New Video Tutorial | Nuevo Videotutorial: M42 by Harry Page (DBE/ACDNR/HDRWT)

[Juan Conejero]

Hi to all,

I've just uploaded a new video tutorial to our website: An Introduction to the DynamicBackgroundExtraction, ACDNR and HDRWaveletTransform Tools in PixInsight, with raw M42 data acquired by Harry Page.

This tutorial has been divided into two parts. A first part about the DynamicBackgroundExtraction tool is now available:

http://pixinsight.com/videos/

The second part describes a relatively simple but effective processing strategy based on the ACDNR and HDRWaveletTransform tools. It should be available within the next 48 hours.

Thanks to Harry Page for proposing this nice image, and for allowing me to use it in this tutorial.

We hope you'll like it and find it useful.

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Hola a todos

Acabo de subir un nuevo videotutorial a nuestro sitio web: An Introduction to the DynamicBackgroundExtraction, ACDNR and HDRWaveletTransform Tools in PixInsight, (sólo en Inglés) con datos raw adquiridos por Harry Page.

Este tutorial ha sido dividido en dos partes. Una primera parte sobre la herramienta DynamicBackgroundExtraction ya está disponible:

http://pixinsight.com/videos/

La segunda parte describe una estrategia de procesamiento relativamente simple pero efectiva, basada en las herramientas ACDNR y HDRWaveletTransform. Debería estar disponible durante las próximas 48 horas.

Gracias a Harry Page por proponer esta bonita imagen, y por permitirme utilizarla en este tutorial.

Esperamos que os guste y que os resulte útil.

[ManoloL]

Hola a todos:
Muchas gracias, Juan,  por el tutorial y en mi caso por el texto escrito que me ha permitido comprender lo expuesto.
Yo tengo que confesar que cuando he obtenido imágenes que al estirarlas se han convertido en psicodelicas como las que se ven en el ejemplo, cosa que vengo atribuyendo al uso del IDAS-LPS,  he creído que eran irrecuperables.
Menos mal que no las he borrado. Tendré que dar un repaso a mis archivos.

[Harry page]

Hi Juan

Thanks for your latest installment on the M42 tutorial, very informative for us mere mortals!
I await the final installment in this thrilling series ( ok I might be overdoing it)  :lol:

[Harry page]

Hi Juan

Thanks for the last installment of the tutorial, it looks very good and will report back when my brain
catches up with it

Regards Harry

[Juan Conejero]

Thank you Harry. I'm glad to know you like it.

Stay tuned! More videos are to come!

[Harry page]

Hi Juan

Have sort of digested information in video's
I find these very helpful showing how to work with images like mine, which as you say lacks signal, but that's what most of us amateurs struggle to get.

Anyway here is my go    http://www.harrysastroshed.co.uk/CCD%20HTML%20PIC/M422009.HTML

I can assure you this is a lot better than before your tutorial!

How about some guide how to get some colour back into the bleached stars?

Many thanks for your continued efforts on the pixinsight front

regards Harry


By the way viewers there is another 5 hrs more data in my version than Juan had to work with

[Juan Conejero]

Hi Harry,

Very nice improvement!

I think you should gain more control over noise reduction though. In this regard, I see two things that can be improved:

- Try to avoid excessive noise reduction on mean-signal image features. This requires fine tuning ACDNR masks. For example, I refer to the region between M42 and the Running Man. If these features are too smoothed, the image gets a sort of "plastic" look.

- Don't try to boost the background too much. Large-scale noise appears on the background as "dark holes" due to insufficient signal.

This image is not an easy target for noise reduction, by no means. In fact, I must confess that I had a very hard time trying to achieve a reasonable result from noise reduction. The main problem is of course weak signal, as always, but in this case it's way much worse because the brightest parts of the image have no noise at all. Then we have to fight against tons of noise in regions that are touching other regions with no noise at all. Pretty challenging. If you look at the ACDNR masks that I used in the tutorial, you'll see that they have almost no white pixels!

To process your five-hour image, I'd consider building noise reduction masks manually with CurvesTransformation, instead of using ACDNR's integrated mask. With curves you have much more freedom to fine tune mask protection for intermediate zones. Definitely, a histogram transformation (which is what ACDNR's mask does) does not suffice in this difficult case. Also perhaps I'd consider more than two applications of ACDNR, and quite probably a final (and gentle!) noise reduction with GREYCstoration.

Hope this helps. You have a very nice challenge here. This image can teach you a lot of things

[esraguin]

Hi Juan

              Thanks for the latest video ,I have collected some nice data of m42 with my SC8in Meade ,194x15sec subs which DeepSky Stacker stacked 184, signal to noise on different parts of the image was of interest to me, as my image covers the very core of m42 signal seems to be strong, so will give it a go with some of the processes on the video.

Thanks for all your hard work.

Alex Wilson

[Harry page]

Hi Juan

Many thanks for the input and make the following observations

1) The image I provided for you to work on was 7 hrs long mine was 12 hrs ( Data is hard won in the
     orange glow)

2) I agree I have over done it on the noise reduction part and need to spend more time on this.

3) The background stretch I find is always a grey area and peoples opinion varies quite a lot on this
    and I find in this image of mine there is no true back ground and  there is dark nebula everywhere ,  
    perhapes I need to reconsider this point !

4) Perhapes I am getting gready about what I am expecting to get from my images, as what I am able to  
     achieve with pixinsight far excedes what I could do with photoshop  ( With your help anyway )


Please keep up the fantastic work as it much appeciated


Regards Harry


P.s.   Got any Ideas on the bleached stars ?