Hello to all:
It is Crescent Nebula has 168 minutes with subs of 7 minutes, for 12 with filter Ha and 12 but with filter Oiii , soon I synthesized a photo but, in Photoshop, to create 3er. RGB channel, because with the filter Sii, there is no signal in this object.
Thank you very much to happen to see the photo.



Many greetings
Cesar

__________________
____________________________________
http://www.astrophoto.com.mx

Nice image but needs to have a strong blue and weaker green gradient removed. Russ Cromin's GradientXterminator is a great addition to Photoshop for this though for something as strong as in this image Carboni's Astronomy Tools>Soft Color Gradient Removal will do the job quite nicely. The teal cast that fades as it goes from lower right to upper left will be removed but the similar colors in the nebula will remain.

Note these two methods are very different and you need both in your set of tools.

I can post the corrected image with your permission or PM me your email address and I'll send it directly to you so you can see what I'm talking about.

Rick

Good wide capture of all the dust in the area.

Robert

Hello Rick:
Thank you very much.
By all means you can post the image modified by you.
As for me, and thanks to your commentaries, I cleared that gradient with PixInsight.
I would like to continue having you opinion.



Many greetings
Cesar

__________________
____________________________________
http://www.astrophoto.com.mx

Hi Cesar, Like Robert said very nice wide shot region. Very nice color combo, looking forward to see the final results. Clear Skies

Improved but you need to watch the histogram when processing. It is severely distorted and has been clipped at the dark end meaning data lost. I can't post a full size image as it goes over bandwidth. If you want that PM me your email address and I'll send it that way. I don't like putting large images directly into the message to avoid bandwidth limits as dialup users can be hit hard with charges in some parts of the world by this as well as being forced to take needless time downloading an image they didn't want to download.

I've attached a small image reprocessed purely by using Astronomy Tools soft gradient removal tool and a bit of work on the contrast using curves in Photoshop. I've also attached your original histogram, the histogram from your improved image and the one from my final image. Note that the distortions and clipping have been corrected as best as I could. Without original data that lost data is unrecoverable and working with 8 bit data is severely limiting as well. Still the last histogram shows what you should end up with when working with the original data. Note too that the peaks of the three colors should pretty well match as to width and location. This is the case even when one color (usually red or blue) dominates the final image. In that case the width of the peak will be a bit wider and the right going tail thicker in the dominant color but the centers and left fall off should normally be about the same. If they aren't something is usually wrong in the color balance of the image. My histogram still shows an odd hump in the blue and a bit of one in the green. Likely means the gradient removal left a little that needs to be removed but without original data (I do best to remove the gradients in the three monochrome color images before combining to avoid this problem) and without using the more complex GradientXterminator this was the best I could do using Astronomy Tools and curves -- the latter takes some practice, go slow and make many small adjustments not a few big ones.

Rick

Attached Images

	mexhunter-2s.jpg (132.0 KB, 4 views)
	M-HISTO-ORIG.gif (6.4 KB, 2 views)
	M-HISTO-ORIG1.gif (6.1 KB, 2 views)
	M-HISTO-new.gif (5.5 KB, 1 views)