New PixInsight Tutorial: Pre-processing (Calibrating & Stacking) your Images

[Gib007]

Read here: http://lightvortexastronomy.blogspot.com/2015/07/tutorial-pixinsight-pre-processing.html

I have finally been able to finish my pre-processing tutorial for PixInsight. This tutorial covers EVERYTHING from start to finish of how to take your raw exposures (bias, darks, flats and lights), produce masters and use them to calibrate your lights, followed by stacking them including using the Drizzle algorithm to remove pixelation in the final result. The fully manual method is covered in detail. The tutorial also covers use of the BatchPreprocessing script for anyone interested in it. Additionally, there is a discussion of what to do with multiple sets of data for the same object captured over various nights. Enjoy! 

[sloz1664]

Just downloaded and browsed through the tutorial. Superb, just what I needed. I never felt confident in calibrating my images, always used MaximDL.

Now I will certainly use this tutorial to re-process my later images.

Steve

[Gib007]

That's great to hear, Steve! I hope you find the tutorial thorough - I took every measure to make sure it covered everything without exception. 

[Gib007]

I have updated the screenshots on all my current tutorials, including this one, to display them at full-resolution as captured. It should be much easier to read settings on them now.

[joecoyle]

Hi Kayron, 

What can I say? Absolutely fantastic tutorials. For the beginner, I thought calibrating images would be way over my head in PixInsight, but your tutorial has made it so simple (!).

Just need some clear nights to actually image now!

Thanks again for such great tutorials!

Joe

[Gib007]

Thank you Joe!

I have just finished a big update on the tutorial The changes are as follows:

Practically re-wrote sections 4 and 5 in order to re-arrange how the PixInsight pre-processing workflow is applied. Calibrating light frames is now recommended prior to cosmetic correction. Added note about how master dark subtraction from flat frames during the calibration of flat frames can sometimes result in a PixInsight warning about no correlation. Made amendments throughout the text and on various screenshots to properly reflect the changes made. 

[gnomus]

Firstly, let me say thank you very much for this tutorial.  As someone who is just starting out with CCD imaging, it has proven to be extremely helpful.  I followed your tutorial for my first CCD image and was certainly pleased with the Luminance image that resulted.  I also ended up with a much better understanding of how and why the various dark, bias, flat and light frames should be combined.  I had previously just used the PreProcessing script for my DSLR images - that was fine, but because everything was "hidden under the hood" so to speak, it was difficult for me to know what to try when things went wrong.  

One (hopefully) constructive comment that I would make - I shot my data with the RGB images binned at 2x2.  In your tutorial you do touch upon binning (in the PreProcessing Script section).  As a total beginner, I would have liked a bit more information about combining binned colour with 1x1 Luminance.  I did get there in the end, but I'm not 100% sure I did it right (see next paragraph). 

I followed the earlier version of your tutorial (when CC was done before Calib), and I wonder if this led to the issue that I now have - see http://stargazerslounge.com/topic/248698-calibrating-2x2-binned-images/ - namely strange artefacts in a numbr of the stars in my image.  I don't know if running Cal before CC would help with this problem or not.  I wondered also if Drizzling x2 (as you suggest in the tutorial) would help.  If anyone could suggest what they think I should try first, I would be very grateful.

In any event, thanks again for the excellent tutorial.

Regards

Steve

[gnomus]

Firstly, let me say thank you very much for this tutorial.  As someone who is just starting out with CCD imaging, it has proven to be extremely helpful.  I followed your tutorial for my first CCD image and was certainly pleased with the Luminance image that resulted.  I also ended up with a much better understanding of how and why the various dark, bias, flat and light frames should be combined.  I had previously just used the PreProcessing script for my DSLR images - that was fine, but because everything was "hidden under the hood" so to speak, it was difficult for me to know what to try when things went wrong.  

One (hopefully) constructive comment that I would make - I shot my data with the RGB images binned at 2x2.  In your tutorial you do touch upon binning (in the PreProcessing Script section).  As a total beginner, I would have liked a bit more information about combining binned colour with 1x1 Luminance.  I did get there in the end, but I'm not 100% sure I did it right (see next paragraph). 

