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allan gould
05-04-2012, 11:03 AM
Having tried a few gradient removal programs, however I never felt that they were right on the ball and that includes PixInsight DBE and Gradient Xterminator etc.
While browsing the web I chanced upon this procedure which I can highly recommend for removing complex gradients in mono or colour. http://www.flemingastrophotography.com/gradients.html

I've attached a recent effort of capturing the Leo triplette with my 5"apo while the moon was right next to the object at about 75% illumination.
After flat and bias removal etc there is still a horrendous gradient from light pollution from the neighbours lights and the moon (second image). Using the above procedure I was able to remove all traces to my satissfaction and recover an acceptable image.
Worth a try in my opinion and I hope this is of value to others.
Allan

jjjnettie
05-04-2012, 11:32 AM
Cheers Allan. :)
I shall peruse the linked document for aforesaid enlightenment. :)

Poita
05-04-2012, 11:44 AM
I have an image this has been waiting for. I'll give it a go tonight.

cventer
05-04-2012, 11:48 AM
Nice. I will give it a go. I suspect its easier to do on somethign like a galaxy.

Busy field with lots of nebulosity and stars would be difficult to use this technique.

Nice leo triplet by the way. When do we see the finished product. Very cool that thats from 5" apo.

h0ughy
05-04-2012, 11:53 AM
DBE works wonders in my opinion but will have a look at this

allan gould
05-04-2012, 01:25 PM
Peruse away, triple J

allan gould
05-04-2012, 01:33 PM
Excellent, let us know how it goes.

yeah, I use it mainly for galaxies ATM and I suspect you are right that Nebulosity would be difficult. The moon is right on the triplette at the moment and so it will have gone by the time my qhy10 gets back so I'll capture the colour with that. I should mention that I used the WO p-Flat IV on the scope to get the field of view that I wanted.


I would use DBE for nebulosity - but I found this very easy to use for defined objects