Photometric Color Calibration Problems after stacking

[alanrock]

Photometric Color Calibration seems to work fine when I use it on my subs, but fails every time when I try to use it after stacking. Am I missing something?
Thanks!

[RickS]

Is it the plate solving that fails?  I plate solve my original registration reference sub with ImageSolver and then use the "Acquire from Image" button on PCC rather than try to solve the combined image.

[alanrock]

Yes, it's the plate solve that's failing, even though I am also using the "acquire from image" option.

[RickS]

That's very odd.  What's the error message?  Have you cropped or otherwise transformed the RGB so it doesn't match the reference sub?

[alanrock]

I haven't made any changes to the file. Here's some of the log file:
*** 0 star pair matches found - need at least six matched stars.
* Previous attempt failed - this is try #14
useScaleDifferences=true
* Reference image: Limiting to 8 brightest stars.
* Target image: Limiting to 8 brightest stars.
Matching stars: done
*** 0 star pair matches found - need at least six matched stars.
* Previous attempt failed - this is try #15
useScaleDifferences=false
* Reference image: Limiting to 500 brightest stars.
* Target image: Limiting to 500 brightest stars.
Matching stars: done
91 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #16
useScaleDifferences=true
* Reference image: Limiting to 500 brightest stars.
* Target image: Limiting to 500 brightest stars.
Matching stars: done
128 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #17
useScaleDifferences=false
* Target image: Limiting to 1000 brightest stars.
Matching stars: done
135 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #18
useScaleDifferences=true
* Target image: Limiting to 1000 brightest stars.
Matching stars: done
162 putative star pair matches.
Performing RANSAC: done
*** Error: Unable to find an initial set of putative star pair matches
*** Error: The image could not be aligned with the reference star field
Please check the following items:
The initial coordinates should be inside the image.
The initial resolution should be within a factor of 2 from the correct value.
Adjust the star detection sensitivity parameter, so that the script can detect most of the stars in the image without mistaking noise for stars.
The catalog should be matched to the image. Choose the appropriate catalog and magnitude filter, so that the number of stars extracted from the catalog can be similar to the number of stars detected in the image.
*** The image could not be solved.
This is usually because the initial parameters are too far from the real metadata of the image.

** Warning: Process finished with errors:
  PCC_T_UWW72U5HLTZ2.xisf: The image could not be solved

*** Error: Failure to plate solve image: light_BINNING_1_integration1
Reading swap files...
761.982 MiB/s
<* failed *>

PhotometricColorCalibration: Processing view: light_BINNING_1_integration1
Writing swap files...
511.378 MiB/s

* Using an automatically calculated limit magnitude of 12.

run -x -p="metadata_focal,540" -p="metadata_xpixsz,9" -p="metadata_ra,0.9946708333333332" -p="metadata_dec,67.22190833333333" -p="metadata_epoch,2451545" -p="solver_vizierServer,http://cdsarc.u-strasbg.fr/" -p="solver_catalog,TYCHO-2" -p="solver_magnitude,12" -p="solver_sensitivity,-1" -p="solver_noiseLayers,0" -p="solver_alignAlgorithm,0" -p="solver_distortionCorrection,false" -p="solver_splineSmoothing,0.05" -p="solver_projection,0" -p="solver_catalogMode,1" -p="solver_autoMagnitude,false" -p="solver_showStars,false" -p="solver_showDistortion,false" -p="solver_generateErrorImg,false" -p="solver_generateDistortModel,false" -p="solver_useDistortionModel,false" -p="solver_onlyOptimize,false" -p="solver_outSuffix," -p="solver_projectionOriginMode,0" -p="solver_useActive,false" -p="solver_files,/var/folders/ww/b9td77354zgg_vd3bp3qvz_h0000gn/T/PCC_T_G8X8SM6DYB4N.xisf" -p="non_interactive,true" -p="isGlobalTarget,true" -p="isViewTarget,false" "/Applications/PixInsight/src/scripts/AdP/ImageSolver.js"

