Still haven't got my frustrated brain around DSS

[JR1987]

OK so the nights are getting longer and im finally able to go out and start imaging again.. I only started earlier this year, but I invested in the right gear and ive had some successful beginner sessions..

But my problems are when it comes to stacking. I really get so frustrated with DSS.. it just seems to ruin pictures and make them un-processable. 

All my images on the camera usually start off with a wash over them which with the single frames I can easily get rid of using white balance and levels in photoshop.. but Ive always assumed your ment to put the RAW files into DSS.. and when I do this, all the washes mix together and leave me with something that is just useless. In my initiative I feel I should be removing this before it go's into DSS.

This is leaving me ending up just processing single frames because that way I can actually work with the image, yet it just becomes noisy and rough looking.

here are some examples  

This is what my RAW files look like direct from the camera.. Around 3 mins in exposure

This is just playing around with a single sub for 5-10 mins in photoshop (at 1am before bed! I do have alot yet to learn) 

And this is what I get from my stacked lights, darks and bias from DSS.. an unworkable dark blob. 

I feel this is really holding me back in learning how to properly process... 

Any Suggestions??

Thanks

[StargeezerTim]

Not sure what is wrong. The autosave file from DSS is not finished by any means and often looks worse that the individual subs. But usually I find that with processing it contains much more than individual subs and can usually tolerate more processing as well. I think what I'm saying is that it is not supposed to look good at that stage but holds the potential for much better depth and detail than a single image once processed. 

Tim.

[kalasinman]

Briefly, don't do any processing prior to stacking.

Don't do any processing in DSS.

After you stack the first time click register again, then cancel. Go through the scres of your subs and take out the worst ones. I use thae register aboce..control and set it for what looks like an obvious point below the average of the higher scores. Then click on each sub and carefully evaluate them. There may well still be some bad ones in there. Then stack again. Minimise DSS and look for the Autosave1 in the file where the lights came from. Open this in your PS and do your stretch. You should be good from there.

[Marky1973]

Hi JR....I'm still trying to learn a lot, but this is my process with DSS. It might be that you need to tease out some detail in DSS and then move to GIMP or PS....or whatever you use....might not help, but Ryan it and see how you go....

https://markwalkerscreenwriting.wordpress.com/deep-sky-stacker-tutorial/

[JR1987]

Thanks guys. 

I followed your DSS guide Mark, and it did help with giving ideas of setting parameters etc.  I notice you do the small amount of processing in DSS too.. (it always confuses me when some people say you shouldnt touch that and others say you should..)

Perhaps I do have some bad subs in there.. 

Something I also thought I should show is the histogram of the stacked image once put inside photoshop.. It really does not look right to me at all and its probably the reason I cant seem to stretch anything out of the stacked image.

[Zakalwe]

Try this excellent tutorial

http://www.astrochat.co.uk/forum/viewtopic.php?t=13241

[cuivenion]

Try aligning the histogram in DSS once you've stacked. All the colours should be between center and left and lined up with each. It might take a bit of fiddling to get it absolutely right but even if you're close it should show a marked improvement. I would add that I'm no expert, this is what worked for me.

[Thalestris24]

Hi

I think after aligning the peaks in dss you could use the dss saturation tool to increase the colour saturation (try 20% to start). Then save the file as 16 bit tiff. Then you can post process using a curves adjustment tool. That should get you on your way

Louise

[JR1987]

Thanks for all the help guys.. its made a difference and sped up my learning.

I think ive started to work out my issues with it. I think I need to pay alot more attention to the scores in DSS, as I didnt realise I was putting in very low scores which were probably ruining the final image. 

I have also discovered I need to take a hell of alot more subs! 

[Marky1973]

Yeah, the professional view is no processing in DSS, but I find it helps me get started. But I'm a beginner, so need the help! I suspect, once my skills in processing improve I will change my process but, for now, it works for me. Taking the shots is easy I think... the real skill is in the processing...

[MattJenko]

... the real skill is in the processing...

It is also where the most fun is had in my view. Getting subs is very mechanical once you have a working system and then you just don't touch it all once imaging, so it is actually quite boring unless you like admiring your handiwork (and the marvels of modern amateur astronomy equipment) for a bit, which I admit is quite a good feeling.

[bruno]

As said align the peaks so theyr'e on top of each other, go on to the next tab slide the middle sliders to 39 & 5  then go into saturation and alter the slider to 18 & that should give you an image

[dph1nm]

That RAW picture is almost certainly not a linear representation of the true RAW from the camera. I am guessing that it has been scaled by some software to show it on the web. I would expect a true RAW to basically look black. The stacked DSS picture is roughly what I would expect it to look like. Don't think there is anything wrong with that. However that photoshop histogram looks like an 8-bit image to me, with an x axis range of 0-256, which isn't right.

NigelM

[JR1987]

However that photoshop histogram looks like an 8-bit image to me, with an x axis range of 0-256, which isn't right.

NigelM

Thats a good spot! I just opened the file in photoshop and brought up the info page and yea its 8bit.. I checked the raw files too.. they are 8bit! 

that must mean my camera (canon 100d) is taking them in 8bit?? I cant see anything in the menus of how to fix this. 

