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Bubble Nebula reprocess

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#1 Peter in Reno

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Posted 05 February 2013 - 01:27 AM

After practicing and processing other people's images, I went back to re-process Bubble Nebula I captured last Aug-Oct 2012.

High Resolution: Bubble Nebula in HST . Click on the image to zoom.

There seems to be so many ways to process in HST. My previous process removed all green and eventually I felt it didn't look right. So I preserve some green which came from Ha to make more colorful look.

Any comments or critiques welcome. Thanks for looking.

NGC7635: Bubble Nebula Hubble Palette in Cassiopeia. 0.47"/pixel. 8/24/2012, 9/7/2012, 10/6/2012.

Astrodon Ha 5nm filter: 21 x 15 minutes, 1x1, Excellent seeing condition. 8/24/2012
Astrodon Oiii 5nm filter: 31 x 15 minutes, 1x1, Not so good seeing condition. 9/7/2012
Astrodon Sii 5nm filter: 12 x 30 minutes, 1x1, Excellent seeing condition. 10/6/2012

Celestron 8" EdgeHD at F/10 with A-P Mach1GTO GEM. Atik 460EX mono. Hutech OAG. Lodestar.

Captured and pre-processed with Nebulosity. Stacked and post processed with PixInsight.
PHD settings: RA Aggressiveness: 60, RA Hysteresis: 10, Max Dec Duration: 75, Min Motion: 0.70, Calibration Steps: 125msec, Auto/Resist Switching, Extreme dithering and Settled at < 0.5, 3 - 4 sec guiding exposure.

Red = Sii, Green = Ha, Blue = Oiii

Thanks,
Peter

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#2 NorthBoundTrain

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Posted 05 February 2013 - 04:19 AM

Looking good Peter!
This was the target I choose for my first light back when I got my new SV80ST & 314L+ last year. I only had an Ha NB filter at the time, so I did a HaLRGB. I have been eagerly waiting to do it in full HST this season, now that I have the full set. Seeing this makes me even more anxious! :jump:

#3 Harel_Boren

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Posted 05 February 2013 - 04:46 AM

This looks very nice. Indeed the artistic input in HST is even larger than RGB, and you've done very, very well on that front :-)
Cheers,
Harel

#4 Peter in Reno

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Posted 05 February 2013 - 10:27 AM

Thanks guys.

This is my very first image with mono camera. NB filters really help capture under heavy light pollution. Capturing with LRGB filters is very difficult under LP.

Peter

#5 shams42

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Posted 05 February 2013 - 10:43 AM

Hi Peter,

Beautiful image. If you really do want constructive criticism, I would say that the Bubble and surrounds look over-sharpened and the background looks over smoothed for my taste.

#6 mcarroll

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Posted 05 February 2013 - 10:51 AM

Great work Peter! Yes, NB is a powerful way to battle LP.

#7 Peter in Reno

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Posted 05 February 2013 - 11:10 AM

Hi Peter,

Beautiful image. If you really do want constructive criticism, I would say that the Bubble and surrounds look over-sharpened and the background looks over smoothed for my taste.


Yes, I agree I over smoothed it a little too much. NB imaging makes the signal so weak that I had to over stretch the image to reveal DSO. This also caused to reveal more noise. So smoothing the background helped reducing noise at the cost of making them look too soft. Maybe I need to back off over smoothing a little bit.

I was experimenting with PixInsight Unsharp Mask to sharpen the image. The image ended a little too soft so I sharpened it in one pass and got greedy and decided to sharpen it a little more.

It seems that light pollution tends to soften the image. I have processed other people's images taken from dark sites and never needed to smooth or sharpen their images. It might be possible that focusing might be the cause but the stars look well focused.

Thanks for the comments.

Peter

#8 shams42

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Posted 05 February 2013 - 04:13 PM

Have you ever tried to sharpen using the high pass filter in photoshop? I find it a really powerful way to sharpen without adding a lot of artifacts. With layer masks you can just "paint" the high pass filter along the edges of interesting features.

PI's LocalHistogramEqualization works very well also -- it doesn't sharpen, but increases local contrast. I'd recommend using a range mask to limit its impact to bright areas.

#9 Peter in Reno

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Posted 05 February 2013 - 04:30 PM

I do not use PhotoShop. I have tried it for three years and I suck at it. Transitioning to PixInsight was the best move.

I use Multi-Scale Median Transform with Noise Reduction. This happens in between Color Calibration and Histogram Transformation. It's a cool noise reduction tool while the image is still linear and helps to stretch the image later on.

This image already used Local Histogram Equalization. I use it after HDR/Morphological and works quite well.

Peter

#10 dickbill

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Posted 05 February 2013 - 04:40 PM

Very nice resolution

#11 algady

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Posted 08 February 2013 - 04:12 AM

Very nice job, keep up Peter.

#12 mmalik

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Posted 08 February 2013 - 08:16 AM

Stunning Bubble; my close-up here...

#13 WhitenerJ

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Posted 08 February 2013 - 08:25 AM

Wow!!! That is very nice!! Amazing detail!!

Jason

#14 PatHolland

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Posted 08 February 2013 - 09:32 AM

Nice image Peter! I am anxious to get out and try the Atik 460EX (M) after seeing this image.

#15 Peter in Reno

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Posted 08 February 2013 - 11:45 AM

Thanks for the kind comments. I really enjoy my new Atik 460EX mono camera.

Peter






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