Tzetze

On 12/04/2020 at 18:32, The-MathMog said:

That is one stunning image right there! Great job!

On 13/04/2020 at 09:37, geoflewis said:

Having a slow day today as the weather outside has turned, so catching up on recently posted images and this one is a gem.

23 hours ago, John Nodding said:

Lovely capture! 👍🏻

Noddy

Thank you MathMog, Geof and Noddy. Muchly appreciated.   =]

1 hour ago, ollypenrice said:

On emission nebulae it would certainly be the filter, for me.

Olly

That helps immensely in making the decision, thanks.

2 hours ago, ollypenrice said:

Very good result. Have you considered an Ha layer? It's quite strong in this target.

Olly

Many thanks Olly!

I've been giving some consideration to purchasing an Ha filter. It's on the cards but am torn between Ha filter or more superior grade mirrors as next upgrade. Not sure which option would give me the greater result.

4 hours ago, SyedT said:

I'm not saying it's washed out at all, quite the opposite actually! I think you've blended Luminance very nicely here, which is why I was asking. I'm in a Bortle 5 zone so not too bad, but have streetlamps right next to me which means my exposure times are fairly limited.

It can be so hard to trust my own eyes when processing. Thanks again for kind comments.
There are a couple of issues that I feel let this image down. There's some slight dark ringing introduced at the deconvolution stage which I've found extremely difficult to remove entirely. I also think that the range mask I used should have been smoothed/fuzzed out quite a bit more. The faint stretched outer arm is too pronounced, in my opinioin. A more fuzzy/smoothed out range mask would have softened this area.
I hope to have another go at processing this over the weekend to improve on these areas.

1 hour ago, SyedT said:

Lovely rendition, really liking the colours! Did you not find that 900s exposures in L washed the image out?

Thanks. On other images, I had issues with LRGB combination ending up looking very washed out but, thanks to some tips, have been working on avoiding that with more careful stretching/curves before and after combination. I think I've managed to avoid a washed out look here but perhaps it's something that requires more attention.

26 minutes ago, MarkAR said:

Very nice, colour and saturation look good.

Thank you Mark. I'm pleased with how the colour and saturation turned out.

23 minutes ago, Adreneline said:

Very nice. I really like the level of detail you have revealed in the core region and the fact the outer arm structure is so clear.

Thanks for sharing.

Adrian

Thank you Adrian. The high sub count on the luminance really helped in this regard.

Hi. This data was captured over 4 nights in the last week of March.

Image is comprised of ;

50x Lum, 1x1 900s

15x ea. RGB, 2x2 225s

10" Newt f4.7, EQ8, Atik 460ex with Astrodon LRGB.

Thanks for looking.  =]

2 hours ago, celestron8g8 said:

WOW , great capture and edit !

45 minutes ago, Allinthehead said:

Wonderful image. 

36 minutes ago, Craig a said:

Top draw! 

26 minutes ago, Erling G-P said:

Gorgeous!! 

Best image I've seen of this so far!  Love the colours.

24 minutes ago, JamesF said:

Lovely.  Personally I'd rotate it anti-clockwise 90 degrees, but that's individual choice.  There are so many other little fuzzy blobs in there though.  Every time I look I find another.

James

Thank you all very much for the kind comments. 
James, I struggled over how to frame the target and considered a few options. I tend to prefer a North-mostly-up orientation and try to work something with that aspect. The oblique angles, unorthodox leaning/framing seems to work for me.   =]

1 hour ago, cuivenion said:

Amazing image.

45 minutes ago, Ciaran Meier said:

Wow, awesome  !!!  

38 minutes ago, Brian28 said:

That’s very nice .. ..

Thank you all, muchly appreciated.   =]

1 hour ago, ZiHao said:

Stunning!

Thank you ZiHao. 

With a lucky streak in the weather lately, was able to complete a few datasets. One of which was M106, started back in January.
I've learned quite a bit more about this LRGB processing (particularly, the LRGB combination stage) from some tips kindly provided here following my last processing attempts a few months ago. These pointers have helped immensely in processing this image.

