the other presented examples displayed an over-exposed core - the central, defining feature of the EC nebula region. Personally, I bleieve this region needs to be presented LESS exposed because this is the part that readily shows up even in the shortest of exposures (heck, it's visible to the visual observer). To stretch the remaining data to show the fainter nebulosity is in many ways more fake than tonally contrasting the more readily apparent nebulosity.

BUT, to each their own. Seems a LOT of angst about very little, since it is all a subjective interpretation anyway.

[TrevorW]

Not one to shy away from a challenge here is my 2 bobs worth

Great data Bert

[avandonk]

Multiweb's (marc) post inspired me to fire up Registar and produce this animated gif. 700k

http://d1355990.i49.quadrahosting.com.au/2013_03/car_H_I.gif


It is the same area of Ivo's version of my data and Hubbles version.

It makes it far easier to pick out the artefacts in the Hubble image. :lol:


Bert

[strongmanmike]

Ah huh!!?? peer pressure! ;) :P

Looks great :thumbsup:

Mike

[irwjager]

Yeah, I caved. :P

Here is another one (http://i.imgur.com/F63GCad.jpg) from one of the guys on Reddit (http://www.reddit.com/r/astrophotography/comments/19rqku/eta_carina_nebula_complex_ngc_3372_ in_hst/) where I posted Bert's data with his permission. This guy does some awesome work and is a huge PixInsight afficionado (who would've thunk with a handle like 'PixInsightFTW') with a similar taste to mine, so the more conservative minded folks might want to look away...

[coldlegs]

Bert
Lovely data mate. Had to have a go so here's mine.
Found some dark clouds on the left side but can't
bring them out yet and it seems like no one else
can either although some got close. Boy we really need
a 2Mb limit for these photos (adjudicator..hint hint).
Used nebulosity (curves/levels stretching) and photoshop
sharpening etc.

Cheers
Stephen

[marc4darkskies]

Weeell :whistle: Not quite true Stephen :D

See my "quick & dirty" 5 min stretching effort in Photoshop (on page 1 of this thread). No sharpening applied (sorry) - just curves, levels and a touch of shadow/highlight to illustrate the extent of faint neb.

This is a 50% scaled image: http://upload.pbase.com/gailmarc/image/149024144/original

Nice job pulling out the fainter bits though :thumbsup:

[Enrique]

I am with you Bert. The one that learn the most is the real winner!

I will learn more because I am the most ignorant. Keep posting please....

Enrique

[dvj]

Best result so far IMHO. No sharpening needed, good tonal quality to the overall presentation. HA images only need a simple amount of processing, but if you give someone a sharpening or noise reduction tool, they feel they have to use them.

Recall what Ansel Adams said: "There is nothing worse than a sharp image of a fuzzy concept"

And my own *******ized verison of one of his quotes: "Photoshop was created to take care of God's mistakes in establishing tonal relationships"

jg

[avandonk]

I need to realign the OTS after some experiments.

This is a natve pixel size RGB. Only corrected for flats and darks and then stacked. 66MB


http://d1355990.i49.quadrahosting.com.au/2013_03/CAR_RGB.zip


Exposures are 20x4 minutes for each of RGB. I have been using the RBI flush feature of the PL16803 routinely and it definitely reduces 'noise' due to ghost images. Especially when dithering.

I discovered this after imaging the Horse Head in NII, I had two 'comets' in all subsequent frames of Thor's Helmet. These 'comets' just happened to be where Alnitak and Alnilam were. Their diffuse nature was due to the dithering.

Bert

[irwjager]

Some of his other quotes come to mind as well with regards to this thread;

"To photograph truthfully and effectively is to see beneath the surfaces and record the qualities of nature and humanity which live or are latent in all things."

and

"Some photographers take reality... and impose the domination of their own thought and spirit. Others come before reality more tenderly and a photograph to them is an instrument of love and revelation."

and finally;

"Photography, as a powerful medium of expression and communications, offers an infinite variety of perception, interpretation and execution."

:)

[SkyViking]

Your version is my personal favourite too Marcus, great job. :thumbsup:

[cventer]

This is my favourite as well so far. Too much sharpening in some of others IMO.

[rmuhlack]

Time to join the fray. Thanks Bert for making this data available for everyone to experiment with. Certainly is a very helpful learning tool for a newbie like me to have access to quality data. The "robust" discussion has also been informative, giving an insight into the different processing philosophies employed by the various experienced imagers amongst us.

Anyway, here is my feeble attempt at Bert's RBG data. (processed with PixInsight) :)

[A23649]

Amazing data to play with Bert!
Here is my rendition: http://www.astrobin.com/full/35152/?mod=none

[alistairsam]

Interesting thread and kudos to Bert for sharing his work, but is it really surprising to see the quality of the data given the quality/precision of the scope, mount, camera, filters etc?
I'm not undermining the effort required at all, especially to fix tilt, Just a bit surprised.

[avandonk]

What is not surprising is that many others can get more out of my data than I can. These efforts vary from the sublimely subtle to too much enhanced real information. We all know who was close to ideal as judged by his more knowledgable peers.

I knew I was not doing something quite correct by the comments or constructive criticism of some of the 'old pros'.

This exercise was basically a learning experience for me and I hope others.

What I have come to realize is I still have a long way to go. I also now know the general direction I should take.

I did not want to just blindly plod on in the mistaken belief that the best equipment produces the best results without knowledge and practised skills.

The only winning I am interested in is by doing better than I did last week. After all this is a hobby that hones the mind to wonder at the beauty and immensity in both time and space of what we are imaging.

Bert

[cybereye]

Hi everyone!

Here's my attempt at processing Bert's RGB data using StarTools. A 2x2 binned version of Bert's original data can be found here on AstroBin (http://www.astrobin.com/full/35160/?mod=none).

Cheers,
Mario

[LightningNZ]

My attempt at LRGB with the NII as luminance.

Many thanks Bert for this opportunity to try our hand with such amazing data.

Cheers,
Cam

[dvj]

Those are very thoughtful comments Bert! The RH200 is a great little scope, capable of excellent signal gathering ability regardless of the array or filters used. We all view the world through different personal astetics when it comes to art, photography, music, etc. As we have seen, there are no 2 alike when it comes to processing your data.

[avandonk]

I would like to thank everyone formally that participated in this thread. It taught me a lot about my own lack of knowledge by the vast depth and variation of others knowledge about the nuances of processing.

It also made me realize how good the data really is when I get everything correct when collecting it.

In future when I post an image just ask and I will put up a full res unprocessed compressed file for all to play with.

We take images for us and others to see. There is no point putting them in a metaphorical dark drawer.

I was brought up in the old school of science where information was freely shared. The only proviso was attribution to its origin.

Bert