Processing script file: /Applications/PixInsight/src/scripts/AdP/ImageSolver.js

*******************************
Processing image /var/folders/ww/b9td77354zgg_vd3bp3qvz_h0000gn/T/PCC_T_G8X8SM6DYB4N.xisf

Reading image:
/var/folders/ww/b9td77354zgg_vd3bp3qvz_h0000gn/T/PCC_T_G8X8SM6DYB4N.xisf
Loading image: w=5496 h=3672 n=3 RGB UInt16
203 FITS keyword(s) extracted.
Seed parameters for plate solving:
   Image coordinates: RA=00 03 58.721, Dec=+67 13 18.87
   Resolution: 3.437746770784939
Starting StarAlignment iteration

Downloading Vizier data:
http://cdsarc.u-strasbg.fr/viz-bin/asu-tsv?-source=I/259/tyc2&-c=0.994671 67.221908&-c.r=6.297952&-c.u=deg&-out.form=|&-out.max=200000&-out=TYC1&-out=TYC2&-out=TYC3&-out=RAmdeg&-out=DEmdeg&-out=pmRA&-out=pmDE&-out=VTmag&-out=BTmag&-out=HIP&VTmag=<12
582507 bytes transferred in 4.61 s @ 123.32 KiB/s
fov:6.297952 actual:6.297934
Catalog TYCHO-2 size: 7923 objects

Using the triangle similarity algorithm
/var/folders/ww/b9td77354zgg_vd3bp3qvz_h0000gn/T/stars.csv:
Scanning star data: done
1395 stars.
PCC_T_G8X8SM6DYB4N:
Structure map: done
Detecting stars: done
3249 stars found.
* Target image: Limiting to 2000 brightest stars.
Matching stars: done
226 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #2
useScaleDifferences=true
* Target image: Limiting to 2000 brightest stars.
Matching stars: done
320 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #3
useScaleDifferences=false
* Reference image: Limiting to 250 brightest stars.
* Target image: Limiting to 250 brightest stars.
Matching stars: done
52 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #4
useScaleDifferences=true
* Reference image: Limiting to 250 brightest stars.
* Target image: Limiting to 250 brightest stars.
Matching stars: done
76 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #5
useScaleDifferences=false
* Reference image: Limiting to 125 brightest stars.
* Target image: Limiting to 125 brightest stars.
Matching stars: done
39 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #6
useScaleDifferences=true
* Reference image: Limiting to 125 brightest stars.
* Target image: Limiting to 125 brightest stars.
Matching stars: done
42 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #7
useScaleDifferences=false
* Reference image: Limiting to 60 brightest stars.
* Target image: Limiting to 60 brightest stars.
Matching stars: done
23 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #8
useScaleDifferences=true
* Reference image: Limiting to 60 brightest stars.
* Target image: Limiting to 60 brightest stars.
Matching stars: done
13 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #9
useScaleDifferences=false
* Reference image: Limiting to 30 brightest stars.
* Target image: Limiting to 30 brightest stars.
Matching stars: done
15 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #10
useScaleDifferences=true
* Reference image: Limiting to 30 brightest stars.
* Target image: Limiting to 30 brightest stars.
Matching stars: done
9 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #11
useScaleDifferences=false
* Reference image: Limiting to 15 brightest stars.
* Target image: Limiting to 15 brightest stars.
Matching stars: done
*** 3 star pair matches found - need at least six matched stars.
* Previous attempt failed - this is try #12
useScaleDifferences=true
* Reference image: Limiting to 15 brightest stars.
* Target image: Limiting to 15 brightest stars.
Matching stars: done
*** 0 star pair matches found - need at least six matched stars.
* Previous attempt failed - this is try #13
useScaleDifferences=false
* Reference image: Limiting to 8 brightest stars.
* Target image: Limiting to 8 brightest stars.
Matching stars: done
*** 0 star pair matches found - need at least six matched stars.
* Previous attempt failed - this is try #14
useScaleDifferences=true
* Reference image: Limiting to 8 brightest stars.
* Target image: Limiting to 8 brightest stars.
Matching stars: done
*** 0 star pair matches found - need at least six matched stars.
* Previous attempt failed - this is try #15
useScaleDifferences=false
* Reference image: Limiting to 500 brightest stars.
* Target image: Limiting to 500 brightest stars.
Matching stars: done
86 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #16
useScaleDifferences=true
* Reference image: Limiting to 500 brightest stars.
* Target image: Limiting to 500 brightest stars.
Matching stars: done
120 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #17
useScaleDifferences=false
* Reference image: Limiting to 1000 brightest stars.
* Target image: Limiting to 1000 brightest stars.
Matching stars: done
147 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #18
useScaleDifferences=true
* Reference image: Limiting to 1000 brightest stars.
* Target image: Limiting to 1000 brightest stars.
Matching stars: done
227 putative star pair matches.
Performing RANSAC: done
*** Error: Unable to find an initial set of putative star pair matches
*** Error: The image could not be aligned with the reference star field
Please check the following items:
The initial coordinates should be inside the image.
The initial resolution should be within a factor of 2 from the correct value.
Adjust the star detection sensitivity parameter, so that the script can detect most of the stars in the image without mistaking noise for stars.
The catalog should be matched to the image. Choose the appropriate catalog and magnitude filter, so that the number of stars extracted from the catalog can be similar to the number of stars detected in the image.
*** The image could not be solved.
This is usually because the initial parameters are too far from the real metadata of the image.

