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Can you make my Whale look better? (Lots of data available)


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3 hours ago, gorann said:

Looks great with a lot of fine detail Wim. What settings did you use in HDRMT to get that sharpness? I had a try but there are just so many settings to play with.

Increased sharpness is mainly determined in the deconvolution step. HDRMT only increases local contrast.

Deconvolution 25 iterations, deringing 0.11 I believe, regularisation on two layers.

HDRMT 4 layers to lightness with the  lightness mask option checked. Blend 50% with the non-hdr treated image.

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Tried some deconvolution in PI using Wim's settings @wimvb to sharpen a bit more and added this selectively as lum in PS. Also brought out a bit more dust around the galaxy. Sorry for posting a third version but you got really nice data Nigel that is difficult to stop playing with.

Nigels Whale LRGB PS19sign.jpg

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On 5/2/2018 at 10:01, MrsGnomus said:

I had another go at it this morning from scratch, trying to incorporate Olly's suggestion of pulling out more of the faint structures and also using Wim's idea of deconvolution.  This might be a slight improvement.  I still resorted to PS to get rid of the Lum artefact and for one or two other tweaks, like Unsharp mask.  

B_Whale_FIN.thumb.jpg.a2499b2c7b9c3d58ca9baf1ea47558f6.jpg

Superb job with more outer glow coming into view. I'd still be tempted to brighten and warm up the core reds a tad but this must be close to what the data has to offer (which is a lot - it's great.) My gut feeling is that this is at the limit of saturation and bang up against the noise floor. Really excellent.

Because one of our cameras is very old and has a plethora of dead columns I'm used to clean-up operations, as Mrs G mentioned. I really think that there is very little which can't be invisibly mended! For a background repair in this case I'd just work on the LRGB, ignoring the defect, then do a quick stretch of the RGB to get the background up to exactly the same RGB values as the LRGB (Colour sampler tool in Ps for me) then paste the LRGB onto the RGB and erase the defect.

Regarding the PI and Ps approaches I think another important thing is to pick the one you enjoy using. For me the processing is the fun part of AP and I want to enjoy it. If you enjoy using masks more than layers, or vice versa, base your choice on that.

What a great thread and happy result.

Olly

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1 hour ago, ollypenrice said:

What a great thread and happy result.

Olly

I fully agre Olly!

Most importantly is that Nigel's last versions here showed enormous improvement (although no thanks to me as I could not give any PI advice). Obviously, great data made this exercise particularly fulfilling. Having a 6" refractor of a well known Japanese company in front of the camera cannot hurt.

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1 hour ago, gorann said:

I fully agre Olly!

Most importantly is that Nigel's last versions here showed enormous improvement (although no thanks to me as I could not give any PI advice). Obviously, great data made this exercise particularly fulfilling. Having a 6" refractor of a well known Japanese company in front of the camera cannot hurt.

Exactly so.

Olly

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Inspired by the great images above I gave it another go, this time trying to be a bit more patient and less heavy-handed! I've not tried deconvolution yet but will do. Thanks to @NigeB for uploading.

 

LRGB_02_Final_reduced50_gimp.thumb.jpg.50f9c7655eef25487b6bc1d97d27787d.jpg

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  • 1 year later...

Recently, Göran @gorann and I had a private discussion about this galaxy and faint structures surrounding it, and he reminded me of this thread. Having nothing better to do atm, I decided to reprocess the data, using a few new methods and tricks I picked up in PixInsight.

So here's my latest, and maybe even final, attempt

 

whale_LRGB.thumb.png.5cf66531a71c396feff2c16d5365f64f.png

As before, I created a synthetic luminance from the RGB frames, since the original luminance has calibration artefacts (shifted dust bunnies).

I processed the RGB data for maximum colour punch, and the L data for maximum detail, and trying to preserve the objects in the background. I also managed to pull out a few Ha regions in the galaxy. The data can take a fair amount of deconvolution, as well as stretching. I hope I didin't overcook it too much.

Also, note the very faint smudge at the bottom of the image, towards the left. This is a small galaxy that goes by the name SDSS J124324.90+322854.2, poor thing. It is about at the same distance as ngc 4631 (some 40 Mly according to SED), but I haven't been able to find any data relating them to each other. There is however, supposed to be a faint tidal stream going between ngc 4636 (the Whale) and ngc 4656 (the Hockey stick). Unfortunately, this image doesn't show that level of detail.

https://www.researchgate.net/figure/Final-ROSA-L-image-of-the-NGC-4631-environs-The-image-is-approximately-81-81-in-sky_fig2_267338882

Edit:

This composite image shows the size of the tidal structure surrounding ngc 4631. There is a lot going on in the background, but the data doesn't show any sign of the extension between ngc 4631 and ngc 4656

whale_tail.thumb.jpg.23acce8a1c50a994fd6dc768744512db.jpg

Edited by wimvb
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  • 3 months later...

Hi Wim,

That's brilliant! Thanks for updating and posting your new method. Also interesting point about the tidal stream. Having read this I'm going to have another go at this object, with a much deeper set of images to see if I can bring that out. Light pollution here, while not horrendous, may still limit that, but I'll have a go and post here when I've got something. You can have the data set with pleasure!

Nigel

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