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avandonk
12-12-2013, 09:00 AM
My observatory site is only 16km from Melbourne. Light pollution and gradients are a constant problem.

I have been learning how to use PixInsight concentrating on DBE or Dynamic Background Extraction.

The small images below are the before and after using DBE. You can see how bad the light pollution and gradients are in my sky.

Here is a large version of Rho O after using DBE. 14MB

http://d1355990.i49.quadrahosting.com.au/2013_12/RHO_DBE.jpg

The image needs more data but the improvement is spectacular even for a beginner at using PI!

Bert

allan gould
12-12-2013, 10:25 AM
Bert
Background modeling in PI was the main reason that I purchased PI as I have the same problem here in BrisVegas. Worth every cent in my opinion but with your ultra wide and fast system I can see how effective it is for you and it makes a stark difference.
Allan

Shiraz
12-12-2013, 10:26 AM
well that sure was worth the effort!

Larryp
12-12-2013, 12:16 PM
That's an amazing difference, Bert

multiweb
12-12-2013, 01:27 PM
Very impressive indeed. :thumbsup:

h0ughy
12-12-2013, 01:59 PM
that was my first reason for buying PI - there are a lot more since i got it

DavidNg
12-12-2013, 02:11 PM
Hi,
Great difference did the DBE make. Was DBE applied once or multiple repeats?

Regards
David

avandonk
12-12-2013, 02:17 PM
Only twice with judicious reparation!

Bert

gregbradley
12-12-2013, 05:14 PM
That is a huge difference. Did you use the auto DBE or did you manually model the background to target the area it affects?

Greg.

avandonk
12-12-2013, 08:57 PM
Greg it takes trial and error to set the parameters for the corrections. This is by no means an easy image as it is full of faint nebulosity and dust. In my humble opinion these guys are very smart. You just have to play with PI to get a feel of what is happening.

I did an initial DBE with auto generated samples. Saved the result and then was very careful where the image was sampled and then hit it hard.

It is a bit like riding at high speed on a motor cycle, one mistake and you crash!

This bloke Harry has some informative vids. Here


http://www.harrysastroshed.com/pixinsighthome.html


Bert

gregbradley
12-12-2013, 10:47 PM
I've used it a bit but by no means expert in it. Its a good approach and I like the way PI generates a 2nd image that subtracts from the main image.

There are similar approaches in Photoshop as well using a subtracted layer of the background gradient. That works well but only as well as you have a smooth copy of the background gradient to subtract. I imagine PI DBE goes the same way. It'll be as good as the model created to be subtracted.

Greg.

avandonk
12-12-2013, 11:13 PM
Here is an animated gif 2MB

http://d1355990.i49.quadrahosting.com.au/2013_12/DBE_.gif


Bert