** Warning: Process finished with errors:
  PCC_T_G8X8SM6DYB4N.xisf: The image could not be solved

*** Error: Failure to plate solve image: light_BINNING_1_integration1
Reading swap files...

[Scooot]

Hi Alan,
I had a similar problem and fixed it by uploading the image to astrometry.net to check the coordinates etc. http://nova.astrometry.net/upload
Also checking the pixel size.

I saved the file as a duplicated stretched png first. If it still doesnt work I can usually get it to complete by increasing the log sensitivity in the plate solving parameters.

[stevek]

I have absolutely the same problem.
Used to work perfectly.  Now constantly get these errors.

[John_Gill]

Hi,

I always select "Force plate solving" and "Ignore existing metadata"  and you can try and set "Log(sensitivity) to -2.0"  Sometimes if the plate-solving does not go well, then under "Database server" I select a different site.

Look up
John

[Andres.Pozo]

I can help with the ImageSolver script, but I would need the image with problems.

[alanrock]

I chose  "Force plate solving" and "Ignore existing metadata"  and set "Log(sensitivity) to -2.0", and this worked on some of my images. Is there a type of image where this should NOT be used? For example, I used it on a globular cluster with lots of other stars in the field, and the result I got back was not pretty.
Thanks again!

[monkeybird747]

I recently had this happen. In my case the previous target coordinates were still being used even though I was selecting "get coordinates". I had not changed the target in the search box at the top of the get coordinates window. Once searched for new target the proper coordinates popped up and it worked fine.

Also be sure to check the pixel scale and focal length settings. If you drizzle at a scale of 2 you have to double the focal length or half the pixel size (I think I did both and it still worked). From the support documentation:

If you are using drizzle, please remember to change the focal length or the pixel size according to the Scale parameter value used in DrizzleIntegration. For instance, if using a Scale value of 2, you should then multiply the focal length by 2 or divide the pixel size by 2.

[stevek]

I recently had this happen. In my case the previous target coordinates were still being used even though I was selecting "get coordinates". I had not changed the target in the search box at the top of the get coordinates window. Once searched for new target the proper coordinates popped up and it worked fine.

Also be sure to check the pixel scale and focal length settings. If you drizzle at a scale of 2 you have to double the focal length or half the pixel size (I think I did both and it still worked). From the support documentation:

If you are using drizzle, please remember to change the focal length or the pixel size according to the Scale parameter value used in DrizzleIntegration. For instance, if using a Scale value of 2, you should then multiply the focal length by 2 or divide the pixel size by 2.

Thankyou for this.  I had to divide by pixel size by two since I had been using drizzle with scaling of 2 (the default).  This fixed it for me.  Many thanks!