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Messages - GordonH

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Registration was done after debater. The initial processing was done with the BatchPreprocessing. Additional integration attempts were done with the debayered-aligned images. (For clarification, the attached image was the extracted luminance channel.)


I imaged NC925 and while processing I noticed a "checker board pattern" in the background and persists into the higher signal area of the galaxy itself. The pattern runs at an angle to the row/columns of the sensor pixels. I've attached a grossly overstretched image to illustrate the conditions.

The images were taken with a Canon 6D DSLR using an AstroTech AT10RC scope. Acquisition software is TheSkyX Camera Add-in.  I've been using this combo for about the last 9 months and have not seen the pattern previously. I did go back and check some previous images.

I initially used 38 - 8 minute subs (I image from pretty badly light polluted skies and needs lots of subs!) I dithered these subs with an off-set of 10 pixels on the guide camera (translates to about 26 pixels on the image.) After seeing the pattern I inspected the individual subs, the master bias, dark, and flat and could not discern the pattern. I then stacked groups of 10 subs from the beginning and end of the run. The pattern appeared. I initially stacked using LinearFit, but, also tried WinsorizedSigma.

My next thought was some kind of relationship to the dithering pattern (TheSkyX seems to move the same number of pixels between each sub??) I re-imaged the target about 3 weeks later (I live in Michigan - you don't get many clear nights!) this time with the dither set to 5 pixels. Same result. I then stacked all the images together, tried the different rejection techniques and then started over with all the frames and used the Bayer drizzle routine in BatchPreprocessing. That's what was used for the attached image.

I also separated and inspected  the R - G - B channels from the integrated image. The pattern appear in all three channels, but, more noticeable in the red.

If the pattern were aligned with the sensor I would blame the camera. The fact that its on an angle leaves me puzzled.

Any ideas / help will be appreciated.


Bug Reports / Re: Images Saved with STF are Permanently Altered
« on: 2016 February 12 18:15:04 »
Thanks all for the responses. Another lesson learned!

I did do some more "experimenting." If I reopen a file saved with an STF stretch after restarting PixInsight, it will not re-set by clicking the reset button. You must first click on the AutoStretch button. then the Reset works.

Once again thanks for the help.


Bug Reports / Images Saved with STF are Permanently Altered
« on: 2016 February 11 12:45:07 »
My normal routine is to use STF to examine an image right after ImageIntegration and then save this image. In the past these images would reopen without any stretching. That no longer appears to be true.

If I save the image, close it down, and then reopen, it immediately appears stretched. Resetting in the STF will return it to its unstretched state. However, if I shut PixInsight down and then restart and open the image, it again appears stretched, but, that stretch is now permanent.

Not sure when this started. I recently upgraded to Windows 10 and the the same behavior occurs on both my desktop and laptop computers.

Gordon Hansen

General / Re: Comet Alignment Problem
« on: 2013 November 13 13:25:30 »
I had the same issue with version 1.8. I capture images using CCDSoft and it writes the DATE-OBS entry with decimal seconds (nnn.ddd) I manually edited the entries leaving only whole seconds. That corrected the problem. Now to figure out how to make CCDSoft leave of the decimals in the first place!


Bug Reports / Re: Corrupted shared image structure errors
« on: 2013 February 11 13:35:27 »
I get the error every time I close an image that's been operated on. I've reopened them and there doesn't seem to be any issues.

Gordon Hansen

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