Clouds..clouds..clouds, so, resorted to re-processing old test data!

[Xiga]

WARNING!!! The following post contains an entirely under-whelming image! 

With nothing but clouds here for what has seemed like forever, and no sign of any new data in sight, i decided to turn my attention to some test data i shot back in August of last year. The reason for choosing this, is that i wanted to see how far my processing skills had come along, and i knew this one would be a serious challenge, as i had basically everything working against me. 

I shot this near the end of August while testing out the new imaging laptop and rowan belt mod for the HEQ5 Pro (which i had installed the previous winter, but hadn't had a chance to properly test). At the time, we were living very near the City Centre, and only had a tiny back yard, so the only target available was the Pac-Man nebula. This is also before i had the D5300 modified for better Ha response. I did however use my IDAS-D1 filter, which enabled me to shoot 8 min subs. So here's a full rundown:

9 x 8 min subs (only 72 mins in Total)

ISO 200

50 Bias and 30 Flats

Stock Nikon D5300 with an IDAS-D1 filter

Skies were SQM 18.7 (Bortle 6)

 

AstroPixel Processor was used to stack (with x2 Drizzle), do an initial stretch, and then perform gradient reduction. Everything else was done in Photoshop. 

I've shown my previous (hideous!) attempt below as well, which was stacked in DSS and also processed in Photoshop. I should say, i don't think APP played too much of a factor in the improvements, it was mostly just down to better Photoshop skills. 

I know i didn't really need to drizzle, i just wanted the nebula to look a bit bigger, so went with the drizzle and then just trimmed the fat off the edges.

Overall i was pleasantly surprised what came out at the end, given this was not much data, done with an unmodified camera in heavy LP. 

Anyways, just thought i'd share, to kill the boredom! 

 

[wimvb]

Looks very good, especially with an unmodded camera. Nothing under-whelming about it.

[MarsG76]

Those pics look great.. Nothing underwhelming about them... I don't know how seeing all those clouds make you feel, but personally, clouds are making me go nuts and full of rage... I wish global warming was real so that the planet would dry up and there would be no clouds ever again... The only ones whining would be hippies and greenies, but who cares what what those wierdos think.

Last night was the pinnacle, looking forward to the lunar eclipse and the one night nothing but thick clouds... The only thing I was looking forward to, working with and pretend being nice to people I literally can't stand, hate really... Thinking this is my night after tolerating the trash, even had that day and next off... But no.... Now I know how the zodiac kinds are made... 

Rant over.

[gorann]

Not bad at all I think Wim, not even the first one looks particularly bad. So you have started using PS! Must be the layer thing that finally dragged you in. There should be some kind of solidarity data base for clear-sky-deprived astrophotographers, where those living in dryer areas can upload surplus data to keep us from going insane....

[wimvb]

1 hour ago, gorann said:

Not bad at all I think Wim, not even the first one looks particularly bad. So you have started using PS! Must be the layer thing that finally dragged you in. There should be some kind of solidarity data base for clear-sky-deprived astrophotographers, where those living in dryer areas can upload surplus data to keep us from going insane....

Now you got me mixed up with xiga, Göran. Unfortunately, I'm a lost cause. My transition to the dark side is complete: PixInsight and mono all the way.

The repository you're after exists as a yahoo group: Dslr astrophotography. I'm a member. Will look up and get you the link. It's moderated by Scott Rosen and Blair MacDonald.

Looked up:

https://groups.yahoo.com/neo/groups/dslr_astro_image_processing/info

@MarsG76: the clouds ARE global warming, imo. The higher temperature evaporates more water which enters the atmosphere and condensates as clouds. Global warming would need to go to insane levels to dry up all the water, and turn our planet into Mars.

[DaveS]

18 minutes ago, wimvb said:

 

@MarsG76: the clouds ARE global warming, imo. The higher temperature evaporates more water which enters the atmosphere and condensates as clouds. Global warming would need to go to insane levels to dry up all the water, and turn our planet into Mars.

And then we'd be complaining about the dust storms .

OK, back OT, they're not bad at all, especially from an un-modded camera. For some unfathomable reason I prefer the second image.

[gorann]

1 hour ago, wimvb said:

Now you got me mixed up with xiga, Göran. Unfortunately, I'm a lost cause. My transition to the dark side is complete: PixInsight and mono all the way.

The repository you're after exists as a yahoo group: Dslr astrophotography. I'm a member. Will look up and get you the link. It's moderated by Scott Rosen and Blair MacDonald.

Looked up:

https://groups.yahoo.com/neo/groups/dslr_astro_image_processing/info

@MarsG76: the clouds ARE global warming, imo. The higher temperature evaporates more water which enters the atmosphere and condensates as clouds. Global warming would need to go to insane levels to dry up all the water, and turn our planet into Mars.

I know I should not have replied to a post that early in the morning....... It all seemed very odd....

[lux eterna]

I am in the same situation as you Ciarán, resorting to old data and competing with my previous efforts. And sometimes it is well spent time, I will post here later.

