PixInsight Forum (historical)

PixInsight => Gallery => Topic started by: vol.patrick on 2014 April 24 22:45:30

Title: NGC7023
Post by: vol.patrick on 2014 April 24 22:45:30

Hi,

I took this photo on April, 9th, 2014, Moon visibility being 65%.

http://astrob.in/92520/0/ (http://astrob.in/92520/0/)

Imaging with a DSLR, I'am not happy with the background . Is it due to the Moon, or to my workflow ( or both)?. Can I do better?

Any comment or suggestion to improve my treatment will be appreciated.

Thanks

Patrick

Title: Re: NGC7023
Post by: georg.viehoever on 2014 April 25 14:52:39

If you want others to try, you'll need to provide the fits or raw files.

Title: Re: NGC7023
Post by: vol.patrick on 2014 April 25 23:24:58

Here is the link to the FIT file from the stacking of 106 images of 180s.

https://dl.dropboxusercontent.com/u/86018302/RGB.fit (https://dl.dropboxusercontent.com/u/86018302/RGB.fit)

May be I should have posted it in the Challenge section of the forum?.

Many thanks

Patrick

Title: Re: NGC7023
Post by: Nocturnal on 2014 May 07 15:13:16

Hi,

looks like you did not flatten your image. Without that you'll have trouble creating an image that looks nice in the center and on the edges.

Title: Re: NGC7023
Post by: Geoff on 2014 May 08 23:52:29

The nebula looks quite noisy--try more exposure. Also the colours are quite weak.  Try a saturation boost with curves after masking out the background.
Geoff

Title: Re: NGC7023
Post by: TobiasLindemann on 2014 May 09 11:57:54

Hi Patrick,

I had a try on your image.
http://www.tracking-station.de/zeigl/IrisPatrick.jpg

Although your data is not perfekt, it is good enough to create a nice picture. But I think you should invest in a coma corrector. It is not expensive and makes the picture really more aesthetic.

My workflow:
- auto-STF with unlinked channels
- DBE (because of the dark clouds it is not easy - try to set the samples by hand in the dark regions)
- drag the little triangle of the STF to a HistogramTransformation process
because of the strong gradients the background is still to colourful
- make a rage mask to protect the mid-tones and the highlights
- open a CurvesTransformation and decrease the chrominance, to neutralize the background more
- invert the mask and increase the chrominance, to boost the colors in the nebular

Surely you can do more processing, but I hope it helps you a little bit.
Please feel free to ask, if you have any questions.

Greetings
Tobias

Title: Re: NGC7023
Post by: vol.patrick on 2014 May 18 11:56:35

Hi,
Thanks for your advices.
I'm sorry for the late answer, but I had been out of town for a while.

I just realized that in the DSLR RAW format préférences,

I had checked "Create RAW Bayer image...  RGB Image,
instead of "Create raw bayer CFA image.. Monochrome image".

I believe that caused  among other things the background to be colourful, specially in the red channel.
Anyway, I'll give it another try and apply your advices.

Thanks again

Patrick