deep sky stacker bug Luc Coiffier DeepSkyStacker (DSS) · Nikolaos Bafitis · ... · 22 · 490 · 0

Hello, every time I put in my images to be registered and stacked it says that only one out of all the images will be stacked, why is that?

It may seem obvious but.. did you select (check) all the images before to stack?

That's what I thought as well. From personal experience... 😬

One possible cause is that DSS cannot find enough stars to register the images.  Try lowering the star detection threshold to 2% under Register Checked Pictures -> Advanced.

If you have very few stars in the field of view, it might be possible that DSS still refuses to register your frames, so you'll need to use a different program for stacking.

so I tried everyhting but it still doesn't work so i'll just stack them in  siril

Tony Gondola:
Good move, DSS is not often used these days. Your time will be better spent learning better tools.

really?  What's the preferred tool lately? I've been out of the hobby for a bit so I'm out of touch perhaps.

Nikolaos Bafitis:
Hello, every time I put in my images to be registered and stacked it says that only one out of all the images will be stacked, why is that?

*DSS works really well in my experience, I have never had an issue using it. 

A quick tutorial:
-Click to open your image files. I use raw and fits, and it generally detects the image format well. If you see a weird bayer pattern, you can go the the raw/fits settings and set it manually, but again, generally not a problem.
-It helps to have darks and flats, but not necessary to stack. Load those if you have them.
-In the DSS file list, make sure all images, darks and flats are checked. Make sure the Type is listed correctly: lights, darks, flats, etc, just to confirm you loaded them. If you load darks as flats things are doing to go well.
-Click register checked pictures. In the Actions tab click autodetect hot pixels. In the advanced tab you can leave stack unchecked for now. Put the star detection at 2% (this means anything greater than 2% signal will be assumed to be a star. This is the most sensitive.  100% is actually the least sensitive. Click reduce noise by using median filter. If you don't get enough stars you can try this unchecked, but you may get noise counted as stars, so is a bit tricky.
-Click compute number  of stars. This gives you a rough estimate of stars. Normally it is easy enough to get 50 to 100 stars. I have managed with as few as 8 stars, but if your image is moving from frame to frame some stars may move out of the field. You need at least 8 stars in the field common to all images. Stars that are badly focussed (donuts) probably won't stack, and stars that are too elongated won't either. Finally very large size stars will not be used in stacking (not sure what the limit is maybe >10 pixels or so are too big.
-Click okay to register.
-Look at the FWHM to confirm that on average the stars are not too big. Look at the number of stars, are there enough stars registered. Often at this point I get rid of bad frames, you don't want bad frames in your final stack. Of course, also scan a few of the loaded images and make sure they look reasonably round. They need to be reasonable, not perfect.
-Now you can stack, and it should work fine.

One piece of advice though, if DSS won't stack your images because they are poor quality, don't find something that will stack them anyway. Find the problem with your images and fix it. Remember garbage in garbage out. For this reason DSS is a good program to stack, it requires at least some marginal quality level.

Finally, I do use DSS to take a quick look at the image stretch, it does have tools to do that, but it is hard to use for stretching.  If you have PS for processing you can start there, or GIMP is free and has similar tools to PS. I use StarTools, but not free. PI is the standard, but a steep learning curve in my experience.

Hope this helps
Rick

Sure it works, just pointing out that there are much more capable tools out there today, may of them free. Someone who has been out of the hobby for awhile might not realize how much things have advanced. I know it took me awhile to catch up, still am in fact.

Tony Gondola:
PixInsite for pay software, Siril for free. There might be others but those options will get the job done. There's also GraXpert for stretching, noise reduction and background extraction, free. Cosmic Clarity for blur exterminating and noise reduction, also for free. No matter what you go with you'll be well advised to top it off with a good Photo editing tool, Photoshop, GIMP and Affinity Photo are all good choices.

DSS does stacking.  It is not and does not claim to be an all-in-wonder tool like some of the other resources.  Of the resources you listed PixInsight and Siril are probably two other options that are good at stacking.  Affinity Photo also does astrophotography stacking (but it is a bit move convoluted than DSS, PI and Siril).  Some of the other resources you mentioned are tools for specific purposes and don't include stacking.  This thread was started concerning DSS and stacking so it's probably better to things such as GraXpert and CosmicClarity for another topic and keep this one focused on helping [url=astrobin-username=https://www.astrobin.com/users/Nick10/]Nikolaos Bafitis[/url] with DSS.

Have you checked out Groups.IO?  There is a dedicated group for DSS, https://groups.io/g/DeepSkyStacker  This is a good group and they are very helpful, I would recommend at a minimum checking out some of the FAQ and archives. 

One of the most important things to remember about DSS is that it's primary focus is deep sky image stacking.  I checked out your AstroBin gallery and notice that a lot of your images are Milky Way, Lunar, Solar and a few deep sky. 

I suspect that one of the issues that my be at play is non-round stars.  This is probably the #1 item that most beginners struggle with.  This is a common occurrence when using a camera tripod alt-az or an eq mount that is not well polar aligned.  DSS is expecting circular stars.  When the stars are trailed then DSS usually rejects them.  Zoom in on the stars in your image and make sure that then are round.  For a camera tripod or alt-az mount this will most likely mean that you need a shorter exposure so that the stars will stay round and not turn into ovals or trail.  If you are using an eq mount then work on improving your polar alignment.

