Another question about streaks in images

AstroSharp Ltd SharpCap Celestron EdgeHD 8" Acquisition Deep Sky Artifacts
4 replies•100 views
Keith R. avatar
Keith R. avatar
Hello.  I see a lot of posts asking "What causes this?" but none seem to be exactly what I am experiencing.
The following image is a simple stretch on my master light stack before any post-processing.  This was stacked in PI using WBPP script.  I have lights, darks, darkflats, flats, and a master bias.  I believe all of the settings were at or close to default.
This was taken through an EDGEHD 8" with an ASI294MC Pro using SharpCap 4.1.
I don't understand where the diagonal streaks are coming from.  I went out 4 other nights to image the same galaxy and there are no streaks in those stacks.
I am really curious to see if anyone has seen this before and can offer an explanation.
Thank you

Well Written Engaging
Tom Boyd avatar
Tom Boyd avatar
First impression is it looks like walking noise. Are you dithering?
Tony Gondola avatar
Tony Gondola avatar
+1 for walking noise.
andrea tasselli avatar
andrea tasselli avatar
Usually this happens either because you have not dithered or you haven't corrected for noise (CosmeticCorrection).
Keith R. avatar
Keith R. avatar
Thank you for your responses.  I had forgotten about walking noise.
I did a quick stack of the raw frames with no alignment or anything and the stars streaked in the same direction as the stacked image bands, so I did have a bit of field drift.
I have been having problems getting great polar alignment using SharpCap's PA tool.  One cause of that could be flexure, which could also cause the walking noise.  So I'm off to find out where it can be and start saving up for a new OAG and guide camera.  smile

To answer questions - No, I was not dithering.  Looks like I will need to add that to my sequence once I figure out my drift issues…

Thanks again.
Respectful Supportive
Related discussions
Dark vertical streaks in stacked image
I've been struggling with trying to understand the source of these streaks I see in some recent stacked images. I'm hoping someone here can offer an idea as to what the source is. I'm hoping it's not the camera itself. My set up is a ...
Diagonal streaks in stacked images similar to your reported issue.
Aug 21, 2025
WBPP interactive frame selection: tracking included frames for Astrobin uploads
I used the new interactive mode for frame selection in WBPP and it works great. It is easy to see what should be rejected in your light frames and what to include. It saves the hassle of getting into SubFrameSelector and making a copy of the selected...
WBPP frame selection and processing workflow directly relevant to your setup.
Feb 1, 2026
Flats adding to images instead of subtracting in PixInsight WBPP
Astro Friends, I have been imaging for about 5 years and have been successful using refractors and mono imaging. I have branched out this year and now have an SCT and mono setup. I am seeking help with my flats which seem to add themselves to my imag...
Flat calibration issues in WBPP that could cause stacking artifacts.
Jan 2, 2026
Green banding issue in WBPP when using flats
Does anyone know what might be causing this green banding? I’ve never encountered this issue before, and it disappears when I exclude flats from WBPP. I have inspected my flats, and they seem normal. I’ve yet to try retaking the flats or do more test...
WBPP processing artifacts that may relate to your diagonal streak problem.
Feb 7, 2026
Strange light at all OIII antlia 3nm filter
Hi everybody, Id like to ask here about strange behavior of my Pelican Nebula imaging. Last night Ive get on all of my OIII images this strange scattered (?) light. Could anyone tell me, what it can be? thank you and CS!
Explores causes of streaks and artifacts appearing in astrophotography images.
Apr 23, 2023