Hemisphere:  Northern  ·  Constellation: Lyra (Lyr)  ·  Contains:  IC 1296  ·  M 57  ·  NGC 6720  ·  PK063+13.1  ·  Ring Nebula
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M57 (SHO), 



    
        

            Linda
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Getting plate-solving status, please wait...
M57 (SHO), 



    
        

            Linda
Powered byPixInsight

Imaging telescopes or lenses: Planewave CDK14

Imaging cameras: Finger Lakes Instruments Proline 16803

Mounts: Astro-Physics 1600GTO

Guiding telescopes or lenses: Planewave CDK14

Guiding cameras: ZWO ASI174MM

Software: Starkeeper Voyager  ·  Pleaides Astrophoto PixInsight 1.8 Ripley  ·  PHD2

Accessory: Innovations Foresight ONAG


Dates:June 4, 2020June 14, 2021June 15, 2021June 16, 2021June 17, 2021June 18, 2021June 19, 2021June 20, 2021June 21, 2021June 22, 2021June 23, 2021June 24, 2021

Frames:
Astrodon Ha: 26x900" (6h 30') -20C bin 1x1
Astrodon O: 28x900" (7h) -20C bin 1x1
Astrodon S: 27x900" (6h 45') -20C bin 1x1

Integration: 20h 15'

Darks: 40

Flats: 48

Flat darks: 40

Bias: 40

Avg. Moon age: 9.29 days

Avg. Moon phase: 64.97%


RA center: 18h53m32s.905

DEC center: +33°0137.23

Pixel scale: 0.728 arcsec/pixel

Orientation: -88.323 degrees (flipped)

Field radius: 0.179 degrees

More info:Open 


Resolution: 1296x1206

Data source: Own remote observatory

Remote source: Sierra Remote Observatories

Description

We all know the ring. It's an iconic image that we've all seen pictures of in books and on the net. What I didn't know until I turned the Planewave telescope at SRO on it was that there was this outer ring that was much fainter than the inner ring. When I took the test shot I knew I had to give it a try. On the way I learned three things:

1. The Ring is a small target even for 2560mm focal length.

2. Processing to bring out the outer ring and retain detail in the inner ring was hard. Really hard.

3. It may not have been worth getting the SII. It's there but swamped by Ha and OIII.

I lost count of the number of times I backed up and started from some point where I decided I had made a bad decision, only to back up again. And, again. And...well you get the idea.

This is the path I finally went down:

For each master:

WBPP

Dynamic Crop

MLT noise reduction

Deconvolution

Channel Combination (SHO)

For the SHO:

Cloned twice (call them SHO_A and SHO_B)

TGV Denoise

Masked Stretch to bring out the outer ring

Pixel math using the mask SHO_A_L to combine SHO and SHO_A_L

Curves

HDRMultiscaleTransform

for SHO_A:

Histogram stretch to bring out the inner ring

created a Lum mask of SHO_A call it SHO_A_L

starnet

pixel math to combine with SHO_B

Curves for contrast

Adv Sharpening

for SHO_A_L

starnet

convolution to blur the mask

increase the mask contrast

for SHO_B

stretch until the stars were at an aesthetically pleasing level

I'm hit and miss with starnet. Sometimes it does a good job and sometimes it leaves the nebula full of macro block-like artifacts. It did that on the mask but convolution blurred them out which was fine. On earlier processing paths I tried starnet only to get an unusable result. I wish I could predict whether it was going to do the right thing. Thankfully it did on the version stretched for the outer ring because that stretch quite bloated the stars.

This is a link to a video I did about the process of working on this image:

https://www.youtube.com/watch?v=6lxRM09iUz4

Comments

Revisions

  • M57 (SHO), 



    
        

            Linda
    Original
  • Final
    M57 (SHO), 



    
        

            Linda
    B
  • M57 (SHO), 



    
        

            Linda
    C
  • M57 (SHO), 



    
        

            Linda
    D
  • M57 (SHO), 



    
        

            Linda
    E

B

Description: Just a bit more curves adjustment

Uploaded: ...

C

Description: This was the HSO version mentioned in the video that was the first attempt.

Uploaded: ...

D

Description: This was the second version mentioned in the video. It moved to the SHO palette and was more successful than the first but still not quite what I wanted.

Uploaded: ...

E

Description: This is the HOO version shown in the video. This is just a remapping of the final SHO version created by moving H to red, discarding S and moving O to G and B.

Uploaded: ...

Sky plot

Sky plot

Histogram

M57 (SHO), 



    
        

            Linda