I like the new background and star pattern being smoother and not so many tiny stars. Looks really good. The new nebula is also a winner, I like the colors and smoothness but still with preserved details. But then I think I prefer the wider FOV of the old pic.

Ragnar

[Xiga]

13 hours ago, DaveS said:

And then we'd be complaining about the dust storms .

OK, back OT, they're not bad at all, especially from an un-modded camera. For some unfathomable reason I prefer the second image.

Lol, seriously?!  Have you looked at both at 100% zoom? The original image was waaaaay over-processed. It just doesn't show up as much when viewed as a whole. 

11 hours ago, lux eterna said:

I am in the same situation as you Ciarán, resorting to old data and competing with my previous efforts. And sometimes it is well spent time, I will post here later.

I like the new background and star pattern being smoother and not so many tiny stars. Looks really good. The new nebula is also a winner, I like the colors and smoothness but still with preserved details. But then I think I prefer the wider FOV of the old pic.

Ragnar

You're right Ragnar, i should not have bothered trying to increase the image scale. The wide FoV would most likely have ended up looking better. I was just curious to see how a drizzled version would look so i couldn't help myself really.

The biggest improvement is in the background and stars (view both at 100% to see). The newer version doesn't even have any noise reduction done on it at all (apart from Noel Carboni's 'Less Crunchy More Fuzzy', which is very subtle), whereas i really went to town in the original version. 

Finally some clear skies forecast for Saturday and Sunday night here. Now if i can just shake this darn man/bird/aussi flu thing i might actually be able to take advantage of them...

[Xiga]

Here's a wee Photoshop technique i developed whilst processing this one. I consider it a form of Noise Reduction, although others may feel differently (i'll talk about that below).

So, being a DSLR user, our images often contain unwanted grain (aka noise). Small, randomly placed dark pixels that give the appearance of holes in our images. We often use Noise Reduction techniques to minimise these, but they obviously can only do so much, and in addition, they are a destructive technique. They actually remove detail, sometimes from areas we don't want it to. So what if we could fill in those holes instead? 

Now, this is the part that some might have a problem with. For some people, they might (rightfully) see this as unethical, as it is technically adding in information that was not captured. For others (including myself  ) who are just trying to reduce the noise in our images without getting caught up in the ethics of it all, it will be fine. So here goes...

First, i zoom into the problem area. Usually, this will be an area where there is a transition between nebulosity and deep space. The little black dots are most pronounced in these areas. So, i start by making a New Layer, then using the 'Quick Selection Tool' in PS (i just keep the default of 2 pixels), then i start to click on the small black pixel areas. I select about 20 or so, just to make sure i've got a decent sample amount. Then, i use Select->Similar, and let Photoshop expand the selection. Depending on the image in question, you might need to re-do the Similar command a few times or more. Then i do Edit-Fill (Content Aware) and drop the Opacity to something in the 50% region. You could also choose to expand and smooth the selection by 1 pixel as well before doing the Fill. 

Finally, use a Layer Mask to hide everything, and carefully use the paint brush (low opacity) to just fix the few small problem areas, but being very careful not to venture into areas that don't need it. So it's a very area-selective command, as you can do proper damage to your image if you aren't careful.

I've shown a quick before and after example below. As you can see, the impact is subtle, but does offer a nice improvement in smoothness. Hopefully someone else will find this useful. 

 

[lux eterna]

@Xiga I am with you, nothing unethical at all as long as you remove artifacts and not "real" details. In the examples above, I had to load the images on top of each other in PS to see the subtle difference, and I think you made some progress. But then there is a huge amount of noise left, and I can not see any details at all that deserves to be preserved, except for the stars and the slight gradients in colour and levels. So I gave it a try with a traditional NR :

I guess this is way too much for many people, and I accept that but I still can not understand why - as long as no visible "real" details are lost. The grainy pattern is non existent out there, so a more grain-less picture will be closer to reality I think.

Ragnar

 

[Xiga]

9 hours ago, lux eterna said:

@Xiga I am with you, nothing unethical at all as long as you remove artifacts and not "real" details. In the examples above, I had to load the images on top of each other in PS to see the subtle difference, and I think you made some progress. But then there is a huge amount of noise left, and I can not see any details at all that deserves to be preserved, except for the stars and the slight gradients in colour and levels. So I gave it a try with a traditional NR :

I guess this is way too much for many people, and I accept that but I still can not understand why - as long as no visible "real" details are lost. The grainy pattern is non existent out there, so a more grain-less picture will be closer to reality I think.

Ragnar

 

Hi Ragnar

I probably should have been more clear. The example images i showed above, were not final, or even close to final. They were in fact taken from a stack that only had a single stretch applied. I did this deliberately as i wanted the grain in the transitional area to show up the most. The rest of the image was not really part of the discussion. It is obviously much too noisy, as it had no processing applied yet. If you look at the final image in the OP, you will see that the noise is much less than it is in these examples. Sorry i wasn't clearer!

ps - These days i try my best to avoid doing any NR at all, or at the very least, as little as possible, but your image above with NR applied actually looks ok imho. :-)