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**Space*Hopper**

Silly problem with DeepSkyStacker - help needed please

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Hi all,

Recently I purchased a C8 SCT from a fellow SGL member and last night I used this to capture 38 x 30 sec subs of M3 + 8 dark frames.

I have been using DSS for a while now without any problems but last night I started it processing my M3 files and then went away to do other things while it worked its magic. I then loaded the resulting image into Paint Shop Pro for processing and was horrified that the image looked terrible and not a patch to last years result from my Skywatcher ED100 Pro and I simply could not work out why this was as the subs looked pretty good to me. Anyway tonight I thought I would refine the selection of subs down to the very best and have another go at processing them and as a result of this I have found out why the resulting image looked so bad.

DSS calculated the master dark, registered the correct total amount of light (image) frames, and then proceeded to stack 1 of 1 :) Whatever selection / quantity of picture subs I used it only ever stacked 1 of them ! No wonder the resulting image looked so bad :)

Has anyone ever come accross this before and what do I have to do to sort it please ?

As always, thanks in advance

Ian

Edited by **Space*Hopper**

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Yes. DSS couldn't detect enough stars.

If you go to the Advanced tab, after selecting Register Checked Pictures, there you can alter the star detection theshold. The lower the threshold the greater the number stars detected.

Maybe.

Steve

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Thanks Steve,

I increased it from 10 to 11 and now it is stacking many more frames but the resulting image appears not to be stacked as such.

Where as my previous image stacking projects have resulted in a pile of images which did not overlap exactly to keep their individual contents exaclty aligned, the result of the stack that I am now getting for this project is all over the place and it's as if each frame has been placed on top of the others without any attempt to align the images. I think I must be missing something yes ?

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err... to detect more stars, you need to move the slider DOWN (so the percentage value goes down)

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Ok - understood thanks and it is certainly detecting more stars now.

However - the stacked images are still all over the place and are not in any way aligned :)

I sure hope this image is going to be worth all this :)

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manually check each and every frame, make sure none of them are "all over the place" to start with. deselect any that are "bad"

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The individual frames are fine, no worse than I have stacked many times before.

All my previous stacking projects have ended up in a stack of images all of which overlapped to various degrees at the edges in order to keep the image of each sub correctly aligned with each other. i.e the image subject is correclty aligned even if the total area of each subs frame is not.

For this project however it's as if DSS is taking a pile of 6" x 4" photos and placing them in a neat pile exaclty on top of each other without even trying to align the image contained on each. Sorry but that is the best I can explain it.

****Have now added a picture of 6 stacked subs, as you can see DSS has made no effort to align the images****

post-14420-133877361285_thumb.jpg

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It looks to me like theres too much trailing on the stars so they aren't being detected as stars ... DSS needs pretty round stars to work...

Post a single sub up so we can have a look?

Billy...

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I will glady post a single sub but I have already weeded out the worst and have successfully stacked far worse before as for previous projects I usually do 2 x stacks - 1 with all the subs no matter how bad they are and 1 with just the best of the subs.

****screendump jpg copy of a sub now added****

post-14420-133877361296_thumb.jpg

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is that a good one or a bad one... looks like a good one to me...?

If all else fails manulaly select a few stars and stack that way...

Billy....

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It is indeed a good one but the ones I am trying to stack now are all similar to that which is why this whole situation makes no sense to me at all. It's almost as if DSS has broken in some way.

I have now uninstalled it and installed the newer version 3.2.2 but that made no difference :)

I think this M3 has the potential to be my best to date but this inability to process it really sucks :)

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If all else fails I'd go with manual star selection and use the three stars in the large triangle around M3... they are far enough apart to do a pretty good job...

Billy...

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I had exactly the same problem with DSS stacking my M3 shots. I ended up setting the detection threshold to 2, and setting the options in register to stack automatically with 100% of the frames. That did the trick and instead of stacking 1 it stacked all 11.

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Sorry to be a pain but is that easy to do ? (I have no idea).

Can't believe this is proving so difficult :)

****Sorry - this is in response to Billy's post about manually selecting the stars****

Johns I understand and will give a go 1st though - however it is now stacking all of the subs but just not aligning them :)

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click on register checked pictures, advanced, move the slider till the value reads 2%. Back to the first tab, tick the box at the bottom that says to stack after registration, type over the 80 that's in the box and make it 100. I got to that by mucking about with the settings till I got all the frames to stack.

