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A valid technique or cheating?

samtheeagle

By samtheeagle
in Imaging - Discussion

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samtheeagle

samtheeagle

Posted
Posted

So I managed to get about an hours worth of data of M31 last night, and having stacked in DSS I'm attempting to process to get a nice final image... Having played around a bit with the RGB/K levels in DSS I've got a bunch of differing results.

On the one hand I've manage to pull out some nice detail at the expense of colour:

vzKFf.jpg

Another fiddle gave me the colour back, but with a lot less detail showing up:

mZJ84.jpg

Now I'm sure that if I knew what I was doing I could process this much better with any jiggery pokery, but I don't so I tried a little experiment. I used the pixel math feature of PixInsight LE to add the two together:

ILwOO.jpg

This seems to give me a combination of detail and colour... Albeit with some exaggerated sensor bloom in the top left, but I didn't have a chance to get the darks I needed. :o I'm quite pleased with the result, but is it cheating? Is this a valid approach? And if not how on earth do I get the balance of colour and detail that I'm after?

Technical gumph: I used my f/5 102mm refractor, an unmodified Nikon D70 and a Sky-Watcher LP filter. The images were captured at ISO 800. The stack was 12 images, 11 @ 5 minutes and 1 @ 10 minutes.

Cheers in anticipation of words of wisdom!

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steppenwolf

steppenwolf

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Absolutely NOT cheating. I often use multi-layers, each with different processing of the same data applied, it is all part of the post-processing of the data to produce a fine image. The only 'cheating' really is to incorporate something that was not in the original data and not of your own work but it is quite acceptable to use data from another session and combine it with this session - in fact this too is very common!

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PeterMammoth

PeterMammoth

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How about taking the hue and saturation from the colour image and adding it to the value of the detailed image. I just tried this with your images and it looks okay. See attached. I decomposed each image into HSV components and composed the three relevant ones into the new image.

post-17350-133877401038_thumb.jpg

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samtheeagle

samtheeagle

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Oooooo contentious issue eh? :) Well for my current purpose I arrr mowslty after prettiful things...

Thanks for the comments all, very happy to learn that I'm on the right track. I had a quick play late last night, and to be honest I was a little disappointed with the results. But going at it again with my new approach has really improved the image... Feeling much more positive about my imaging efforts now! :o

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Tim

Tim

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That's coming along nicely there.

As Steve says, the only way to get the best out of your data, is to split it into different layers and treat each one seperately. That way you can bring out the good bits, while minimising and reducing the effects of the atmosphere and seeing etc.

I can assure you that all those awesome image taken by Hubble have been subjected to exactly the same treatment. The colours and other effects applied to the mono images they capture are all a compromise of sorts, but who would doubt their benefit or question their results? At the end of the day, I think most of us want to be looking at a pretty picture :o

cheers

TJ

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michaelmorris

michaelmorris

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For what it's worth I always work on the principle that it's your picture and you can do what you want with it. I think the only hard and fast rule is don't try to pass off someone else's work as your own (plagarism).

Personally, I try to get 'nice' pictures. I'll never add soemthing that wasn't there in the original data. However, I will ocassionally use 'creative' tools to remove processing artefacts. On lunar images the sharpening process can sometimes burn out highlights - the judicious use of the burn tool can tone these down a little. The heal brush can help reduce radial rings around the edge of Jupiter if applying alot of sharpening. Some may class this as cheating, but frankly I don't care! I like the results.

Here's a picture I captured of the elusive Smurf Nebula in Perseus. I would never have been able to bring out this much detail without the marvellous tools available in Photoshop.:D

post-13232-133877402912_thumb.jpg

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michaelmorris

michaelmorris

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Fine work indeed Psychobilly. I'm glad there's someone else out there that takes amateur astronomy seriously. Personally I'm fed up with these boffoons who just lark about, drink wine and eat chocolate cake!

By the way, has anyone managed to capture M121 (aka Caldwell 666) - the Milk Chocolate Galaxy?

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