TheSkySearchers

eGood day all!

I've been fortunate enough to get out and do some imaging lately (weather cooperation) and my targets are in very "busy" parts of the sky.
The Milky Way is pretty densely packed! There's a TON of stars in there and I'm afraid it makes my images look "busy" for lack of a better term...

I've seen WAY better images of these targets than mine and I'm not sure what I'm doing wrong...

I'd appreciate any thoughts on how I can clean these up a bit.

Stacking in DSS
I'm using a "cookie cutter" approach in StarTools because it''s pretty powerful software and it's over my head...
Finishing touches in GIMP

Here's a few of my latest attempts...

Thanks for looking!

Larry

Nice images, Larry, congrats. I won't be much help with this as I like the full effect of the surrounding stars. Others will be along with suggestions for you. Keep on imaging!

Bob

Thanks Bob!
Maybe if I could clean up some of the halos around the bright ones?
I don't know... There's something I don't like and I'm not sure what it is...

Larry

They do look busy and expert responses will be interesting but they still look pretty good I would say.

The Western Veil is really good.

Regards

Graem,e

I think the images are really good, especially the last two and they get better as they go. It'd help to have the details of the capture since that influences how good an image looks.

That said, I've seen experts take single exposure shots of relatively bright targets like the Veil and make it shine - 80-90% of what they themselves could do with a lot of data. Since I'm not at the level yet I've found there's no substitute for capturing a lot of data, the better the quality the better it is but good processing tools can sort it out. If you do that then you can get to the close to where the experts are with little processing effort sometimes. But in the end, if you want to eke out that final 10-20% edge you have to get good at both presumably.

Also stars can get in the way of showing the object but there are tricks to tighten star edges (Nebulosity) or reduce star sizes that can be tried to keep the stars but don't highlight them.

--Ram

I won't presume to offer expert advice, but you could separate the stars and target, process them individually, and then recombine them and adjust the level of "star-age" to your preference.

On this forum Steve has had some great posts about using a defect map (PixInsight)to remove stars, but the stand-alone software StarNet does so too.

I find the starless images very intriguing. Here's one of mine of the Eastern Veil.

ram wrote: ↑Mon Jul 20, 2020 12:02 am I think the images are really good, especially the last two and they get better as they go. It'd help to have the details of the capture since that influences how good an image looks.

Thanks Ram!
The Wizard is 2.5 hours on target (clouds rolled in last night). 180" exposures at gain 0 and offset 65 with a ZWO ASI 071 MC Pro.
The veils are about 5 hours each with darks, flats and dark flats from bortle 6 skies...

I try to get at least 6 hours on target because I do find the data easier to process.

Larry

DEnc wrote: ↑Mon Jul 20, 2020 12:07 am I won't presume to offer expert advice, but you could separate the stars and target, process them individually, and then recombine them and adjust the level of "star-age" to your preference.

Thanks DEnc!

I'm on the fence about starless images. (Yours is pretty cool though ).
I'm also afraid it's time to try to get my processing game up to the next level...
I really don't want to learn all of this, but it looks like I'm going to have too...

Larry

Larry 1969 wrote: ↑Mon Jul 20, 2020 12:43 am I'm on the fence about starless images.

But they can be useful processing intermediates, don't you think? Once you have the starless and targetless intermediates in hand, there's more freedom in enhancing each to their best, before combining them for the final image.

I've enjoyed some threads in other forums about what's "real" in astro-imaging. This approach certainly gets caught up in that!

DEnc wrote: ↑Mon Jul 20, 2020 12:48 am

Larry 1969 wrote: ↑Mon Jul 20, 2020 12:43 am I'm on the fence about starless images.

But they can be useful processing intermediates, don't you think?

I do...
I'm just trying to avoid all of that processing hassle...
Separating images and then re-combining them...
I'm not sure if that's within my skill set.
I may have to step up my game!

Larry

Larry 1969 wrote: ↑Mon Jul 20, 2020 12:40 am

ram wrote: ↑Mon Jul 20, 2020 12:02 am I think the images are really good, especially the last two and they get better as they go. It'd help to have the details of the capture since that influences how good an image looks.

Thanks Ram!
The Wizard is 2.5 hours on target (clouds rolled in last night). 180" exposures at gain 0 and offset 65 with a ZWO ASI 071 MC Pro.
The veils are about 5 hours each with darks, flats and dark flats from bortle 6 skies...

I try to get at least 6 hours on target because I do find the data easier to process.

Larry

The TOT I think makes a difference but you're also dealing with other issues IMHO. Bortle 6 skies combined with a OSC I think makes it difficult for you though your OSC is very good, about as good as you can do with an OSC but it is not being used at a dark site and you're choosing to shoot nebulae which as you noticed lie in our own galaxy in fields of stars so you're going to be in a fight between the light pollution and stars. For nebulae, if you went NB I think you'll get to the quality you want easily. In fact, I believe if you just used a Ha filter, you would see a remarkable difference. Not trying to convert you (I think you mentioned you didn't want to deal with that also in another thread) but just explaining why I got into AP in the first place (I started with low res OSC/mono shots with large pixel cameras for EAA but it was NB that changed me into a APer).

Most of the high quality images you've seen I'm sure are based on NB or some sort of filtering for OSC that mitigates light pollution OR doing it at a dark site. I think given your constraints these are really good images.

That said, I think "stepping up your game" in terms of processing may end up becoming necessary - after all, the point is to grow right? I used to be very happy with my 30 second frames on a 0.5 mp camera taken quickly (I'd do like 10-20 targets per night!) and some of those images even turned out "okay" but no match for the higher resolution images.

