Deep Sky Stacker Problem Luc Coiffier DeepSkyStacker (DSS) · Alien_Enthusiast · ... · 7 · 372 · 2

Alien_Enthusiast 2.11
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Dear Astrobinners!

Im having problems with my DSS registering frames.

I have 4 channels, LRGB. 

First I stacked the luminance frames, and DSS did it with no problem.

However when I got to Red, it wasnt able to compute offsets, or to be exact it did, but no data was put into the X/Y shift table.

After, when I tried stacking, it showed me this warning:

Снимок экрана 2023-12-15 131141.png

I tried raising detection threshold to 98% - no luck. Still the same thing.

I will also attach the screenshot of the reference frame, where you can clearly see 2 stars even without any streching.

Снимок экрана 2023-12-15 131202.png

How do I get DSS to stack my data?

Any help would be greatly appreciated!
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StellarSilence 0.00
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·  1 like
Reduce your detection threshold. The lower the number, the more stars detected.
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HotSkyAstronomy 2.11
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·  2 likes
Evan Drew:
Reduce your detection threshold. The lower the number, the more stars detected.

This and up the brightness in the RAW/FITS DPP settings
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rveregin 6.76
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·  3 likes
Evan Drew:
Reduce your detection threshold. The lower the number, the more stars detected.

Yes, going to a higher % is the wrong way.

Just to add to your comment Evan.

The threshold is the minimum signal (as a % of full well) that will be detected as a star. So for example if you look at the DSS background % when you register you might see say 2%. Star detection threshold must be above that, otherwise you might count background noise as stars, which would be bad. But if you set the threshold too high you won't get enough stars. You want to set the threshold so you ideally get at 100 stars registered, so I try to lower the threshold until I reach about 100, again as long as it is not lower than the background level.

​​​​​​​DSS will stack as long as it can find at least  about 8 good stars in all the frames that are above the threshold, less than that and it won't be able to compute offsets. I find generally a good number is between 2% and 10% for the threshold. Again, lower it to maximize the stars as high as possible, but don't go too much over 100 stars. When you set the threshold you normally click the box in that advanced tab to filter noise. But if at 2% threshold you still don't have enough stars you can unclick the noise filter. Sometimes this helps.

Rick
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rveregin 6.76
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·  1 like
Evan Drew:
Reduce your detection threshold. The lower the number, the more stars detected.

This and up the brightness in the RAW/FITS DPP settings

Yes, I have used this  brightness trick in the past as well, it can help if all else fails, so great to use it if needed. One caveat is to register the stars with the higher brightness to get more stars, but when you stack, go back to the default setting. I saw horrible color shifts in the past if I left DSS on high brightness, it is somehow stretching the image. Anyway, once the stars are registered okay, it is easy enough to set the brightness back to default for stacking. DSS uses the registration info to create the offsets, so once everything is register okay, the stack will work fine with the default brightness.
Rick
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HotSkyAstronomy 2.11
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·  1 like
Rick Veregin:
Evan Drew:
Reduce your detection threshold. The lower the number, the more stars detected.

This and up the brightness in the RAW/FITS DPP settings

Yes, I have used this  brightness trick in the past as well, it can help if all else fails, so great to use it if needed. One caveat is to register the stars with the higher brightness to get more stars, but when you stack, go back to the default setting. I saw horrible color shifts in the past if I left DSS on high brightness, it is somehow stretching the image. Anyway, once the stars are registered okay, it is easy enough to set the brightness back to default for stacking. DSS uses the registration info to create the offsets, so once everything is register okay, the stack will work fine with the default brightness.
Rick

Absolutely! Thats what I do.
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Alien_Enthusiast 2.11
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·  2 likes
Thank you all for the help! I reduced it to 2% and increased brightness to 1.9 and it worked perfectly! Fellow AstroBinners never disappoint.
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HotSkyAstronomy 2.11
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·  2 likes
Alien_Enthusiast:
Thank you all for the help! I reduced it to 2% and increased brightness to 1.9 and it worked perfectly! Fellow AstroBinners never disappoint.

That's why I got a subscription. It's such a good service that I gain so much out of that throwing money at it seemed appropriate 
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