Trouble with star alignment in livestacking
Posted: Thu Apr 29, 2021 4:44 pm
Failure due to lack of stars to align has been discussed several times in this forum - it continues to be the one area where I find it difficult to get SC to work reliably.
I have so far tried all the suggested methods - reset, reduce black threshold, histogram adjustments, digital gain, etc etc. I got it working for one set of data by setting the dark and flats. Adding background subtraction caused it to fail again.
The settings that worked for one dataset did not for another.
When the stack is run through a stacking program, it finds several stars to align on.
For one image that showed 0 stars, the log is reproduced below. the image, saved as Exactly as seen, is also enclosed. ASTAP solves it in 0.3 sec, so the stars are there. It had darks and flats, no background subtraction.
I am enclosing the screenshot version as the file size is more than the limit allowed. But even in this, the number of stars visible is much more than 3.
Any suggestions?
21:54:06 INFO Detected 0 in the stacked image, mean FWHM is NaN
21:54:06 INFO Detected 0 stars in the frame image, mean FWHM is NaN
21:54:06 ERROR Less than 3 stars found in the frame image
21:54:06 ERROR Alignment failed
21:54:06 ERROR System.InvalidOperationException: Less than 3 stars found in the frame image - cannot align.
at SharpCap.ImageProcessing.Aligner.CheckFrameStars() in C:\Documents\Source Code\SharpCap\src\SharpCap.ImageProcessing\Aligner.cs:line 251
at SharpCap.ImageProcessing.Aligner.GetFrameTriangles() in C:\Documents\Source Code\SharpCap\src\SharpCap.ImageProcessing\Aligner.cs:line 240
at SharpCap.ImageProcessing.Aligner.GetAlignmentMatrix(Boolean lockToScaleOne, Int32 width, Int32 height) in C:\Documents\Source Code\SharpCap\src\SharpCap.ImageProcessing\Aligner.cs:line 129
at SharpCap.ImageProcessing.Aligner.GetAlignmentMatrix(ICapturedFrame frame, Boolean lockToScaleOne) in C:\Documents\Source Code\SharpCap\src\SharpCap.ImageProcessing\Aligner.cs:line 114
at SharpCap.FrameTransforms.LiveStacking.LiveStackProcessor.CalculateAlignment(ICapturedFrame frame) in C:\Documents\Source Code\SharpCap\src\SharpCap\FrameTransforms\LiveStacking\LiveStackProcessor.cs:line 493
21:54:06 ERROR Failed to calculate alignment.
21:54:06 WARN Frame not stacked because : Could not align
I have so far tried all the suggested methods - reset, reduce black threshold, histogram adjustments, digital gain, etc etc. I got it working for one set of data by setting the dark and flats. Adding background subtraction caused it to fail again.
The settings that worked for one dataset did not for another.
When the stack is run through a stacking program, it finds several stars to align on.
For one image that showed 0 stars, the log is reproduced below. the image, saved as Exactly as seen, is also enclosed. ASTAP solves it in 0.3 sec, so the stars are there. It had darks and flats, no background subtraction.
I am enclosing the screenshot version as the file size is more than the limit allowed. But even in this, the number of stars visible is much more than 3.
Any suggestions?
21:54:06 INFO Detected 0 in the stacked image, mean FWHM is NaN
21:54:06 INFO Detected 0 stars in the frame image, mean FWHM is NaN
21:54:06 ERROR Less than 3 stars found in the frame image
21:54:06 ERROR Alignment failed
21:54:06 ERROR System.InvalidOperationException: Less than 3 stars found in the frame image - cannot align.
at SharpCap.ImageProcessing.Aligner.CheckFrameStars() in C:\Documents\Source Code\SharpCap\src\SharpCap.ImageProcessing\Aligner.cs:line 251
at SharpCap.ImageProcessing.Aligner.GetFrameTriangles() in C:\Documents\Source Code\SharpCap\src\SharpCap.ImageProcessing\Aligner.cs:line 240
at SharpCap.ImageProcessing.Aligner.GetAlignmentMatrix(Boolean lockToScaleOne, Int32 width, Int32 height) in C:\Documents\Source Code\SharpCap\src\SharpCap.ImageProcessing\Aligner.cs:line 129
at SharpCap.ImageProcessing.Aligner.GetAlignmentMatrix(ICapturedFrame frame, Boolean lockToScaleOne) in C:\Documents\Source Code\SharpCap\src\SharpCap.ImageProcessing\Aligner.cs:line 114
at SharpCap.FrameTransforms.LiveStacking.LiveStackProcessor.CalculateAlignment(ICapturedFrame frame) in C:\Documents\Source Code\SharpCap\src\SharpCap\FrameTransforms\LiveStacking\LiveStackProcessor.cs:line 493
21:54:06 ERROR Failed to calculate alignment.
21:54:06 WARN Frame not stacked because : Could not align