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Ok - stacking the subs is no longer a problem but DSS is not making any effort to align them. Here is the latest attempt using 3 of the subs as a test with Johns settings, (found so many stars it took ages lol).

I cannot for the life of me understand why it has done all my previous projects but is having so much trouble with this one.

But moving on.................

How do I do the manual star selection please ?

Or is there a better program to try ?

post-14420-133877361302_thumb.jpg

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Come on please guys this is driving me nuts :)

The 1st DSO I have tried with my new C8 and DSS can't cope with it, it's not a promising start :( I have just tried some of last years subs from my ED100 and they are still stacking fine so I guess DSS is still working, (but just not with subs from the C8 :)).

If nobody has a solution, maybe I can upload the subs somewhere for some other kind person to have a go at stacking ?

What do you think please ?

Looking at the subs I think this promises to be my best M3 to date so you can understand my frustration :(

:D Please someone help :)

P.S. I have tried but am honestly not sure how to do the manual star selection thing - sorry :)

Edited by **Space*Hopper**

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As you say, it's probably a good idea to post some subs up so that we can see the problem first hand.

Steve

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Ok guys,

Below are the links to 10 of the subs. If anyone can successfully stack these I will then post the remaining subs along with the associated darks, (always assuming that they are happy to stack the whole lot for me).

Once stacked if they could then post a link to the resulting file I will gladly process it from there.

Also if someone does manage to stack these and has got any idea as to why I cannot, I would be very grateful for some guidance as to what I am doing wrong.

Thanks & fingers crossed

:)

Ian

Just right click and "save target as"

Image3776

Image3767

Image3765

Image3760

Image3754

Image3752

Image3750

Image3744

Image3742

Image3738

Edited by **Space*Hopper**

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I think I might be onto something here.

I have found the manual star selection tool but it does not recognize the main bright stars as stars and will therefore not let me select them. It looks like the 2000mm focal length of the C8 has made the stars too big for them to be clased as stars :D

That got me thinking that maybe if I resized the images to make the stars smaller, maybe they would then be recognized as stars. So I have just resized 20 subs to 50% of their original size to test this theory and sure enough they stack perfectly :) However 90%, 80%, 70% or even 60% of the original image size still causes problems.

Surely reducing the image size cannot be the only way to resolve this can it ? If so then it kind of defeats the whole point of buying a more powerfull scope :)

Please therefore keep trying to stack the 10 original size subs as I would love to know if this is possible and if so, how :)

Thanks

Ian

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I have resized 34 subs and 8 darks to 50% of their original size and they have stacked fine :) I am tired now and need to go to bed but just had to have a quick go at processing so here is the resulting image, (resized by a further 50% height + width to get it within limits for the forum). I know I have over-cooked it a bit and have not yet cropped off the frame stack overlap from the edges of the image but I am convinced now that this is definitely going to be my best ever M3 and I will no doubt have another go at processing it tomorrow when I am more awake :(

If processing subs resized to 50% looks this good, (in fact they are resized to 50% height and 50% width so they are only 25% of the original size :)), just imagine what it would look like if I could find a way to process the full size versions :)

Anyway the extra light grasp of the C8 over my ED100 is clear and I am a lot happier now I know that at least the subs are ok and the reason why DSS is not processing them in their original form.

Please, please, please do keep trying to stack the full size versions I have posted above as I am still very eager to learn how this can be done and see the full size result :(

If I manage to process a better version tomorrow I will of course post it :D

Goodnight all :)

post-14420-13387736159_thumb.jpg

Edited by **Space*Hopper**

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There may be some truth in that Billy.

But all I know is that I have previously successfully processed many stacks from my 900mm focal length ED100 with far worse stars than these, so the extra magnification from the 2000mm focal length C8 must definitely be a contributing factor.

Anyway at least I now have an image to show for my evenings work and fingers crossed, someone will find a way to stack the full size subs :)

Thanks for all the help so far guys :)

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Lo Ian

Just noticed this thread so here's a question for You, are all your subs taken in JPEG's or are You converting from RAW's. Sometimes DSS has a problem with artifacts in jpg format images. :)

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Interesting point thanks Kev,

They are all JPEG's as that's what I have always used in the past without ever encountering this problem, (however this is the 1st DSO I have taken with the C8). If no one manages to stack the full size JPG subs then maybe I will give the RAW format a go on my next project to see if the problem goes away.

:)

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