I'm sure this image can be further improved and would be very glad to receive any pointers.

The (Pixinsight) processing steps performed so far, after stacking and performing DBE on the separate LRGB images;

Lum: Deconvolution, Multiscale Linear Transform (mainly detail enhancement with minor noise reduction), Histogram Transformation, HDR Multiscale Transform, Local Histogram Equalisation, (slight) Curves Transformation.
RGB: Channel Combination, Colour Calibration, SCNR, Multiscale Linear Transform (heavy noise reduction), Histogram Transformation.
LRGB Combination, Crop, multiple Curves Transformation iterations.

Image is composed of;
Lum: 22x 900s 1x1
RGB: 15x ea. 225s 2x2
Taken through a 10" Newt on EQ8 mount with Atik 460ex and Astrodon LRGB 1.25" E-series filters.
 

2 hours ago, dannybgoode said:

Lovely image. I’ve made a start on this target but it’s tricky from a light polluted garden. Just need much more data and for that I need a break in the clouds!

Thank you Danny. All the best with your own data!

17 hours ago, MarsG76 said:

Even with the hurdles to jump over, you have a very nice result.. the star bloat might have been caused only by actual seeing.

Thanks very much Mars. I hadn't taken into account the effects of poor seeing.  :facepalm:

So, I've reworked LRGB combination and things have improved somewhat. Certainly a less washed out appearance.

25 minutes ago, wimvb said:

Great image already. Regarding lrgb combination, you have to remember that white doesn't contain any colour information. If you combine white L with colour, the output will be almost white without any colour. Anywhere where you want colour, the L will need to be less than 1 (intensity scale from 0... 1). Adam Block has a good tutorial about lrgb combination in pixinsight. 

https://adamblockstudios.com/articles/Fundamentals_LRGB

Ahh, thank you Wim. This is valuable information. Quality link too, wasn't aware of this resource. You've made something click into place.

I guess there's always something new to learn. I'll make it a priority.  

1 hour ago, x6gas said:

OK, so I will totally defer to Olly on this one (and, in fact, every one!) but....

The Lum layer looks a tad over stretched to me.  I'd be tempted to dial that back just a bit.  Then, if you have PS, I'd be very tempted to switch to that, give the RGB a bit of a Guassian blur, add the Lum layer with blend mode luminance and see what you get.

You're most recent post looks really good but I'm convinced you have excellent data here which has a bit more to give,

1 hour ago, ollypenrice said:

I don't do this in Pixinsight but in Photoshop so I can't help but...

... I agree with this. I often push the L too hard myself then have to go back and re-do it. In Ps I add the L to RGB in partial iterations, reducing colour noise and increasing colour saturation between each one.

I think your rework is a very big step in the right direction.

Olly

Thanks both. I'll try easing back on the lum processing for another run through. PS advice taken on board although I'll admit am reluctant to use more than one processing application. It feels like enough to be trying to get a handle on Pixinsight for now. I'll look further into what's involved with Photoshop.

Hi Olly.

I used the Pixinsight LRGB Combination process, leaving the lightness, saturation and chrominance noise reduction sliders at their default.

I've reworked the image some. On the RGB image, I ran through the colour calibration process again but this really only needed a very fine adjustment. I performed a much heavier noise reduction using Multiscale Linear Transform on 6 layers beginning with a threshold of 8 for 6 iterations and finishing with a threshold of 1 for 1 iteration.

After a light histogram stretch, I ran through the LRGB combination process with a heavier leaning towards both lightness and saturation. Then some further RGB/K, L and Saturation curves adjustments while keeping the background well masked.

I may tweak the curves further, but for now I'm very pleased with what I was able to get out of this with such poor RGB subs. Of course, I'm more than happy to receive any pointers on the areas I've missed. 

Thank you Ian.

I maybe should leave this image as luminance only until I get a decent set of RGB but couldn't resist trying to do something with it. Going to give the colour processing another shot tonight. I did blur the RGB before combination but certainly could have been more careful with the LRGB blending. I'll try a heavier noise reduction and take more care on the combination.

Here's a full res of how the luminance turned out.