A second common cause for stacking only 1 image is that DSS cannot find enough common stars.  The requirement is that DSS needs 8 common start for all images.  DSS also has an upper threshold of 100 stars, it will detect more than 100 stars but only up to 100 stars will be used.  If DSS is detecting +1000 stars it is highly likely than DSS is detecting hot pixels and/or noise as stars.  Some good suggestions have already been given for increasing the number of detected stars. 

A third issue is that you may have the number of frames to be stacked set to a very low percentage.  This is not usually the problem, I think the default stacking percentage is either 75% or 90%, I'm not exactly sure but I do know that it is not 100%.  The reason this is not usually the problem is because in order to stack only 1 frame you would need a very low number of frames and have the stacking percentage set to a ridiculous low number...say stack the best 1% of 100 frames, which would be only 1 frame but realistically almost no one would do that.

Additionally, if you could provide some images the produce the problem then those with DSS experience will be better able to help you with troubleshooting and understanding the problem.  Usually that would mean a few light frames, a minimum number that would reproduce the problem.  In the case of only stacking 1 frame, you might need to provide 3-5 light frames that would generate the message that only one frame will be stacked.  Calibration files are also useful, especially if the problem is related to calibration.  In your current case, it sounds more like a light frame image quality issue so you probably don't need to supply calibration frames.  Usually the best way to share images is to use a file sharing service such as Dropbox, GoogleDrive, OneDrive or similar. 

Finally, other resources have been mentioned that can be used.  Some of them, especially the free options are much more liberal with the shape of the stars.  If you have a wide field of view such as Milky Way then those options would probably be the better choice because it is highly likely that the images will have some degree of oval/trailed stars.  When it comes to stacking deep sky images, round stars are essential to good quality and high resolution.  A lot of times when DSS has a message that it will not stack all the frames you choose, it is because DSS has determined than the stars and other parameters such as sky background and image quality are poor.  Stacking a lot of poor frames that have low quality stars will not magically make them round and produce a POD quality image. 

Personally, this is what I do.  1- I first add all my light frames and check them all.  2- Then use the first frame in the list to set the star threshold, adjust this so that 20-100 stars are detected.  The reason to shoot for a minimum of 20 stars is to ensure that the criteria of "8 stars in common across all frames" is more likely to be met.  Try and keep the total stars under 100, but in some cases that is not possible, especially if the image has lots of stars.  3- Resister the images.  This is the process that DSS uses to calculate star/image quality, determine the star locations, calculate FWHM and sky background.  4- After registration, check the images that DSS has chosen flagged with low number of stars, low quality score, high FWHM and high sky background.  You will likely find that frames that DSS has calculated to have low quality will indeed be frames than have problems.  Problems my include trailed stars due to poor tracking/guiding, high background due to clouds or LP.  5- Uncheck (or remove from list) any of the low quality images before stacking.  6- I often prefer to take my first run at stacking using only the light frames.  This allows me to see any problems in the image.  With some of the latest dedicated astrophotography cooled sensor cameras there is almost no amp glow and almost no dark current (example ASI2600, ASI553).  6- If the initial stacked image looks good then I will go back and restack using a full set of calibration frames.

Mike Jaworski:
The list of pixinsight and siril are what we're also alternatives a few years ago.  Looks like the landscape hasn't really changed, if I'm being honest.

Doesn't a-bin have metrics on how many users are posting with DSS?  I've never dug into it but I thought it had options for data mining.

Mike,  You are correct.  For full transparency, I don't use either PixInsight or Siril.  I'm not trying to say they are not good programs as they are quite excellent, especially when looking back over the past nearly 15 years that I've been astro imaging.   PixInsight is by far the top choice.  There are those with limited budgets (or other reasons they my not want to spend the $$$ for PI).  Siril is probably the top choice for free programs.  There are many other examples out there.  I have been using Affinity Photo, a lot of the current plug-ins for Photoshop also work in Affinity Photo.  As AstroBin has improved a lot of features have been added, including the ability search/data mine.  I really don't use data mining options much but agree, it would be interesting to see what programs are being used.  I'm not sure if AB would break it down by category such as stacking, processing, noise reduction, etc.  Some programs (PI come to mind) have their own built in things like stacking, stretching, noise reduction, ect...but at the same time PI also has scripts and plug-in that allow some of the 3rd party apps/programs to run withing the PI environment/program which might skew the data slightly.  Either way, a data dive into processing programs used in AB might be interesting.

John Schnupp:

Tony Gondola:
PixInsite for pay software, Siril for free. There might be others but those options will get the job done. There's also GraXpert for stretching, noise reduction and background extraction, free. Cosmic Clarity for blur exterminating and noise reduction, also for free. No matter what you go with you'll be well advised to top it off with a good Photo editing tool, Photoshop, GIMP and Affinity Photo are all good choices.

DSS does stacking.  It is not and does not claim to be an all-in-wonder tool like some of the other resources.  Of the resources you listed PixInsight and Siril are probably two other options that are good at stacking.  Affinity Photo also does astrophotography stacking (but it is a bit move convoluted than DSS, PI and Siril).  Some of the other resources you mentioned are tools for specific purposes and don't include stacking.  This thread was started concerning DSS and stacking so it's probably better to things such as GraXpert and CosmicClarity for another topic and keep this one focused on helping [url=astrobin-username=https://www.astrobin.com/users/Nick10/]Nikolaos Bafitis[/url] with DSS.

The original poster did ask the question so I answered. I don't see why that's an issue.

It shouldn't be. I know a lot of people still use it, probably out of habit and that's fine but I stand by what I said, there are better tools out there IMO.