Barnard 150 - The Seahorse Nebula: Processing Walkthrough

Written By Patrick A. Cosgrove

My Image of Barnard 150 - The Seahorse Nebula

(All Processing is done in Pixinsight, with some final touches done in Photoshop)

1. Blink

  • Lum

    • 13 frames removed for thin clouds

  • Red

    • 6 frames removed!

  • Green

    • 7 Frames removed for clouds.

  • Blue

    • 6 Frames removed for clouds.

  • Darks

    • All looks ok

  • Dark Flats

    • All looks ok

  • Flats

    • all good

2. WBPP 2.8.9

  • Reset everything

  • Load all lights

  • Load all flats

  • Load all darks

  • Select - maximum quality

  • Reference Image - auto - the default

  • Select the output directory to wbpp folder

  • Enable CC for all light frames

  • Pedestal value - auto

  • Darks -set exposure tolerance to 0

  • Lights - set exposure tolerance to 0

  • Lights - all set except for a linear defect

  • set for Autocrop

    WBPP run 2:42:08 - no errors

WBPP Calibration View

WBPP Post Calibration View

WBPP Pipeline View

3. Load Master Images and Create Color Images

  • Load all master images and rename them.

  • Using CombineChannels, create the Master RGB image

Master L, R, G, and B images.

Initial RGB Color Master Image.

4. Initial Process of Linear RGB data

  • Run DBE for the RGB linear image. Use subtraction for the correction method. Choose a sampling plan that avoids the nebulae.

  • Run BXT - correct only. This cleans up and stars at the corners.

  • Select a preview rectangle sampling the background sky and then set up and run SPCC.

    • Use the 571 device curve

    • Use ZWO R, G, & B filter curves,

  • Run Full BXT - I am using default values here as I do not want to shrink the stars too much - I want them bigger to be better seen through all of the narrowband nebulae.

  • Run NXT V3 - see params from snapshot below

  • Run SXT and save the RGB stars.

Master RGB Image DBE Sampling Plan (click to enlarge)

MasterRGB- Before DBE (click to enlarge)

Master RGB after DBE (click to enlarge)

Background Subtracted by DBE (click to enlarge)

SPCC Panel Settings

SPCC Regression Results

Master RGB image before SPCC (click to enlarge)

BXT Settings Used.

Master RGB after SPCC (click to enlarge)

NXT Panel used.

SPCC Regression Result (click to enlarge)

BXT Parameters used.

NXT Parameters used.

Before BXT Fix Only (Copy)

Get Filter Config

Master RGB Before BXT Correct Only, After BXT Correct Only, After SPCC, After BXT Full, After NXT V3

Final Linaer RGB image.

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Master RGB Stars Only

6. Process the Linear SHO Data

  • Run DBE for the SHO linear image. Use subtraction for the correction method. Choose a sampling plan that avoids the nebulae.

  • Run BXT - correct only. This cleans up and stars at the corners.

  • RUN PFSImage to get the star sizes. X = 1.81, Y= 1.92

  • Run Full BXT -I used values very close to the measured star sizes. See the panel snapshot below for the params used.

  • Run NXT V3 - see params from snapshot below.

  • I had a lot of trouble getting the color I wanted from this image. I tried manual methods and the NarrowbandNormalization script, but I couldn’t achieve the desired result. Then I had a thought. SPCC can be used with Narrowband images, but I had never tried it. When I gave it a go at first, I thought it looked terrible! All dark Green! But then I did an STF Update, and suddenly there was the image I had been looking for!

  • Select a preview rectangle sampling the background sky and then set up and run SPCC.

    • Use the 571 device curve

    • Define the filter specs from my Astronomiks narrowband filters.

    • Check Narrowband mode

    • Check the color calibration box.

    • Run

    • Update STF on the new image.

  • Run SXT and save the RGB stars.

Starting SHO Image.

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Before DBE (click to enlarge)

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Mastr SHO DBE Sample Patern (click to enlarge)

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SHO after DBE and fresh STF. (click to enlarge)

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SHO background removed (click to enlarge)




Results from PFSImage

BXT Params Used

NXT V3 params used.

Before BXT (Copy)

Get Filter Config

Master SHO before BXT Correct Only, After BXT Correct Only, After BXT Full, After NXT V3

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Master SHO After SPCC but before STF update (click to enlarge)

Master SHO image After STF Update (click to enlarge)

Master SHO starless after STX

7. Process the SHO Starless Image

  • Take the image Nonlinear using the STF->HT method

  • Run SCNR Green at 0.8 to remove the green cast

  • Now we have magenta backgrounds to deal with:

    • Invert the image

    • Run SCNR Green at 0.8 again.

    • Invert the image back.

  • Now I applied a CT to darken the shadow regions and brighten the highlights - also to boost overall saturation.

  • Now I need to bring out the finer details. I chose LHE to do this.

    • Radius of 40, contrast limit of 2.0, Amount of 0.22, and an 8-bit histogram

  • Another CT to darken and boost contrast

  • Now do an MLT sharpen - see panel snapshot below for settings below.

  • Another CT to tweak things

  • Now - let's handle noise. NXT V3 is using settings from the panel snapshot below.

  • I still have too much magenta in the shadows and other areas.

    • Create a Magenta Mask using ColorMask_Mod Script

    • Blue is using Bill Blanshan’s Mask Blur Script.

    • Apply mask

    • Use CT to adjust saturation on masked areas.

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The initial nonlinear SHO Starless image (click to enlarge)

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After Inverting the SHO image. (Click to enlarge)

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Invert again. Magenta mostly gone! (click to enlarge)

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After LHE to bring out faint detail (click to enlarge)

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MLT Sharpening Panel (click to enlarge)

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Another CT adjust. (click to enlarge)

After SCNR Green at 0.8 (click to enlarge)

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Run SCNR Green at 0.8 again (click to enlarge)

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CT to Darken shadows and boost overal saturation (click to enlarge)

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Another CT to again darken and boost sats (click to enlarge)

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After MLT Sharpening (click to enlarge)

NXT Params used.

After NXT

Creating the Magenta Color Mask.

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Magenta Mask after blur operation (click to enlarge)

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Initial Magenta Mask (click to enlarge)

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CT to remove saturation with Magenta Mask in place (click to enlarge)

8. Add The Stars Back In

  • Use the ScreenStars Script to add the stars back in.

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The Final RGB Stars Image (click to enlarge)

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The Final Starless SHO image (click to enlarge)

ScreenStars Panel.

The image with Stars inserted!

9. Export the Image to Photoshop for Polishing

  • I am pretty happy with the image and ready to polish it in Photoshop.

  • Save the image as a TIFF 16-bit unsigned and move to Photoshop

  • Make final global adjustments with Clarify, Curves, and the Color Mixer - slight tweaks really

  • Run Clarifier on the bottom-left corner and top center to get better definition. Areas selected with a lasso with a 100 pixel feather.

  • Added Watermarks

  • Export Clear, Watermarked, and Web-sized jpegs.

The Final Image!

Patrick A. Cosgrove

A retired technology geek leveraging his background and skills in Imaging Systems and Computers to pursue the challenging realm of Astrophotography. This has been a fascinating journey where Art and Technology confront the beauty and scale of a universe that boggles the mind…. It’s all about capturing ancient light - those whispering photons that have traveled long and far….

https://cosgrovescosmos.com/