I followed the earlier version of your tutorial (when CC was done before Calib), and I wonder if this led to the issue that I now have - see http://stargazerslounge.com/topic/248698-calibrating-2x2-binned-images/ - namely strange artefacts in a numbr of the stars in my image.  I don't know if running Cal before CC would help with this problem or not.  I wondered also if Drizzling x2 (as you suggest in the tutorial) would help.  If anyone could suggest what they think I should try first, I would be very grateful.

In any event, thanks again for the excellent tutorial.

Regards

Steve

Please ignore this post.  I was getting ahead of myself in PixInsight and combined my L, R, G & B incorrectly.  When I did it correctly, the bizarre artifacts in my stars disappeared.  Having now processed one image, I can see that the way in which binned data is combined with the luminance is relatively straightforward, and does not need any amplification.  Thanks you again for your tutorial.  I will be coming back to it again and again, I think.

[Gib007]

Please ignore this post.  I was getting ahead of myself in PixInsight and combined my L, R, G & B incorrectly.  When I did it correctly, the bizarre artifacts in my stars disappeared.  Having now processed one image, I can see that the way in which binned data is combined with the luminance is relatively straightforward, and does not need any amplification.  Thanks you again for your tutorial.  I will be coming back to it again and again, I think.

Thank you for your comments Steve, I appreciate them. I'm glad your issue is resolved - I've only just read your post so never got round to helping! I will look over the binning bit in my tutorial to see if a few extra bits will help smooth out the explanation. Thanks for your tip!

[gnomus]

Thank you for your comments Steve, I appreciate them. I'm glad your issue is resolved - I've only just read your post so never got round to helping! I will look over the binning bit in my tutorial to see if a few extra bits will help smooth out the explanation. Thanks for your tip!

No... thank you! I managed to gather some more data, and once again used your tutorial. It was much quicker second time around, and I ended up with something that I was reasonably happy with (as a first attempt). I think I will probably keep doing things manually from this point forward. My star artefact 'issue' I think was down to combining images before drizzling. Everything was fine after that. I hadn't appreciated how important drizzling was.

[Gib007]

Readers please note that the website address for this tutorial is now:

http://www.lightvortexastronomy.com/tutorial-pre-processing-calibrating-and-stacking-images-in-pixinsight.html

[Gasman]

Hi Kayron

Just noticed your post re Pixinsight processing. I`m used to using Astroart5  for processing my fits images and have been very happy with that although I have registered a copy of Pixinsight I`ve never really had the time to learn it properly thinking its a steep learning curve and put it on the `todo` list. I`ve recently bought a new Nikon DSLR and been experimenting with its .nef files with DSS but ending up with an image needing much processing to get rid of its background glow but I`m wondering if your tutorial might be able to help with processing Raw .nef files and maybe kick start me into Pixinsight again.

Just downloaded the tutorial to read and try and hopefully I can equate it to DSLR files!.

cheers

Steve

[Gib007]

Hi Kayron

Just noticed your post re Pixinsight processing. I`m used to using Astroart5  for processing my fits images and have been very happy with that although I have registered a copy of Pixinsight I`ve never really had the time to learn it properly thinking its a steep learning curve and put it on the `todo` list. I`ve recently bought a new Nikon DSLR and been experimenting with its .nef files with DSS but ending up with an image needing much processing to get rid of its background glow but I`m wondering if your tutorial might be able to help with processing Raw .nef files and maybe kick start me into Pixinsight again.

Just downloaded the tutorial to read and try and hopefully I can equate it to DSLR files!.

cheers

Steve

Hi Steve,

NEF image files are not a problem for PixInsight. It supports dozens upon dozens of image formats, including all DSLR RAW formats (which includes NEF). You can choose to either keep working in the NEF format or convert to FITS (or any other) as you process in PixInsight. It is up to you!

In your position, I'd calibrate and stack the images in PixInsight and while this is done, have the processes save the images as FITS files. By the end of pre-processing (calibrating and stacking), you'd then have a set of FITS images you can post-process. 

Best Regards,

Kayron