Processing Tools Used

• GraXpert - https://www.graxpert.com/

• Siril - https://siril.org/

• AstroSharp - https://github.com/deepskydetail/AstroSharp

• Photoshop

• Lightroom

Useful Videos

• Siril How toos - https://www.youtube.com/@DeepSpaceAstro

Hubble Palette

• https://www.youtube.com/watch?v=wDtTIqqE-mk

Stack the fit files in Siril first using the Seestar Script

Image Processing Steps:

1. Auto Stretch:

   • Apply the auto stretch to the image.

2. Crop the Image:

   • Crop the image to remove noise and artifacts.

3. Background Extraction:

   • Click on areas of dark sky to perform background extraction. Adjust dither settings if necessary.

4. Remove Green Noise:

   • Eliminate any green noise present in the image.

5. Photometric Color Calibration:

   • Search for the object in the calibration tool, then apply the calibration.

5a . Go to GraXpert and denoise.

6. Return to Linear Mode:

   • Switch the image back to linear mode.

7. Generalized Hyperbolic Stretch Transformation (GHST):

   • Set the zoom to 100%.

   • Click on the far left middle of the curve and adjust the stretch factor until you achieve a satisfactory result, aiming for a value around 0.00050.

   • Reset the zoom to 1x.

   • Repeat until you like the image

8. Histogram Stretch:

   • Perform a histogram stretch to eliminate clipping, iterating as needed.

9. Color Saturation:

   • Adjust the color saturation as desired, repeating as many times as necessary.

10. Star Processing:

    • Remove stars from the image.

    • After processing, recompose the stars and upsample by a factor of 2.

    • Experiment with the stretch settings, using a value of 0.5 and 0.5 for both.

11. Save as TIFF:

    • Save the processed image as a TIFF file.

    • Apply astro sharpening using PSF and other models, setting the aggressiveness to 0.5. Play with sttings

Processing the Pin Wheel Galaxy:   https://www.youtube.com/watch?v=h-8wzg5ohy4