Deep Sky Stacker only stacks 29 frames instead of 300!

[SeBasstian]

I have a huge problem with DSS.

About a week ago, I took 300, 2 second long exposures of Andromeda with my skywatcher 90/900.

But when DSS started scanning the stars in the images, it only registered about 5 stars at 40%. And only 7 stars at 20%. I tried to stack them and selected stack 100% of frames, but it only stacked around 29.

I even tried it at 4% where it registered around 40 stars, but DSS crashed mid process due to the immense amount of stars being scanned (60 000 per image at least). 

I tried it sooooo many times, but I don't get it to work. It somehow stacked 131 images I took of the lagune nebula (1 second lang exposure). You couldn't see the actual nebula, but some bright stars were there and DSS was able to stack. 

In the Andromeda pics, there were like 5 times more stars, but it didn't work. 

If anyone knows what's wrong, pls help me!!! I'm slowly loosing it on that nonsense. 

[gilesco]

I'm not a huge expert, but would suggest that you take longer exposures even though you'll get fewer in the time. Appreciate you're trying to avoid washing out Andromeda, but you need longer exposures than 2s, otherwise you're just compounding noise on more noise?

[SeBasstian]

2 minutes ago, gilesco said:

I'm not a huge expert, but would suggest that you take longer exposures even though you'll get fewer in the time. Appreciate you're trying to avoid washing out Andromeda, but you need longer exposures than 2s, otherwise you're just compounding noise on more noise?

Thanks for the reply! One problem is, that I don't have a tracking mount. So I can't take more than 2 second exposures. And there are several bright stars visible in the picture. I think the problem lies within DSS that it can't find enough stars in most of the images, although there are some beight ones very very noticeable. 

But as soon as I get a tracking mount, I'll start tanking longer exposures. 

[Seelive]

DSS will not stack images where the stars are out of focus or trailed or just too large. It also needs a minimum number of 'valid' common stars to be present in each image (I believe the number is 8). So counts of 5 or 7 are too low. When the threshold is reduced further and you get a sudden huge increase in the number of stars detected, you are infact just detecting noise so make sure the median filter is enabled.

[SeBasstian]

5 hours ago, Seelive said:

DSS will not stack images where the stars are out of focus or trailed or just too large. It also needs a minimum number of 'valid' common stars to be present in each image (I believe the number is 8). So counts of 5 or 7 are too low. When the threshold is reduced further and you get a sudden huge increase in the number of stars detected, you are infact just detecting noise so make sure the median filter is enabled.

Thanks a lot. I'll go try it out now.