problem with DSS

[rikyuu]

hi, I was hoping someone could help please;

I'v found in DSS that I can't always get it to stack all the subs I've selected. Even though they are selected, and I've opted to stack 100%, for a particular set of subs it may only do 2 out of the 6 for example. I can move the 6 subs to a different directory, but it will only do 2 of them, and it's not even the 2 with the highest score either! So I've got 30 minutes of data on the Dumbell, but it will only stack 2 subs which is 10mins.

But on another DSO, it will do all 6 subs with no problem. I have tried all the different stacking methods, but the issue still exists.

I must be missing something obvious, can anyone advise please?

Thanks

[rikyuu]

ps. I also tried it on my other PC, but it' still same. It always stacks the same 2 images out of the total of 6.

If I uncheck those 2 imags, it just stacks 1 other out of the 4 remaining.

I can't understand why it would do this on one DSO, yet on another, it stacks all 6 subs!

Please help!

[Parallax]

Have you tried lowering the star detection threshold?

It's in the Advanced tab after you click Register Images.

HTH

Steve

[rikyuu]

Have you tried lowering the star detection threshold?

It's in the Advanced tab after you click Register Images.

HTH

Steve

Thanks Steve, but still no success I'm afraid. I've tried from 10 stars detected to about 10,000 (the max), it stacks 1 to 3 frames respectively, so it has some affect, but something strange is still going on.

I'm stacking RAW images from a 300d, ISO400 so quite low noise. If I convert them to TIFFs, it stacks all 6 subs, but does a poor job and puts them way out of alignment, even though they are already pretty well aligned as they were autoguided.

However, if I halve the image size of the TIFFs, then it works fine and stacks all 6 with a great result.

Any ideas anyone?

[dph1nm]

Has the alignment worked on the missing images? Sounds like it hasn't. It should list an X and Y offset in the image list at the bottom if it has. If aligment has failed, the first thing I do is go to the star editor and check which stars it is actually finding on each image.

NigelM

[rikyuu]

Thanks Nigel, after reading your post, I checked the image list and scrolled across to see the number of stars detected, which I haven't done before (I'm quite new to DSS). Some frames have very few or no stars detected. I'm wondering if my stars are too elongated. That would explain why, if I reduce the image size by half, it works ok as the stars would cover less pixels.

Where is the star editor which you mention?

Cheers

[rikyuu]

ps.

The frames which aren't stacked have no dX and dY values as you mention.

I just gave it a run through with a high star detection setting, so it detected 56, 166, 139, 290, 177, 339 stars on each frame and it only stacked the frames with 166, 290, 339 stars, but strangely not the one with 177 stars (it did the 166 star frame).

[rikyuu]

having taken some more subs of M27 last night with much better autoguiding, I've found that DSS has worked fine and stacked all 9 of the new subs.

Thank you Nigel and Steve for pointing me towards the 'star detection' issue. It seems it had a problem recognising my 'blobs' as stars!:)