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Messages - mmnb

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1
Juan,
Great info. I did notice that the lines in the PCC graphs were somehow un-compelling fits.  Thank you for taking the time to look at the image and articulate this important advice.

2
Too much green in the first one. Nudged G and B curves, just a bit brighter too.

3
Finally have my hyperstar setup working. My stars suffer from some eccentricity, hopefully will be resolved after tuning collimation.  I also had some backlash in my focusing that must've affected things.

Not sure how I did here.  After calibration and PCC, mostly did some very gentle denoising, deconv, stretching and really just bumped saturation curve.  Other images have better hue contrast between the core and arms, but somehow this looks ok to me.  I noticed a bad blue cast after integration, I fixed with LinearFit.  Not sure how that happened (blue was weaker in flats?) so I don't think I lost any color contrast but a little worried since MaximDL's RAW Color images (automatically debayered, balanced) seem to suggest I would see more.

Would love any constructive crit. 500MB linear xsif after drizzle int and PCC:
https://drive.google.com/open?id=1x3L7CZ7NfR-RFOF9XeV58pQB7R8zwcdr

4
General / Overscan newb questions
« on: 2018 October 15 18:11:08 »
I just got a camera (QHY 16200A) with overscan capabilities, wanted to check my understanding to see if I have this right:

Previously I created a master bias according to the Light Vortex tutorials with a camera that did not have overscan.  I should be able to use the overscan capability to do better bias correction for an image.  Because the bias is dependent on the state of the (non-cooled) components in the camera, overscan provides better correction than a master bias frame from an average of a bunch of rapidly acquired bias images.

The bias for a given image is determined by taking the overscan region, averaging columns and fitting a smooth representation of bias *along* the columns.  This is done for *all* images (lights, darks, flats).  The master bias (now the zero frame) is also corrected this way.  The zero frame is still subtracted from darks, flights and flats the way the original master bias would have been.  All of this is done simply by specifying the overscan regions in BatchPreProcessing.

Is that right?  I am not sure what the 'target' region is in the overscan region specification.  Does using the overscan region provide materially better accuracy than simply making a master bias out of a quickly acquired set of bias frames?

5
Here is how I did by the end.  Some problems during acquisition:

-Temp was high (the SBIG 402ME could only get to -10C for most of it)
-Moonlight was bad giving a high background
-Focuser screws came loose, causing a change in camera angle

I just started autofocusing between subs, and my stars look a lot better than previous attempts.

This is the image using just RGB and excluding L.  There is a lot of data in L (19 exposures, 5min each) but no amount curve adjustment etc. would make the central galactic bulge 'fade out' to the background....the change would always be abrupt.  Simply taking the PCC'd rgb image and doing a bit of curve adjustment got a much better result (where the bulge looks more correct).

luminance:
https://drive.google.com/open?id=1CbhL0ghV-jLAIDee-OX_qqd10i2LJo-d

rgb:
https://drive.google.com/open?id=1PcM0M6rkGDY3ZeWrVVM6vsTZ6IVygEOq

If anyone can do much better with the data, I'd love to know how you did it.  I presume the thin profile make it difficult to do a whole lot.

6
I could replicate successfully running ImageSolve first with the parameters in the earlier screenshot and then PCC works (didn't realize that ImageSolve coordinates stick to the image and PCC will use those).

7
(thanks to everyone for looking at this)

Odd. I think I've copied the PCC settings faithfully and I still fail.

8
I should have made the xisf link clearer, apologies.  Didn't realize that the pinpoint routine is robust enough to work in 8-bit depth with the screenshot.

There is no header as the RGB image is the output of several steps, I didn't think the header "carries" as you process. A link to an original raw image (that has coords etc.): https://drive.google.com/open?id=1XBYpe3ocNrPml0H9f2_W9ArZ0MZpTqze

9
Hmmmm, opening the icon and running it on my xisf (I can see the ROI is defined) still fails...
Did a "check for updates" to be sure with no change...time for some sanity checking on my end.

Logging below case anyone else is watching.  Nothing is jumping out at me..