Edit: Well, I can see now with a fresh pair of eyes that there is a faint satellite trail still present. There's some considerable noise in the lum here too which would benefit from some further reduction.

I'll have to go back to the integration stage on this..

Happy hangover day, everyone!

I got some decent luminance data on NGC2403 on Christmas eve while the clear forecast held out. Unfortunately, some thin cloud rolled in while gathering RGB subs. Of course, once I'd completed for the night the skies cleared up again. I thought I'd make do with what I'd managed for now and will hopefully acquire fresh RGB subs at a later stage.

The RGB channels turned out very noisy but just about usable. I'm not overly happy with the colour calibration this time around and will have another go at it so am considering this to be a work in progress for now.

Star bloat is quite a problem (0.7776" image scale). I'm thinking I may be able to control this more with the use of masked stretching and elliptical masks. Plenty to improve on here.

Spent a lot of time trying to nail the deconvolution and I think it eventually paid off in this case.

Lum: 23x, 900s, 1x1

RGB: 9x ea, 225s, 2x2

10" Newt at f4.7, EQ8, Atik 460ex, Astrodon LRGB filters.

1 hour ago, dannybgoode said:

Lovely image - a level of quality to aspire to   
 

Quick question - how do you rescale the L shot 1x1 and the RGB shot 2x2. Do you resize the L accordingly or is there another method? 

Thank you, Danny.

I can only speak for Pixinsight processing. Once separate L, R, G and B images have been stacked they need to be registered to each other using the StarAlignment process. A reference image is selected which the other images will be aligned/registered to. If the reference image is 1x1 and the other images are 2x2, the process will automatically upscale the 2x2s to match the reference image.

2 hours ago, tony210 said:

Great image - I find deconvolution difficult and often end up with 20 images which I have to go back to a few days later to choose the one that's both showing more detail and aesthetically the most pleasing(they are certainly not the same thing).- Tony.

Thanks Tony. That sounds much like my own experience with deconvolution. Raccoon eyes and noise are very troublesome to control.

On 18/12/2019 at 14:28, ollypenrice said:

I think the image is very good indeed. Colour and depth are there already. I can't help thinking you could get slightly sharper small-scale detail, though. But this is great.

Olly

Thanks Olly, I appreciate your input. I'm trying to get to grips with deconvolution. It's not proving to be easy, to say the least, but will keep plugging away at it.

On 18/12/2019 at 21:29, Stub Mandrel said:

Very nice 🙂

Thank you Neil.

On 16/12/2019 at 08:35, alan4908 said:

I find the best way to inspect collimation errors is to pick an individual star and then zoom in on it to inspect it in detail. What you should see is all the colours aligning, in your case the red channel is slightly misaligned.  To explain a little further, if I select a star at the right hand edge of the frame I get the image below. The star should be blue but you have a red misalignment effect as shown below in this highly magnified image. Hope this helps !

Alan

Apologies for late reply, very busy time at work for a while.

This does indeed help a lot. I lately did some work on my collimation and thought I had improved things quite a bit but it looks like the misalignment is still present.

Maybe not quite as pronounced as in the M51 image but this is something to work on. I wonder if this is something that can be further improved with collimation. I guess this comes down to optics and OTA quality. I'm curious to see how much improvement can be made through pre-processing though. Roll on Christmas and some free time!

I worked a HDR process into the image, albeit at a very late stage and added to the original post. I would rather add the HDR to just the luminance layer and soften the effect in blending during LRGB combination. Again, a decent starmask would have smoothed out the core better than this result.

Thank you Alan. Those are some great pointers to work on. I skipped the HDR process completely as applying to a range mask, while improving the core, was not improving the whole image. Now that I think of it in hindsight, this was a wide range mask, if I were to use a narrower range mask (with subtracted starmask) I should get better results. However, I do like your tip on applying to preview selection only. I wasn't familiar with that script, sounds very useful indeed.

I hadn't noticed the red misalignment and to be honest I still can't see it but this is either due to a slight red/green blindness on my part or I don't know what I'm looking for.   I'll use your recommended settings in future though. Thanks again, that's very helpful.