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Old 05-04-2012, 10:03 AM
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allan gould
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Perfect gradient removal

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
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  #2  
Old 05-04-2012, 10:32 AM
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jjjnettie (Jeanette)
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Cheers Allan.
I shall peruse the linked document for aforesaid enlightenment.
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Old 05-04-2012, 10:44 AM
Poita (Peter)
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I have an image this has been waiting for. I'll give it a go tonight.
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Old 05-04-2012, 10:48 AM
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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.
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Old 05-04-2012, 10:53 AM
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h0ughy (David)
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DBE works wonders in my opinion but will have a look at this
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Old 05-04-2012, 12:25 PM
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Quote:
Originally Posted by jjjnettie View Post
Cheers Allan.
I shall peruse the linked document for aforesaid enlightenment.
Peruse away, triple J
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Old 05-04-2012, 12:33 PM
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allan gould
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Quote:
Originally Posted by Poita View Post
I have an image this has been waiting for. I'll give it a go tonight.
Excellent, let us know how it goes.
Quote:
Originally Posted by cventer View Post
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.
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.
Quote:
Originally Posted by h0ughy View Post
DBE works wonders in my opinion but will have a look at this
I would use DBE for nebulosity - but I found this very easy to use for defined objects
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