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M57 - Pixinsight reprocess

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#1 bluedandelion

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Posted 04 November 2012 - 01:50 AM

M57, the Ring Nebula in Lyra. Captured in 2009 with a C9.25 at f/10 and a modified Canon 350D from a light polluted location. Total exposure was 45 minutes at ISO800. No filters were used.

This is a center crop.
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Ajay

#2 mmalik

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Posted 04 November 2012 - 04:07 AM

Very nice looking Ring Nebula. If not too much to ask, would you be able to describe PixInsight processing in detail for learning/documentation sake?

#3 srosenfraz

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Posted 04 November 2012 - 11:22 AM

That's an excellent Ring, Ajay. You have some great detail within the ring - nice job.

#4 bluedandelion

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Posted 04 November 2012 - 11:28 AM

Thank you Mike. There is actually more signal but I dare not stretch any more due to severe gradients due to light pollution.

Here's my workflow:

1. Preprocess (i.e. Apply Flats, Flat Darks & Darks and Debayer) with Nebulosity 3.

Everything else is done in PI

2. Register, Combine and Trim edges
3. Dynamic Background Subtraction
4. Color calibration
5. Noise reduction on unstretched image via Atrous Wavelets and Greycstoration
Steps 2-5 are on the unstretched image. You can see what you are doing by using the Screen Transfer function. Noise is kept low because it is not stretched.

6. Stretch image via Histogram transfer
7. Improve dynamic range via HDR wavelets
8. Local Contrast Enhancement
9. Improve saturation via curves
10. A little Unsharp mask

In some of these steps a Starmask or Luminance mask (or their inverse) was used. All these names make it sound daunting, but see Harry's tutorials for quick start recipes on most of these major steps.

Ajay

#5 petemumbower

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Posted 04 November 2012 - 11:37 PM

Great image Ajay, you have your C9.25 singing.

#6 bluedandelion

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Posted 05 November 2012 - 10:51 AM

Thank you Scott and Pete.

Ajay






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