M 82 final reprocess due to bad weather again

[GordonH]

Hi All

You must be getting fed up with my reprocesses but I have to keep myself sane when the weather is bad. Following tips and comments from various people from different forums, I decided to go back to the drawing board on the processing of my M 82 image, this time I did the following

Combined using Sigma Clip with a Sigma factor of 3.0 in Maxim DL

Stretched each master frame using log, maximum pixel value and 16 bit

Saved to 16 bit tiff

Blended 100% Ha to Red channel using normal stretch mode

Blended 20% Ha to Blue channel using normal stretch mode

Nothing done to Green channel

Manually combined RGB channels in Photoshop CS2 using default settings

Levels and curves

Contrast enhancement

Unsharp mask

Shadow highlight adjustments to bring down the core a bit

Mild gradient removal with Gradient Xterminator

Mild noise reduction using Noel's tools

The result is that the background is less black so the comment about clipping the black point seems to be resolved. There is more detail in the red jets than the previous reprocess. I think I have gone as far as I can with the data that I have, unless .........

I think I will try this again when seeing conditions are better as I had to deal with the moon, neighbours lights and a hazy sky, also longer Ha subframes will be beneficial

I have enclosed the final reprocess as well as the previous one for comparison, the first "cigar.jpg" is the final reprocess as described above, the earlier ones can be found on my website Imaging The Heavens - Home Page to see how this image has progressed. Ain't learning fun!!!

Thanks for your patience

Best wishes

Gordon

[Beyond_Vision]

The jets on M82 now stand out more and it looks much better now, but there is now a red gradient at the top and bottom on my monitor.

Regards

Kevin

[barkis]

No 2 is the reworked one. It looks better to me because I saw a green gradient in number one, which crossed the centre of the Image, and the jets in the reprocessed one are a bit more subdued.

Thats how I see it on my monitor. The overall image of the tweaked one, is a lot cleaner to me. Of course I'm not the best image analyst

you will find.

Ron.

[Beyond_Vision]

Ron it's the first pic that is the latest one.

Regards

Kevin

[Psychobilly]

I agree with Ron...

I got a few gradients showing in the "first" of the two pictures as well...

still a very nice pic though ...

Peter...

[GordonH]

Hi Guys

Thanks for the comments, regarding the gradients, I have tried playing around with different settings such as brightness, contrast, etc on my monitor and I can't reproduce the gradients you are speaking of, I even printed out a copy of the image with increased brightness and again no gradient evident. I have noticed this when looking at my images on a different monitor at work and sometimes there appears to be a gradient that wasn't evident on mine. Whether this is a monitor issue or not I don't know but I have had similar comments in the past where some people have said there is a gradient and others including Noel Carboni say there is none

Buy the way the final reprocess is the first one as kevin said

Best wishes

Gordon

[Psychobilly]

I downloaded the 2 pics and had a look at the individual channels...

on the reprocess Theres a "subtle" redder outer ring around a slightly blue green inner circle round the galaxy...

Peter...

[rich_t]

Hi Gordon,

I can just see the faint outer red area on my moniter, I get this on my pics when the sky conditions are not as good as you'd like. I think it was due to the central region been darker because of the SCT secondary obstruction, causing the outer area to be a tad brighter. I took some flats and this seemed to improve it.

Very nice picture!

Thanks,

Rich.