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Pelican : Hubbled


Uranium235

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Just finished processing this one. It was clear last night so I was able to finish off the SII channel and add a few more SII before the cloud rolled in at about 11.30. As usual, the red channel has been a bit of a pain, but not because of star bloat (I found that the pelican had rather a lot of SII), but because I had slightly eggy stars, so I had to heal a few stars that were displaying red halos.

When I merged the channels and balanced them, it was a surprise to see it wasnt very "green" like HST colour images usually start off - so there was very little I needed to do in terms of selective colour. Still no cure for the halos on the brighter stars though, I suspect it might be a filter problem.

Anyways, enough rambling - cut to the money shot! :)

IC5070: Pelican Nebula (HST Colour)

L_Ha(22x450), R_SII(14x450, G_Ha(14x450), B_OIII(14x450)

ED80 (0.85x), Atik 314L+

Setpoint -10

Thanks for looking :)

Rob

attachment.php?attachmentid=71004&stc=1&d=1318878961

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I love the colours you have achieved on this shot. My only thing with it, is that you seem to have lost some of that deep 3D feel at the bottom left that you had with your previous post - Don't know why. Lovely looking shot though.

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I really like this one - very subtle colouring.

Hope you don't mind but I have attacked the two major halos as you mentioned them in your text. In case it is of any interest, this is what I did in PS:-

1. Filter - Noise - Reduce Colour Noise (100%)

2. Image - Adjustments - Replace Colour. I selected the purple halo and set fuzziness to 146. Adjust Hue to get closest match to background and adjust saturation to get as close a match as possible.

3. Although I didn't think to do so in the image I enclosed, part 1 reduced overall saturation a little so in a subsequent look, I addressed this using Image - Adjustments - Match Colour and increase Colour Intensity to match the original image

post-13675-133877680146_thumb.jpg

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That is a really interesting image. So much more revealing I think than the usual shots we see of this.

Absolutely love it! Well done.

I would be very interested in seeing the different filter stacks? Any chance? off list if need be.

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Sara, I think this differs slightly from the HOO version becuase after merging the RGB and Luminence, I applied and additional curve to bring out more of the top left and right. A case of swings and roundabouts I think (lose something to get something).

Steve, many thanks for the pointers on how to reduce those purple halos - actually, youve done a really good job on it! :) I will have a go myself later on to see if I can replicate the method. Definitely worth a beer I think!

Mick, no problem mate. I will put up the individual channels later on. I think Ant might be interested in getting them too for his narrowband project (if he hasnt already got the pelican).

Rob

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Hi Rob, you'll notice that the Colour Noise Reduction has also smoothed the image (too much!). To avoid this, duplicate the original layer first and carry out the above procedure on the new top layer. When you are happy with the halos, convert the top layer to a layer mask (hidden) and then brush in the stars using a 50% opacity and 40% flow making several passes of the brush to reveal the non-haloed stars.

This way you keep your original sharpness and lose the halos.

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Hi Rob, you'll notice that the Colour Noise Reduction has also smoothed the image (too much!). To avoid this, duplicate the original layer first and carry out the above procedure on the new top layer. When you are happy with the halos, convert the top layer to a layer mask (hidden) and then brush in the stars using a 50% opacity and 40% flow making several passes of the brush to reveal the non-haloed stars.

This way you keep your original sharpness and lose the halos.

Thanks Steve, I will remember to do that.

Earlier on I noticed why I might have had a problem with my SII star shapes. The reducer wasnt sitting flush to the focuser drawtube, and a bit skew-iff (-50 points for not checking this before starting!). Hmmm... this is why I dont like the cheapo locking screws you get on these scopes, I'd prefer a nice compression ring instead.

It may be clear tonight, so I could possibly add yet more OIII and SII to bring the number of subs to the point where I can use sigma clipping, before moving onto M45 to give it a good thrashing :)

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Have now finished the final stack and process, details are as follows:

Ha_L(22x450), SII_R(18x450), Ha_G(16x450), OIII_B(17x450)

Will include the channel files too, and all have had exactly the same curves applied. No purple halos either :) Shame I didnt have time to move onto M45 becuase it clouded over... boooo indeed.

attachment.php?attachmentid=71109&stc=1&d=1318976145

Channel files in the order of SII/Ha/OIII

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