Help - what are these artefacts???

[AMcD]

Has anyone seen X shaped artefacts like this before?  They seem to appear when I shoot to the West.  I have covered up a chrome smoke stack that I thought might be causing reflections but this roughly processed data was gathered subsequently.  If anyone has any suggestions I would be very grateful.  It has ruined hours of data.

[Seelive]

What are you using to stack the data? I've once seen similar artifacts from one of my DSS stacks, changing the alignment method (from the default automatic) removed them.

[david_taurus83]

Are they on every sub?

[AMcD]

30 minutes ago, david_taurus83 said:

Are they on every sub?

Good point.  No, they are not on every sub, and, as far as I can see, not on any of the subs.  Does this suggest, as Seelive points out, that they are perhaps a processing artefact from DSS?

[AMcD]

3 hours ago, david_taurus83 said:

Are they on every sub?

 

4 hours ago, Seelive said:

What are you using to stack the data? I've once seen similar artifacts from one of my DSS stacks, changing the alignment method (from the default automatic) removed them.

I have now traced the artefacts to the dark frames.  I am not sure why the dark frames have these artefacts but it is reassuring to know the luminance data is sound!  Many thanks to you both for your help.🙂

[AMcD]

9 hours ago, AMcD said:

 

I have now traced the artefacts to the dark frames.  I am not sure why the dark frames have these artefacts but it is reassuring to know the luminance data is sound!  Many thanks to you both for your help.🙂

Just as a quick follow up, I took the dark frames the morning after I had finished imaging, i.e. when it was light.  I suspect therefore that there is a light leak, which led to the artefacts on the dark frames.   There is an old thread from CN from 2008 that speaks about this issue which reinforces my conclusions in this regard. 

[Seelive]

6 hours ago, AMcD said:

Just as a quick follow up, I took the dark frames the morning after I had finished imaging, i.e. when it was light.  I suspect therefore that there is a light leak, which led to the artefacts on the dark frames.   There is an old thread from CN from 2008 that speaks about this issue which reinforces my conclusions in this regard. 

Pleased to hear you've found a probable cause - sometimes calibration frames can cause more problems than they solve 😕