An amazing M104

[EzyStyles (Eric)]

very nice M104 there! alot of details for sure. I can understand from where Mike and Steven are coming from. Personally, i do infact think it is slightly over-processed but at the sametime, it clearly shows there are alot of data esp with the inner disc the details are stunning. wavelet in registax have been used abit too much which although sharpens the details, but at the sametime, alot of finer detail will be lost similiar method when using unsharp masking too much in photoshop.

Overall, still an impressive image with alot of detailss.

[Garyh]

I have similar views to Eric to the image. Has been overdone in registax wavelets that has really brought out the noise and artifacts yet a lot of the brighter details are real while the fainter details are a combination of data, noise and processing artifacts..
I would love to see this image processed using a lighter deconvolution without the artifacts and more ideally triple the data collected.
Still it shows what a 14" RC can really do..
I`m jealous
cheers

[Peter Ward]

Image processing can go one of two ways, either you enhance aspects of an image that are already there, or you create information, that has simply has no physical counterpart.

The latter may still have some "artistic" merit but instantly looses all credibility in terms of information about the object.

This begs the question, at what point does passing a mathematical transformation over pixel values go from "enhance" to "alter".

At one end you could simply use Photoshop and airbrush/or remove any feature you like.....akin to the flawless (and false) complexions seen on models in the fashion mags.....at the other you would would highlight every single pore/mole/zit on Jen Hawkins' (still very pretty) face...and hardly the way to sell cosmetics....but from an astronomical imaging point of view far more valid, as that process is simply highlighting something that is real (albeit not as severe) and you are making it easier to see.

Astronomical image processing errors can include dark rings around stars, noise removal (smoothing) that removes data, and our old friend colour balance, ie making something inherently red look blue

Learning how to deal with these issues can be a lot of fun, but for the most part I've found you need good data to start with. As the old saying goes, garbage in, garbage out.

[Bassnut (Fred)]

Peter

mmm, "enhance" to "alter". Very valid point. You could also argue there are 2 other kinds of images, artistic and accurate. Just about all NB pics fall into the former for instance, given colour rendition is abitrary. I find myself sometimes looking at astropics just looking for something different . 3D ness, wow ness, striking colour, whatever, just to seperate it from the norm. The ring artifacts here may well be induced thru processing, but in all honesty, without a comparison, id rather see sharp "dust ring like" detail than accurate blured blotches. I think this M104 gives a better "feel" of how the galaxy looks like generally than a blured accurate rendition. Now, before I get flamed to hell, of course, obviously, Id rather see a razor sharp super accurate Hubble pic, but ive already seen that. Given this was done with something less than Hubble, with short exposure times and a synthetic green channel, I recon it "looks" great. Most over processing just looks wrong and does the image no favours. In this rare case, I think it actually improves its "viewability", without seeming like deliberately cheating.

[Zuts]

Hi Fred,

What you have done is no more than what Peter Ward suggests us DSLR folks do. Up the red during processing which our cameras cannot capture so we dont get blue spiders. To my eyes the image does not look very overprocessed, even if we spend 100,000 bucks on equipment we cant have a hubble; and i think the processing you have done has produced a very striking image and allowed us to see more (rather than less) of what that galaxy looks like.

When it's all said and done I think that it's a bloody good image.

Paul

[Peter Ward]

I never said the image Fred pointed us to wasn't striking (Fred already knows I gave it a big thumbs up ) . But that was not my point.....

I find it laughable for example to suggest, under certain lighting conditions that if a camera renders a models face as green/blue/purple, it be deemed acceptable even though she has pink/fleshy coloured skin.

Image correction is a whole different subject

(Many (daylight) photographers go to some lengths to get the white balance right in their cameras for that very reason....but I digress...)

Getting back to image enhancement, some pretty caustic filters do apply transforms which radically highlight subtle physical processes. There is nothing wrong with that, as this reveals detail that is there, but very hard to see in the original data.

But I'd suggest that is very different to buggering things up to the point where there is stuff in an image, which simply doesn't physically exist.

...but hey, if making the moon look like green cheese makes you happy....go for it......

Originally Posted by Zuts

What you have done is no more than what Peter Ward suggests us DSLR folks do. Up the red during processing which our cameras cannot capture

[Bassnut (Fred)]

Paul, Im with you on that, but a quick reminder, this image is by Richard Murray on my scope, I cant claim credit for his masterfull processing ;-).

[Zuts]

Sorry Fred,

I thought it was one of yours.

Originally Posted by Peter Ward

...but hey, if making the moon look like green cheese makes you happy....go for it......

Hmm,

I dont make it look blue , my camera does. With no post processing it is blue. It has a cutoff above Ha.

Originally Posted by Peter Ward

But I'd suggest that is very different to buggering things up to the point where there is stuff in an image, which simply doesn't physically exist.

By buggering it up do you mean leaving it blue (the tarantula is more brownish, lots of Hb) or do you mean adding the Ha colour that does not physically exist in the data as captured by my camera.

[Bassnut (Fred)]

Look, on second thoughts, Im uncomfortable with "adding" to data that isnt there, thats why ppl send **** loads on gear to start with good data, and its the driving force amongst us all to present truthfull images, other wise you could photoshop master pieces from a $50 Tasco. Im somewhat torn asunder on the way this topic has progressed, I dunno, we often process so much that the real-artistic divide gets blury. As long as the intention is understood, then all is valid I guess. I can be impressed by both approaches.

[Peter Ward]

Paul,

Using an instrument that simply does not record the red bits, does not change the colour of the object. It will however change how the instrument records the object.

Hence my comments on alter vs enhance. If you know the instruments shortfall, then you can compensate for it, and get something that better approximates the original.

To make arbitrary changes (eg green moon) or generate synthetic processing artifacts seems pointless to me

To enhance some aspect of information within the (calibrated) image data....as shown by Richard Murray...takes some skill...and I tend to agree with Fred, can give image a "wow" factor that is often hard to find.

Originally Posted by Zuts

By buggering it up do you mean leaving it blue (the tarantula is more brownish, lots of Hb) or do you mean adding the Ha colour that does not physically exist in the data as captured by my camera.