1. Install DSS by downloading the installer appropriate for your OS from this page: https://github.com/deepskystacker/DSS/releases/tag/6.1.0 (“Assets” at the bottom of the page)
2. Download some raw data from here:
3. Open DSS app ( not that not the Live app).
4. Click on Open picture files … on the top left corner of the sidebar. Select the downloaded FITS photos. These are your light frames.
5. Click on dark, flat, and offset/bias consecutively to add the dark, flat, and bias frames. These are your calibration files.
6. Make sure that all the images in all the tabs are selected in the bottom box. If not, click the Check all button in the second box on the left sidebar.
7. Click on Register checked pictures…

Uncheck Stack after registering

1. Click on the advanced tab, click on the check the number of detected stars button. See if the number is more than 60 or not. If not, lower the detection threshold, and click on detect again. 60-300 stars is a good number.

• Go to: https://siril.org/download/
• Download the installer for your operating system.
• Install:
  • Windows → run the .exe
  • macOS → open .dmg and move Siril to Applications
  • Linux → use AppImage or package manager

• Download StarNet++ from the provided link.
• Extract the folder to a known location (example: C:/Siril/Starnet2/).

• Download the provided script.
• Place it in your Siril scripts directory:
  • Windows → C:\Users\<user>\AppData\Local\Siril\scripts\
  • macOS → ~/Library/Application Support/siril/scripts/
  • Linux → ~/.config/siril/scripts/

• Download the dataset from the provided Drive link.
• Extract everything into a working directory.

The data is already calibrated. Only light frames are provided.

Create the following folders:

• L/
• R/
• G/
• B/
• HA/

Move each filter’s images into its respective folder.

• Open Siril.
• Click the Home (house) icon → top-left corner.
• Navigate to the parent directory that contains the subfolders: L, R, G, B, HA.
• Select that directory.

• Go to Scripts tab.
• Select the installed script.
• Siril begins checking and preparing images.
• Preview window appears.

To change preview mode:

• Bottom bar → switch Linear ⇄ AutoStretch.

• Go to Process → Background Extraction.
• Place sample points on dark, empty background areas.
• Ensure no stars, nebula, or bright zones under the points.
• Click Apply (Extract Background).

• Go to Analysis → Astrometry → Plate Solver.
• Enter:
  • Focal length
  • Pixel size
  • Camera sensor information
• These values are visible under Image Information.
• Click Solve.

• Go to Color → Photometric Color Calibration.
• If Gaia server is down → download Gaia catalog locally from Siril’s database manager.
• Run SPCC.

• Go to Color → Linear Photometric Color Calibration.
• Load local Gaia index file.
• Run LPCC.

Stretch *before* star removal for best results.

• Go to Image Processing → Histogram Transformation.
• Use AutoStretch or adjust:
  • Black point
  • Mid-level
  • White point
• Apply the stretch.

• Go to Process → Star Removal → StarNet++.
• Set the StarNet++ executable path if prompted.
• Enable:
  • “Create starless image”
  • “Create star mask”
• Run StarNet++.

Output:

• One starless image
• One stars-only image

• Go to Color → Saturation.
• Increase moderately.

• Go to Image Processing → Curves.
• Adjust luminance/RGB to preference.

• Go to Image Processing → Pixel Math.
• Combine:

``starless + stars``

• Apply to produce the final image.

• Go to File → Save As.
• Export as TIFF, PNG, or FITS.