PhotometricColorCalibration: Processing view: Image29
Writing swap files...
383.935 MiB/s

* Using an automatically calculated limit magnitude of 17.

run -x -p="metadata_focal,1371" -p="metadata_xpixsz,9" -p="metadata_ra,189.0866833" -p="metadata_dec,25.9873917" -p="metadata_epoch,2451545" -p="solver_vizierServer,http://cdsarc.u-strasbg.fr/" -p="solver_catalog,Gaia" -p="solver_magnitude,17" -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/dh/gqpnzzg13tg2_t3952x850rr0000gn/T/PCC_T_8MJWEB98G59X.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/dh/gqpnzzg13tg2_t3952x850rr0000gn/T/PCC_T_8MJWEB98G59X.xisf

Reading image:
/var/folders/dh/gqpnzzg13tg2_t3952x850rr0000gn/T/PCC_T_8MJWEB98G59X.xisf
Loading image: w=1530 h=1020 n=3 RGB UInt16
6 FITS keyword(s) extracted.
Seed parameters for plate solving:
   Image coordinates: RA=12 36 20.804, Dec=+25 59 14.61
   Resolution: 1.3540359272238274
Starting StarAlignment iteration
Catalog Gaia already loaded
Catalog Gaia size: 606 objects

Using the triangle similarity algorithm
/var/folders/dh/gqpnzzg13tg2_t3952x850rr0000gn/T/stars.csv:
Scanning star data: done
154 stars.
PCC_T_8MJWEB98G59X:
Structure map: done
Detecting stars: done
75 stars found.
Matching stars: done
10 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #2
useScaleDifferences=true
Matching stars: done
13 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #3
useScaleDifferences=false
* Reference image: Limiting to 125 brightest stars.
Matching stars: done
9 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #4
useScaleDifferences=true
* Reference image: Limiting to 125 brightest stars.
Matching stars: done
11 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #5
useScaleDifferences=false
* Reference image: Limiting to 60 brightest stars.
* Target image: Limiting to 60 brightest stars.
Matching stars: done
10 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #6
useScaleDifferences=true
* Reference image: Limiting to 60 brightest stars.
* Target image: Limiting to 60 brightest stars.
Matching stars: done
12 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #7
useScaleDifferences=false
* Reference image: Limiting to 30 brightest stars.
* Target image: Limiting to 30 brightest stars.
Matching stars: done
12 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #8
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 #9
useScaleDifferences=false
* Reference image: Limiting to 15 brightest stars.
* Target image: Limiting to 15 brightest stars.
Matching stars: done
*** 5 star pair matches found - need at least six matched stars.
* Previous attempt failed - this is try #10
useScaleDifferences=true
* 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 #11
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 #12
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.
*** 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_8MJWEB98G59X.xisf: The image could not be solved

*** Error: Failure to plate solve image: Image29
Reading swap files...
842.929 MiB/s
<* failed *>

10
Mind post a screen shot? It still doesn't solve after resetting (I searched for ngc4565 instead of using the coordinates from a raw image, just to do it the same way)

11
many thanks!

12
Yes, I could not get it to plate solve (perhaps more stupidity in what I am doing than I originally guessed). I'll play around with things a bit more knowing that it should just work (maybe there is a stale setting in there somewhere).

Yes, I think staralign was fine but just trying to do the best I can with this dataset given a lot of things were suboptimal (I think I could only cool to -13C on most exposures on the SBIG 402ME). Taking the wins where one can find them, I am pretty confident about focus now (this was keeping me up at night).

13
Image Processing Challenges / PCC help...again for ngc4565
« on: 2018 June 05 09:15:44 »
Some stupidity and a little bad luck led to the focuser screws coming loose, changing the camera angle midway and giving a funny alignment; as resolved in another thread, moonlight was pretty bad as well (DBE leaves a bit of a dark spot around the galaxy..seems difficult to avoid).  One thing that did go well is that I was able to collect while autofocusing between subs on a nearby star (FWHM for subs seemed significantly improved).

PCC still seems difficult after trying to play with focus length/pixel size (FL: 1371.60, pixel size 9).  Trying to figure out if it is the image quality (FWHM, noise etc.) or the ugly cropped areas that might be interfering with things?

https://drive.google.com/open?id=1BmgayEaRCDwF4dsZuBDhwWgae0FGL2QV

14
Very helpful, that was the explanation I needed!

Many thanks again. Will post results when I am done.

15
That sounds right.  Many thanks!

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