Possibly 'Aspect Ratio'?  it was set to 3.2... which doesnt seem right too me. shouldnt it be 16.9?

[Marky1973]

It is also where the most fun is had in my view. Getting subs is very mechanical once you have a working system and then you just don't touch it all once imaging, so it is actually quite boring unless you like admiring your handiwork (and the marvels of modern amateur astronomy equipment) for a bit, which I admit is quite a good feeling.

I agree, glad I'm not the only one...I have a tendency to take photos of the set up as well to look at....

[ollypenrice]

I wouldn't use DSS. That's the long and the short of it. It's slow and rather obscure. And you should certainly never process in it - at all.

I like to stack in AstroArt 5.0. Why? because it is lightning fast (seconds versus minutes) and this isn't so much to save time as to try alternative stacking algorithms. Try one set, save it, try another, find what works for your rig. You coud try five AA algorithms in the time it takes DSS to lumber through one.

If you are serious about imaging then Step Two is to go into Pixinsight and run DBE. This will do almost everything your stack needs doing to it in terms of gradient removal, colour calibration and balance, etc. You can also run SCNR Green at this stage and make life easier for yourself thereafter.

If you go straight into Photoshop (my Step Two) you could run the plug ins-Gradient Xterminator and Hasta La Vista Green (the latter being free.) Then, to align your colours, concetrate on the upper left of the histo peaks. These should be aligned. (A rule of thumb, but a good one.)

Olly

[Stub Mandrel]

Make sure DSS is saving 16-bit TIFFs, it had defaulted to 8-bit on mine so I was losing detail in the stacked images.

Neil

[Thalestris24]

Thats a good spot! I just opened the file in photoshop and brought up the info page and yea its 8bit.. I checked the raw files too.. they are 8bit! 

that must mean my camera (canon 100d) is taking them in 8bit?? I cant see anything in the menus of how to fix this. 

Possibly 'Aspect Ratio'?  it was set to 3.2... which doesnt seem right too me. shouldnt it be 16.9?

Hi

Were you taking subs in raw mode and stacking raw files (.cr2)?

Louise

[Marky1973]

I wouldn't use DSS. That's the long and the short of it. It's slow and rather obscure. And you should certainly never process in it - at all.

I like to stack in AstroArt 5.0. Why? because it is lightning fast (seconds versus minutes) and this isn't so much to save time as to try alternative stacking algorithms. Try one set, save it, try another, find what works for your rig. You coud try five AA algorithms in the time it takes DSS to lumber through one.

If you are serious about imaging then Step Two is to go into Pixinsight and run DBE. This will do almost everything your stack needs doing to it in terms of gradient removal, colour calibration and balance, etc. You can also run SCNR Green at this stage and make life easier for yourself thereafter.

If you go straight into Photoshop (my Step Two) you could run the plug ins-Gradient Xterminator and Hasta La Vista Green (the latter being free.) Then, to align your colours, concetrate on the upper left of the histo peaks. These should be aligned. (A rule of thumb, but a good one.)

Olly

I hate reading your posts Olly... they are far too knowledgeable and informative... so now I have to get hold of some new software and realise I have been "doing it all wrong" with DSS! 

Obviously that is because your posts are "bad" in the vernacular of the younger generation... which either means they are good, or I am about to be banned from this site...

[wxsatuser]

It is possible to do a rough stretch in DSS to give a quick and dirty image.

Make sure you have channels aligned when stacking and put a curve on the histogram like in the image.

You make the curve with the sliders under the luminance tab and whack the saturation upto at least 25%.

Save file with adjustments as a 16bit tiff, you can then tweak it in PS.

This is just 4 x 5minute subs of the Flaming Star.

[Thalestris24]

Hi

Just to add... When you stack with dss it creates an autosave.tif (or fits) file which is just the unadulterated stacked output. You can then align peaks and increase saturation and save the changes in a new file with a different name. As far as I know, I don't think doing that affects post-processing. Once you start stretching the histogram and saving that change then it will affect what you start with in a your chosen image processing software. But you always have the unchanged autosave file to go back to . I've had Pixinsight for several weeks and haven't done anything with it Yet! Must watch the tutorials I downloaded

Louise

[wxsatuser]

Normally I take the Autosave or a saved without adjustments tif into PI.

Generally in PI I first STF the image to see whats in there, then crop off the stacking artifacts.

Next hit it with DBE, SNCR and ACDNR.

Stretch the image but keep a smooth curve, no comb effect on the curve and make sure no or very little pixels are clipped.

[kalasinman]

Not necessary to manually align channels. Go to stacking settings, then result, check align channels. Automatic.

[ollypenrice]

If you do go for PI, a part of its genius is that it works on purely linear data for DBE (colour balance, background neutralization and gradient removal.) This is one reason why it beats all comers in these operations. You avoid stretching the image's errors before trying to get rid of them. Once they are stretched they are bound to be harder to eradicate.

Olly

[Thalestris24]

If you do go for PI, a part of its genius is that it works on purely linear data for DBE (colour balance, background neutralization and gradient removal.) This is one reason why it beats all comers in these operations. You avoid stretching the image's errors before trying to get rid of them. Once they are stretched they are bound to be harder to eradicate.

Olly

I'll have to watch the video tutorials soon!

Louise