Unable to get ImageSolver to work

[67SS]

Hi all,

I'm having a heck of a time getting my images to plate solve. Some of my longer focal length images (300mm) will solve, but my widefield (24mm) images don't seem to ever work. I've tried downloading all the GAIA files and a myriad of other suggestions I've seen people make, but no luck. I've tried stretching the image first. I've tried BlurXterminator just to tighten things up a bit.

Sometimes ImageSolver kicks off and seems to fail without even trying, even when I've selected the local server. Sometimes it sits there and chews on it for a while and then fails with the same error.

Here are the settings I'm currently trying (I've tried having distortion correction on and off). This is set to Antares I think as the reference star, but I've also tried using M8, and some other random star I determined to be near the center of the frame via Aladin. The camera is a Canon R5, and as best I can tell, the image scale and pixel size are correct (and this particular image was shot at 24mm).

Here's a link to the file (apologies, I tried getting the XISF to upload by my internet is sucking - tif it is!): https://www.dropbox.com/s/8e7kkj59jxqksl2/Milky Way 24mm.tif?dl=0

Here's the error I'm getting

 

[bulrichl]

Your seed coordinates are wrong. Antares is located halfway from the image center to the lower left corner.

I used the coordinates of Omi Ser (RA 17 42 37, DE -12 53 07) as seed coordinates, and applied 'Distortion Correction'. This is the result:

Image Plate Solver script version 5.6.6
===============================================================================
Referentiation matrix (world[ra,dec] = matrix * image[x,y]):
+2.84783761e-03 -1.05083998e-02 +1.70190992e+01
+1.05279954e-02 +2.82893110e-03 -5.08447967e+01
WCS transformation ....... Thin plate spline
Control points ........... 289
Spline lengths ........... l:289 b:289 X:289 Y:289
Projection ............... Gnomonic
Projection origin ........ [4096.021842 2729.616769] px -> [RA: 17 44 01.567 Dec: -12 45 09.58]
Resolution ............... 39.220 arcsec/px
Rotation ................. 105.165 deg
Reference system ......... ICRS
Observation start time ... 2021-09-05 20:25:00 UTC
Focal distance ........... 23.09 mm
Pixel size ............... 4.39 um
Field of view ............ 89d 14' 11.2" x 59d 30' 59.0"
Image center ............. RA: 17 43 57.571 Dec: -12 44 33.28 ex: +0.000011 px ey: -0.000176 px
Image bounds:
top-left .............. RA: 19 07 15.021 Dec: -52 29 25.99 ex: -0.027195 px ey: -0.007334 px
top-right ............. RA: 19 53 05.426 Dec: +16 06 28.92 ex: -0.025677 px ey: +0.008785 px
bottom-left ........... RA: 15 03 52.487 Dec: -36 57 10.29 ex: -0.003310 px ey: -0.013035 px
bottom-right .......... RA: 16 47 11.296 Dec: +27 59 19.56 ex: -0.016517 px ey: +0.003680 px


Bernd

 

[67SS]

I'll be a son of a gun - worked immediately.

Would you mind talking me through how you landed on using Omi Ser as the coordinates?

Thanks for the help!
Dan

 

[fredvanner]

Would you mind talking me through how you landed on using Omi Ser as the coordinates?

I'll leave @bulrichl to answer this, but I would just examine the region in my planetarium program (I use Cartes du Ciel), and estimate what was the brightest star near the centre of the image.

 

[67SS]

I'll leave @bulrichl to answer this, but I would just examine the region in my planetarium program (I use Cartes du Ciel), and estimate what was the brightest star near the centre of the image.

Thank you Fred. So there is, indeed, cause to try to find something significant near the center of the frame, rather than just finding a star that's in the frame *somewhere*.

 

[bulrichl]

I'll leave @bulrichl to answer this, but I would just examine the region in my planetarium program (I use Cartes du Ciel), and estimate what was the brightest star near the centre of the image.

THIS is funny: I just exactly did what Fred wrote: examined the region in my planetarium program (I use Cartes du Ciel) ...

Bernd

 

[bulrichl]

Thank you Fred. So there is, indeed, cause to try to find something significant near the center of the frame, rather than just finding a star that's in the frame *somewhere*.

Whith images of lower field of view, it is usually sufficient when the object that was used for specifying the seed coordinates is located somewhere in the image. However for real widefield images (consider that your image has a field of view of 89.2 x 59.5 degrees!), the object should be located near the image center.

Bernd

 

[67SS]

Thank you gentlemen for your insights here. If I may impose one more time - https://www.dropbox.com/s/yp1c751cp6jcv4j/18mm.tif?dl=0

For this one, I've tried the following stars, Zeta Oph, Eta Oph, Nu Oph, as well as Omi Ser and Antares again (just because I can't help but see it), and can't seem to get a hit. This image is admittedly more noisy, and is a wider view (Nu Oph seems to be the most central star). Would you change your approach to this one? Or do you just keep hunting around until you get a hit?

Thanks again,
Dan

 

[bulrichl]

Seed coordinates (Nu Ser):
RA 17 20 59, DE -12 50 49

This led to the following warning:

** Warning: The image could not be fully solved: Error: SurfaceSpline::Initialize(): At least three input nodes must be specified.
The image has been tagged with the latest known good solution.
* Successful astrometry optimization. Score = 752.16

Saving keywords...
Saving properties...
Saving control points...
Saved 840 control points.