You do have that nice camera so I think the best results you'll get in your situation is likely with galaxies and reflection nebulae like M45, Cocoon, etc. Just my very humble opinion. Have you looked at M31 and M33? Your camera would do amazing work on those...

--Ram

Hi Larry,

If you're using StarTools, the Life module gives you a few ways of pushing back busy star fields and re-focus the viewer's attention on the larger scale structures. Try the Isolate preset (w/o mask), or try the a tweaked version with Parameter [Detail Preservation] set to [Min Distance to 1/2 Unity]. You can even run two iterations (a combination of the two ) if you want;



Note that the above techniques do not use star masks at all.

You can, of course, also use techniques to manipulate the star shapes as well (these technique do use a star mask), for example by using morphological filters (as found in StarTools' Shrink module).

Being more careful with how your processing decisions affect the prominence of stars in the first place is usually the key;

• avoid stretches that bloat stars (for example, don't use a manual Develop in StarTools)
• use star masks if you don't want to see stars processed; StarTools can auto-generate these for you whenever you need them (for example mask out stars when using wavelet sharpening if you don't want this procedure to affect your stars)

More generally speaking, unless your tools are somehow incapable of dealing with stars, I cannot think of a valid reason to separately process stars and background. That's because this procedure, by definition, will yield artefacts if processed separately; data needs to artificially manufactured for the pixels that used to take up the full stellar profile. It tampers with the point spread function in your "starless" image, while the synthesized detail will affect the outcome of any algorithm that relies on spatially co-located pixel analysis (e.g. algorithms that "scan" the neighborhood). Most detail restoring/enhancing algorithms fall in that category. The effect may be more or less pronounced, but it will be there. Depending on whether you are a purist, relying on "made up" data may be objectionable. As a developer I would leave that decision to the user (there is a guide for using StarNet++ with StarTools here if you want for example), however when publishing an image, I, for one, would certainly want to know about any treatment that completely made up data. Sadly (fortunately?) I can usually pick such a treatment quite easily, but others may not.

If you don't have tools to generate accurate masks easily (e.g. you use the GIMP or Photoshop for example), something like StarNet++ can definitely be useful for the generation of masks - if you really don't have anything else. Its output is unfortunately only as good as the data it was trained on; YMMV heavily depending on how you stretched your image and what point spread function your optical train produces.

Hope any of this helps!

Thanks Ram!
I did mention in another post that I wasn't ready to take the plunge into mono imaging just yet. I want to get as good as I can with OSC for now.
You're right about target selection. I will be spending time on M33 for sure but M31 is way too big for my 840mm focal length.

Larry

Thanks Ivo!
I normally start with auto dev and keep. Then bin 50% and keep. Crop, keep. Wipe, keep.
I usually then do another auto dev with a slice of ROI and keep but I found that to look over developed so I did do a manual develop.
If I were to do another auto dev, what would you suggest for my ROI? I just used a slice of the nebulosity...

Larry

I happen to like the "busy" images. They look a lot like my own. They really show how many stars there are in the galaxy. The middle one of the Veil is really splendid and looks like one of my own.

Your above sequence is almost the same as mine. On nebulae I do autodev, wipe (to find where I need to crop), undo the wipe, crop the image, wipe - I use a 2 pixel dark, then manual dev until I like what I see. Generally I error on a little more brightness knowing that contrast, noise reduction, etc will clean up and darken the image background.

So I really do like the middle image... but beauty is in the eye of the beholder.

Larry 1969 wrote: ↑Mon Jul 20, 2020 10:46 am Thanks Ram!
I did mention in another post that I wasn't ready to take the plunge into mono imaging just yet. I want to get as good as I can with OSC for now.
You're right about target selection. I will be spending time on M33 for sure but M31 is way too big for my 840mm focal length.

Larry

I'm not sure if your 8" fields a reducer but that may be worth considering - if you can reduce by 30%, that puts you at ~600mm.. but M33 is a good target as well. You also have a nice big sensor size with the camera...

--Ram

Thanks Star Dad!
I ran into some trouble using the wipe module before the crop in the past. It might no be as bad now that I'm using the "Intersection" mode in DSS rather than the "standard" mode...

How did you come up with a 2 pixel dark anomaly filter? I've been using 5 because it was suggested by someone here. Just curious how it works.

Maybe this "busy" stuff will grow on me, but for now it flares up my OCD!

Larry

I also used for 5 for a long time. 1 does not work for me - at all. I tried 2 and lo and behold the image was vastly improved. Well, as I type this I also just realized that I made the switch from 5 to 2 when I stopped using the Canon 70D and shifted to the ASI294MC cooled. I recall trying various settings and 2 seems to be perfect for the 294. Unfortunately, StarTools doesn't explain a lot of the underlying math involved, and the limited help is mostly useless. I started out doing what many tutorials say to do, but when I get an image that is not satisfactory - or what I think it should look like then I begin to tinker with settings. But it's mostly guess work. I wish there were better explanations for each of the "steps" i.e. contrast, demosaic, life, etc do and what changing the values really does. For instance what does the difference in structure size really mean and when should I apply one of the three choices?

Larry, those are stunning images... The Veil in particular.

I took the liberty of throwing your image of The Veil into Photoshop to see what I could do with the stars. I put a feathered mask around The Veil and adjusted the histogram to dampen the brightness of the surrounding area.

(I'm a solar imager and haven't shot a DSO since moving to Las Vegas ten years ago.) LOL

Hi Larry - You have received a lot of feedback on this topic. My approach was to remove the stars, reduce the stars brightness, then put the stars back into the image. The result is below.



The reduced stars certainly allow the low-level nebulosity and details of this beautiful nebula to show through better (IMO). By the way this was done using PIxInsight.

Nice work.

Steve