Trouble with NGC7023

[Twinkle Star]

Hello  ,
I have bought PI half a year ago and I got on rather well, until I started to process NGC7023.
After stacking (DSS) I load it in PI and checking the result with STF, I was most irritated . I saw something similar to waterwaves or circles around the center
of the image spreading outwards. You know, like when you throw a pebble into water and watch the waves that makes. This is what I see...

I have tried DBE several times, Background newtralzation, Color calibration, noise reduction techniques - nothing helps. Only in the histogram I am
able to control these waves a little, but as soon as I increase luminance or color, these "waves" are back again.
I am at the end of my wits....
What can that be and how can I handle this? Oh, yes, I remember that I took the picture at  nearly full moon - can that light pollution be
the reason for this? Can I save the picture or is there no help at all? I took the picture with my skywatcher 135 PDS, 600mm and NIKON D7000, ISO800, exposure time 1 hour.
I took another picture that same night of the blinking nebula and this image was ok....

Thanks for your advice / help,
Angelika

[Carlos Milovic]

First of all, use 32bit files all the time.
Now, a question... Are you seeing these "waves" with the STF or the RealTimePreview? Do they appear if you apply a histogram transform to a normal preview?

[Geoff]

Angelika, could you post a picture? It may be easier to diagnose if we can see the problem for ourselves.
Geoff

[Twinkle Star]

Hello,
how do I post a picture here? The direct attachment procedure does not work.
Thanks,
Angelika

[Carlos Milovic]

You may use the Endor server:
http://pixinsight.com/forum/index.php?topic=4039.0

[Geoff]

Hello,
how do I post a picture here? The direct attachment procedure does not work.
Thanks,
Angelika

Use the additional options button when posting.

[Twinkle Star]

Hello,
I have Managed to load the troublesome Image on the endor Server. Under Forum Shared Files you will find a Folder "DEEP SKY Iris nebula" and in there is the Picture "Irisnebel-DBE".

I think you can see  my Problem quite clearly. This Image is the raw sum in tiff Format where I only Usedom the DBE Funktion on (I changed it into jpeg to make it smaller).

Thank you very much in advance,

Angelika

[Geoff]

Really strange!  I guess the first thing is to see where the error is arising.  Do your uncalibrated raw images show this?  if "yes", then the problem lies with the acquisition.  If "no", then the problem lies with the processing.
Geoff

[Twinkle Star]

Hello Geoff,
I just had a look at my uncalibrated raw images before stacking - and they seem to be ok!!
So I don´t trust DSS. I will repeat the stacking procedure and check the settings.

Just one more question:
I have tried to stack with PI, but I hesitated because I noticed that I needed flats to stack with PI - is that true, or are my lights and darks sufficient enough?

Thanks so much,
Angelika

[Geoff]

Angelina, if you are using the BatchPreprocessing module it will issue a warning that you have no flats, but this is only a warning and it will go ahead and just use the darks and biases. If you are not familiar with this module, check out the video by Harry.
Geoff

[Twinkle Star]

Hi Geoff,
I just tried the Batch Preprocessing tool. -- But when I got the final picture, there was no colour any more. Background Neutralization did not work, because it can only be applied on coloured pictures.
What is wrong now? I used the settings from the video tutorial.
Thanks in advance,
Angelika

[Geoff]

Since you are using a one shot colour camera you will have to do some debayering. I know that the video mentions this right near the end, but I've never paid much attention to this bit as I don't need to do this.
Note added It may also be a good idea to look at this thread http://pixinsight.com/forum/index.php?topic=4503.0
Geoff

[Twinkle Star]

Hello Geoff,
I simply hat to tick the CFA option in BP and the color came out alright.
Thanks very much for your help through all this,
Angelika