Semi hi-res Eta Carina (Lum only)

[Dennis]

Hello,

Here is a 10 x 180 sec image of Eta Carina, Lum only, as the clouds rolled in (once more!) before I could collect any RGB data. Ironically, when I was imaging M42 the other night, that session was plagued by clouds rolling in from the NE whereas the southern skies were tantalisingly mostly clear.

Last night, I decided to hit up Eta Carina and once I had set up, switched on, aligned, calibrated, etc. it was the reverse – Eta Carina was awash with clouds and Orion was grinning at me from some decent sucker holes. Luckily the capacity to endure such reversals of fortune is in my DNA, being an Englishman!:lol:

Tak Mewlon 180 F12 at prime focus (2160mm) with SBIG ST2000XM. Auto darks applied, no flats.

Cheers

Dennis

[strongmanmike]

Having just recently procerssed a high res version of this same field I am pretty familiar with it Dennis and this is an excellent portrait mate :thumbsup:.

Looks like you have used a filter that has produced a slight mottling in the nebulosity, I am thinking deconvolution or something? When I see this it always makes me kinda question the reality of the details in places...? Do you know what I mean? It is clearly high res but that uniform shapped fine mottling looks to be caused by the processing...? It's just a feeling and I may be wrong :question:...I was wrong once but it was back when I got married (just kidding :P).

Still a great shot regardless :thumbsup:

Mik

[h0ughy]

lots of detail Dennis

[multiweb]

That's a corker Dennis. Very cool! :thumbsup::thumbsup::thumbsup:

[Dennis]

Hi Mike

Thanks for the image review and analysis, it provides some very useful feedback on my processing approach and techniques. I used the convolution filter (Positive Constraint) with default values in CCDStack and this may be the source of the background ripples, unless I have done a COBE!:lol:

I applied a gentle Micro Contrast Enhancement Filter (Topaz Labs) to lift the brighter parts of the image off the page and then had to apply a noise filter in CS5 to tone down some of the background texture in the noisier regions. Some of these filters seem to work reasonably well where there is strong data, but where the image converges to the left of the histogram, there just aren’t enough levels/tones to support these filters.

It was your wonderful hi-res image that compelled to have a go last night – I might just re-visit your image and pinch the colour data!:P

Cheers

Dennis

[Dennis]

Thanks David and Marc – I appreciate you stopping by and leaving your comments.:)

Cheers

Dennis

[strongmanmike]

All sounds very interesting :confuse3::)

When trying to extract fine details in an image I think it is important to make sure you are enhancing or revealing detail that is actually there and not just creating essentially processing artifacts that look like finner details. I see some images that have this look but when you blink them with another high res image it is clear that more detail hasn't really been revealed as such but rather the signal has been changed to look more filiamentous so to speak and maybe the stars a little smaller but no true increase in resolution. The most notorious filter for doing this is the minimum filter, which even with careful use of masks and blending, the levels of detail end up varying across the image so it is hard to tell where the processing artifacts end and the real details start and what is real detail and what isn't. Deconvolution and the shadow highlights filter in PS are easily missused in this regard too the combination of which, to untrained eyes, make an image look like a high res image but in reality it is a case of really only mimicking higher res - if that makes sense :question:.

Not necessarily suggesting the above applies to your image of course, just something to think about :thumbsup:

Mike

[Dennis]

I hear ya big fella. The main technique I use to keep a check on what is real versus what may be processing artefacts, is the use of Photoshop Layers.

I keep the original as the “master” Background Layer and then all my processing takes place on Layers above that “master”. This way, I can easily blink between the master Background Layer and any processed Layers to ensure that no damage is taking place as the data is progressively manipulated.

It also means I can backtrack to any part of the process to return to an acceptable baseline if I have pushed the data too hard.

Cheers

Dennis

[Hagar]

Very nice Dennis. The detail is very good and sharp.
Very nice.