PI1.8-1054: ImageSolver script fails with "TypeError: p is null"

[georg.viehoever]

Console output:

Code: [Select]

run --execute-mode=auto "C:/Program Files/PixInsight/src/scripts/AdP/ImageSolver.js"

Processing script file: C:/Program Files/PixInsight/src/scripts/AdP/ImageSolver.js

Searching in Sesame:
http://cdsweb.u-strasbg.fr/cgi-bin/nph-sesame/-oI/A?orion
820 bytes transferred in 0.78 s @ 1.03 KB/s
Seed parameters for the plate solving:
   Image coordinates: RA=05 35 17.300, Dec=-05 23 28.00
   Resolution: 96.25690794273292
Starting StarAlignment iteration

Downloading Vizier data:
http://vizier.u-strasbg.fr/viz-bin/asu-tsv?-source=V/50/catalog&-c=83.822083 -5.391111&-c.r=104.492221&-c.u=deg&-out.form=|&-out.add=_RAJ,_DEJ&-out=pmRA&-out=pmDE&-out=Name&-out=HR&-out=HD&-out=DM&-out=SAO&-out=Vmag&-out=B-V&-out=U-B&-out=R-I&-out=SpType&Vmag=<11
602836 bytes transferred in 1.04 s @ 563.36 KB/s
Using epoch: 2013.1690622861054
Catalog Bright Stars  size: 5674 objects
*** Error [222]: C:/Program Files/PixInsight/src/scripts/AdP/WCSmetadata.jsh, line 899: TypeError: p is null


[Andres.Pozo]

Hi Georg,

could you upload anywhere the image that fails?

Andrés.

[georg.viehoever]

Hi Andres,
Settings as shown in attached screenshot (Center M42, focal length 12 mm, pixel size 5.6 um). The Image is available on https://skydrive.live.com/?cid=c56e60845cfa6790&id=C56E60845CFA6790%21247&sff=1#cid=C56E60845CFA6790&id=C56E60845CFA6790%21247&v=3.
Georg

[Andres.Pozo]

Hi Georg,

there is a bug in the script for images of very short focal length. I have fixed it and I have sent it to Juan. The new version have also a few additional improvements. However, I don't think you are going to be able to solve that image without a very good distortion model.

[georg.viehoever]

Thanks for looking into it. I will give it another try (with distortion model) when the new version is released.
Georg

[Andres.Pozo]

Thanks for looking into it. I will give it another try (with distortion model) when the new version is released.
Georg

You can use ManualImageSolver for generating the distortion model:
http://pixinsight.com/forum/index.php?topic=5817.0
http://pixinsight.com/forum/index.php?topic=5657.0

The funny thing is that if you solve the image with ManualImageSolver, then you don't need the model for ImageSolver 
In any case, you can keep the model for solving other images taken with the same optical configuration.

[georg.viehoever]

Hi Andres,
I tried the version of the script that you published in http://pixinsight.com/forum/index.php?topic=6535.0 . It solves with a residual of ~3 pixels, but when I use it to annotate, I get the result shown in the attachment: Orion clearly has an offset of more than 3 pixels....
Georg

[Andres.Pozo]

Hi Andres,
I tried the version of the script that you published in http://pixinsight.com/forum/index.php?topic=6535.0 . It solves with a residual of ~3 pixels, but when I use it to annotate, I get the result shown in the attachment: Orion clearly has an offset of more than 3 pixels....
Georg

Before using a solution you have to check if it is valid.  In this case your image is clearly not well solved. You should try to set a better starting point, find a good value for the sensitivity and select the catalog Bright Stars.

However, I don't know if you are going to be able to get a good solution for that image. It seems to be taken with a quite short focal length and it probably requires a distortion model. It also has very few stars, so it has very few information to work with. Perhaps ManualImageSolver could find a workable solution.

ImageSolver currently does not validate the solution. I am thinking in implementing an automatic validation that warned if the solution was suspicious, but it is not easy.

[georg.viehoever]

Hi Andres,

I did use the bright star catalog.  The output saod that it solved with 3 pixels error for 340 stars, see below. The distortion map looked reasonable (see screenshot), so I felt that teh result was reasonable. However, looking at the star map (screenshot right) suggests that the matching happened to noise artifacts  .

Hmm.
Georg

Code: [Select]

DynamicPSF: Global context
1 view(s)
1308 star(s)
796 PSF fittings
5.205 s
Error StdDev=9.74 pixels
Tolerance for rejecting stars: 5.00 pixels
Valid stars: 347
Rejected stars: 449

*****
Iteration 9, delta = 3.735 arcsec (0.04 pixels)
Image center ...... RA: 04 58 36.163  Dec: +09 02 04.88
Resolution ........ 99.02 arcsec/pix
RMS ............... 2.9334 pix (347 stars)
*****
Calculating final referentiation matrix
Creating distortion map
Creating error map

Image Plate Solver script version 3.4
===============================================================================
Referentiation Matrix (Gnomonic projection = Matrix * Coords[x,y]):
             -0.0245597          -0.0135946            +65.7007
             +0.0127134          -0.0237502            +6.00265
                     +0                  +0                  +1
Projection origin.. [1954.438883 1299.232663]pix -> [RA:+04 58 36.16 Dec:+09 02 04.88]
Polynomial degree.. 3
Resolution ........ 99.020 arcsec/pix
Rotation .......... 28.867 deg
Focal ............. 11.67 mm
Pixel size ........ 5.60 um
Field of view ..... 107d 29' 30.4" x 71d 34' 10.2"
Image center ...... RA: 04 58 32.972  Dec: +08 59 13.27
Image bounds:
   top-left ....... RA: 08 17 57.292  Dec: +09 44 10.82
   top-right ...... RA: 02 49 56.149  Dec: +48 28 36.93
   bottom-left .... RA: 06 38 08.401  Dec: -32 33 12.92
   bottom-right ... RA: 01 43 41.199  Dec: +01 59 08.61
===============================================================================


[georg.viehoever]

A question: Is the Errors-Plot for stars that were actually matched, or is it for all detected stars based on the destortion model found? When I compare the found stars (ticked at sensitivity slider) to those on the error plot, I just cannot match them properly.
Georg