DSS wont stack

[jimmyh1555]

I just took 20 lights DSO with my ASI183 (35sec each saved as .fits)). put it through pipp, then tried to stack in DSS I checked the 20 lights then pressed "Register" It whizzed away then message came up "Only 1 frame will be stacked. Check above a threshold."
I clicked the check above threshold button tried all sorts of numbers (1,99,0,25,50) Nothing worked. What's going on? HELP:help: There were not many stars in the picture, but when it was whizzing away, I saw that DSS had found around 57 stars. Any ideas?

[RyanJones]

Hi James.

There are a couple of different things that could be causing your issue.

When you go into register, click on the advanced tab. Adjust the star detection threshold down to the lowest percentage. This will allow DSS to pick up more stars. It needs a minimum of 8 clean stars to stack on every frame. You said it picks up 57 stars so this may not be the issue but it's worth a try.

The other thing you can do is below the register button there is one that says compute offsets. Click this and it will register all of your frames and based on the quality of each frame, it will give each frame a score. The highest scoring frame will become your reference frame by which each following frame is stacked. This is where check above threshold comes in. You pick what the lowest score you want to use is and it will ignore everything lower. You may find when you do this that DSS will not come up with a score or calculate the offsets and rotation angles for some frames. This is because the quality of the stars is not good enough to be able to align it. If that is the case, then it's back outside to have another crack. :))

I hope this helps

[bojan]

James,

Why do you use pipp, DSS should deal with many image formats directly (Canon, Nikon, whatever).


I had stack problem only once couple of years ago, when I tried to stack a comet... there were not many stars in the frame.. but I forgot what was the workaround.

[Gavin1234]

Were you imaging helix?

I’ve found that helix sometimes causes that problem in DSS because of the lack of stars in an unstretched image. Set star detection threshold to the lowest possible.

[jimmyh1555]

Thanks, guys! I just wrote a long post and the bloomin' thing crashed! Anyway, I found the threshold setting it was 10%. I lowered it ti 2% and it worked!
Also, Bojan, why do I use Pipp? Don't know! Somebody on this forum said to use it to sort out the debayering. What is it supposed to do?

[bojan]

It is used for image conversion.. usually to convert the stack produced by Autostakert (planetary work).


I don't think it is really necessary here, especially when you are still learning.