Image Plate Solver script version 5.6.6
===============================================================================
Referentiation matrix (world[ra,dec] = matrix * image[x,y]):
-9.88969729e-03 +9.74835707e-03 +1.38659833e+01
-9.74323651e-03 -9.92199044e-03 +6.69883461e+01
WCS transformation ....... Thin plate spline
Control points ........... 840
Spline lengths ........... l:840 b:840 X:840 Y:840
Projection ............... Gnomonic
Projection origin ........ [4094.146982 2731.115696] px -> [RA: 17 15 33.176 Dec: -11 11 42.20]
Resolution ............... 50.027 arcsec/px
Rotation ................. -44.588 deg
Reference system ......... ICRS
Observation start time ... 2021-09-05 20:25:00 UTC
Focal distance ........... 18.10 mm
Pixel size ............... 4.39 um
Field of view ............ 113d 49' 27.8" x 75d 54' 55.3"
Image center ............. RA: 17 15 19.170 Dec: -11 17 06.63 ex: -0.000033 px ey: -0.000155 px
Image bounds:
top-left .............. RA: 18 01 10.467 Dec: +37 51 42.34 ex: +0.027517 px ey: +0.006297 px
top-right ............. RA: 13 50 57.646 Dec: -15 29 32.20 ex: +0.011838 px ey: -0.000302 px
bottom-left ........... RA: 20 31 25.687 Dec: +0 58 44.52 ex: +0.015169 px ey: +0.019944 px
bottom-right .......... RA: 16 04 45.364 Dec: -59 17 58.03 ex: +0.001043 px ey: +0.014095 px

Seems that this is a borderline case.

Bernd

 

[67SS]

Dang, so I was hitting all around the star that you selected. Would you mind posting your settings for Advanced and Distortion? Are there any settings in there that might help my cause with these very wide field views?

Dan

 

[bulrichl]

Advanced Parameters:
Projection: Gnomonic, Alignment algorithm: Triangle similarity, Detection scales: 5, Minimum structure size: 0, Hot pixel removal: 1, Noise reduction: 0, Sensitivity: 0.50, Peak response 0.50, Bright threshold: 3.00, Maximum distortion: 0.60, PSF search radius: 12, option 'Optimize solution' enabled

Distortion Correction (enabled):
Spline smoothing: 0.015, option 'Use surface simplifiers' enabled, Simplifier tolerance: 0.05, Simplifier rejection: 0.10

As far as I know these settings result when the script is reset to default values.

Bernd

 

[67SS]

Yep, as best I can tell, you're correct.

So with these wide images, I'm going to just have to hunt and peck around until I find the right star? No other way around it?

Dan

 

[bulrichl]

You can crop the image in PixInsight (symmetrically regarding top/bottom and left/right margins), save the result as file in JPG or PNG format and upload it to astrometry.net (supported formats: JPEG, GIF, PNG or FITS) in order to platesolve and find out the center coordinates of the image. I guess the approach using a planetarium software is just as fast.

Bernd

 

[67SS]

Thanks for the help! I think I've found a way to do this, using your guidance. Using the DBE tool for it's crosshairs, I zoomed in to see what was just around dead center, and then using the planetarium software was able to locate the star, and get a proper solution to a different image than the ones I've shared. I feel successful!

Thanks again!
Dan

 

[stardad1994]

I need help as well. I have provided a link to my TIF file:

Dropbox - File Deleted - Simplify your life

www.dropbox.com

I have centered using astrometry.net and by looking at the closest star in Stellarium. I suspect another issue besides centering as the focal length is 360 mm and not 24 mm as above ...but I get the same error message. I have performed every permutation I can think of in Plate Solver but I have been unsuccessful. I have spent 1.5 full days on this issue.

Any advice is appreciated to get this to Plate Solve in PI as I would like to perform SPCC.

Thanks!
Marc

 

[cloudbait]

I need help as well. I have provided a link to my TIF file:

Dropbox - File Deleted - Simplify your life

www.dropbox.com

I have centered using astrometry.net and by looking at the closest star in Stellarium. I suspect another issue besides centering as the focal length is 360 mm and not 24 mm as above ...but I get the same error message. I have performed every permutation I can think of in Plate Solver but I have been unsuccessful. I have spent 1.5 full days on this issue.

Any advice is appreciated to get this to Plate Solve in PI as I would like to perform SPCC.

Thanks!
Marc

While a 24-bit color TIFF is far from ideal for anything you want to do, I didn't have any problem running it through ImageSolver. I don't know your pixel size, so the calculated focal length is meaningless, but that doesn't impact the solving process. A proper astronomical image file would contain a header with the approximate image center and the pixel scale. I got those from astrometry.net. Plugged in to ImageSolver that script did its thing with no adjustments from the default settings.

 

[fredvanner]

I have provided a link to my TIF file:

This image solved immediately for me with intial seed:
Center coordinates: RA = 11 18 55.908, Dec = +13 05 32.30
Resolution: 2.600 as/px
(using M65 search for start position,and a manually estimated resolution).

 

[stardad1994]

Any thoughts WTH I am doing wrong? I solved in Astrometry as well. Is there a way to take the coordinates from astrometry.net and plug them into PI? I also tried using M65 as a start position but error again....).

Where did you get this table from in PI?

Thanks.

Marc

 

[pfile]

you can just manually plug in the coordinates from Astrometry.net into the ImageSolver interface.

that table is what you get on the PI console after a successful solve.

rob

 

[cloudbait]

Any thoughts WTH I am doing wrong? I solved in Astrometry as well. Is there a way to take the coordinates from astrometry.net and plug them into PI? I also tried using M65 as a start position but error again....).

Where did you get this table from in PI?

I just manually typed in the coordinates and the pixel scale from astrometry.net. The table is just a screen shot from the process console window after the solve.