Orion

Image Critiques Nightscape & Astro Critiques
1

Orion_NPN.jpg
Orion_NPN.jpg1200×1500 1.87 MB

Critique Style Requested: Standard

The photographer is looking for generalized feedback about the aesthetic and technical qualities of their image.

Description

The Orion constellation. Photographed in spring as it was setting near the western horizon from a Bortle 4 sky near my home.

Specific Feedback

Any feedback on how to reduce the noise would be much appreciated. I was particularly interested in trying to capture Barnard’s Loop, which seems like I did, but its quite noisy.

Would more sub images help in reducing the noise?

It seems like no matter what I do the more images I take the more blown out the Orion nebula becomes. Is there a way to combine the subs so that the Orion Nebula stays intact while the fainter structures are brought out?

Would photographing the nebula alone with a longer lens such that the detail in it is retained, and then scale it down in size and compositing it back into the wider view work?

Does the image have enough contrast or should the blacks be darker?

Technical Details

Nikon D850, Nikon 50 mm f/1.8 MF, ISO 800, RAW
20 sub frames at 120 seconds each. Each RAW file was edited in ACR. The RAW files were very bright, my guess due to light pollution, so I needed to make the following adjustments to bring out details: Highlights -100, Shadows +100, Whites -100, Blacks -100. Then I used ACR Denoise and saved each sub as a DNG. These 20 DNG files were then brought into Siril to register and stack. Then I removed Green Noise, and did a Background Extraction. Siril could not plate solve the image so I could not do a photometric color calibration. I am starting to think Siril is just not capable for that task. I then used StarNet++ to separate the stars from the image. I brought the starless image into PS to make adjustments. Then back into Siril for Star recomposition. Once the stars were incorporated back in, it was back into PS for final adjustments.

I also tried to remove noise using one of Siril’s routines,

Critique Template

Use of the template is optional, but it can help spark ideas.

  • Vision and Purpose:
  • Conceptual:
  • Emotional Impact and Mood:
  • Composition:
  • Balance and Visual Weight:
  • Depth and Dimension:
  • Color:
  • Lighting:
  • Processing:
  • Technical:
2

Wow – quite a detailed capture! Barnard’s Loop remains one of my failings. I’ll try again soon if we ever have a clear dark sky again. I need to fit my 28 mm lens on my tracker and astro camera with its APS-C sensor size. But focusing is about impossible with that rig so maybe it’s better to use the R5.

For me, there is no decent denoise option other than stacking. I assume Siril should average the noise, so don’t see why to use any denoise thing first. It will likely trade “clean” noise for artifacts. Just for comparison try Sequator (Windows) or Starry Landscape Stacker (Mac) for comparison. 20 subs should come out very clean.

Then after the noise issue, there is the dynamic range. The nebula itself (M42) is said to be the most challenging object for its huge dynamic range, but at the small size here you are not so concerned about bringing out all its faint detail. If the subs were overexposed it would be blown out. Maybe try two different exposures and composite. Or as you suggested, shoot it separately and scale down. But even PixInsight is challenged to handle its dynamic range. I have subs from over a year ago that I haven’t processed because I need to figure out a method that I have seen videos on but have yet to really try. I don’t know if it is exclusive to PI. If I ever get around to trying it I’ll post the result and some info. Or you could find the method by searching for processing M42. Adam Block has a video and I think I’ve seen others.

PixInsight won’t plate solve my wide-angle stuff either. But with camera lenses and sensors I doubt color calibration is important. Just make it look pleasing. The Big Boys do that with a free hand.

3

Thank you for the EP!