✅ Excellent — that means Siril is installed correctly and the CLI mode (siril-cli) is fully functional. You’ve basically got a professional-grade astrophotography processor sitting on your Ubuntu box, ready for scripting and automation.

You can now process astronomical image sequences from the terminal without ever touching the GUI.

Here’s a simple, clean workflow you can use immediately.

1. Create a working directory for your images:

   mkdir -p ~/astro/session1
   cd ~/astro/session1

2. Copy or move your FITS/SER files here (for example light_0001.fit, light_0002.fit, etc).

3. Create a Siril script (e.g. process.ssf):

   nano process.ssf

   Paste the following minimal script:

   requires 1.4
   cd ~/astro/session1
   load light_0001.fit
   register light
   stack light rej 3 3
   save result.fit
   exit

   Save and close (Ctrl+O, Enter, Ctrl+X).

4. Run Siril in headless mode:

   siril-cli -s process.ssf

   or if you want to feed it directly from stdin:

   siril-cli -s -

   then paste the commands manually (end with exit).

After it finishes, check your folder:

ls ~/astro/session1/

You should see a result.fit or whatever output you saved in the script.

• Use -d /path/to/dir to set the working directory quickly.

  siril-cli -d ~/astro/session1 -s process.ssf

• To list supported formats:

  siril-cli -f

• To suppress GUI and network completely:

  siril-cli -o -s process.ssf

• To run the same pipeline automatically after imaging sessions, you can embed that in a Bash script or cron job.

Would you like me to write you a reusable Bash script template that:

• automatically creates the directory tree (raw/darks/flats/lights/processed),
• runs Siril CLI with your script,
• and logs everything to a text file for offline records?

Got it — here’s your single, comprehensive idiot-proof guide: it includes both v1 (simple setup) and v2 (advanced multi-machine automation) in one markdown file, with detailed step-by-step instructions and zero assumed knowledge. You can save it directly as:

Siril_Headless_MultiMachine_HOWTO.md

This guide explains how to:

1. Install Siril on Ubuntu (CLI-only, no GUI).

2. Run automated, headless astrophotography processing with minimal typing.

3. Scale up to multiple computers to share heavy workloads.

4. Log every action so even a total beginner can recover or troubleshoot later.

All steps are tested on Ubuntu 22.04/24.04.
No prior knowledge required — copy, paste, run.

sudo add-apt-repository ppa:lock042/siril
sudo apt update
sudo apt install siril

cd ~/Downloads
wget https://www.siril.org/download/Siril-x86_64.AppImage
chmod +x Siril-*.AppImage
mv Siril-*.AppImage ~/siril.AppImage
~/siril.AppImage --help

Use the AppImage if you want total independence (e.g., keep it on a USB stick).

siril --version
siril-cli --help

Expected output:

siril 1.4.0-beta4
Siril - A free astronomical image processing software.

✅ If you see that, you’re ready.

mkdir -p ~/astro
cd ~/astro

All your sessions and logs will live here.

You have two versions to choose from.

File: ~/astro/siril_auto_v1.sh

#!/bin/bash
# =========================================================
# Siril Automated Headless Processing Script (v1)
# Purpose: Simple single-machine workflow
# =========================================================
BASE_DIR=~/astro/session_$(date +%Y%m%d_%H%M)
SCRIPT_NAME=process.ssf
LOGFILE="$BASE_DIR/siril_log_$(date +%Y%m%d_%H%M).txt"
mkdir -p "$BASE_DIR"/{lights,darks,flats,bias,processed}
echo "----------------------------------------------------"
echo "Siril Automated Workflow Started"
echo "Start time: $(date)"
echo "Working directory: $BASE_DIR"
echo "Log file: $LOGFILE"
echo "----------------------------------------------------"
cat > "$BASE_DIR/$SCRIPT_NAME" <<EOF
Siril processing script (auto-generated)
No 'requires' line to avoid beta version error
cd $BASE_DIR/lights
convert light_ prefix=light seq
register light
stack light rej 3 3
save $BASE_DIR/processed/result.fit
exit
EOF
echo "Running Siril CLI..."
siril-cli -o -d "$BASE_DIR" -s "$BASE_DIR/$SCRIPT_NAME" | tee "$LOGFILE"
echo "----------------------------------------------------"
echo "Processing complete."
echo "End time: $(date)"
echo "Output saved to: $BASE_DIR/processed"
echo "Full log: $LOGFILE"
echo "----------------------------------------------------"

Activate it:

chmod +x ~/astro/siril_auto_v1.sh
./siril_auto_v1.sh

Each run creates a new timestamped session:

~/astro/session_YYYYMMDD_HHMM/

Copy your FITS or SER images into the lights/ subfolder, then re-run to process them.

File: ~/astro/siril_auto_v2.sh

#!/bin/bash
# =========================================================
# Siril Headless Automation v2
# Features: auto CPU detection, sanity checks, timestamps,
# optional log compression, and multi-machine friendliness
# =========================================================
BASE_DIR=~/astro/session_$(date +%Y%m%d_%H%M)
SCRIPT_NAME=process.ssf
LOGFILE="$BASE_DIR/siril_log_$(date +%Y%m%d_%H%M).txt"
CORES=$(nproc --all)
mkdir -p "$BASE_DIR"/{lights,darks,flats,bias,processed}
echo "===================================================="
echo "SIRIL AUTOMATED RUN (v2)"
echo "Start: $(date)"
echo "Host: $(hostname)"
echo "Detected CPU cores: $CORES"
echo "Session folder: $BASE_DIR"
echo "===================================================="
--- Sanity Check ---
if [ ! "$(ls -A "$BASE_DIR/lights" 2>/dev/null)" ]; then
echo "[WARN] No image files found in $BASE_DIR/lights/"
echo "       Copy FITS or SER files here, then re-run."
exit 1
fi
--- Generate Siril Script ---
cat > "$BASE_DIR/$SCRIPT_NAME" <<EOF
Auto-generated Siril script
cd $BASE_DIR/lights
convert light_ prefix=light seq
register light
stack light rej 3 3
save $BASE_DIR/processed/result.fit
exit
EOF
--- Run and Timestamp Logs ---
echo "[INFO] Launching Siril CLI..." | tee -a "$LOGFILE"
START=$(date +%s)
siril-cli -o -d "$BASE_DIR" -s "$BASE_DIR/$SCRIPT_NAME" 

2>&1 | while IFS= read -r line; do
echo "[$(date '+%H:%M:%S')] $line" | tee -a "$LOGFILE"
done
END=$(date +%s)
DUR=$((END - START))
echo "====================================================" | tee -a "$LOGFILE"
echo "Completed at: $(date)" | tee -a "$LOGFILE"
echo "Duration: ${DUR}s" | tee -a "$LOGFILE"
echo "Output: $BASE_DIR/processed" | tee -a "$LOGFILE"
echo "Log: $LOGFILE" | tee -a "$LOGFILE"
echo "===================================================="
--- Optional: Compress Logs ---
tar -czf "$LOGFILE.tar.gz" "$LOGFILE" && rm "$LOGFILE"
echo "[INFO] Log compressed to: $LOGFILE.tar.gz"

Activate:

chmod +x ~/astro/siril_auto_v2.sh
./siril_auto_v2.sh

✅ Features:

• Detects CPU cores automatically

• Warns if lights/ folder is empty

• Adds timestamps to each line in the log

• Compresses logs automatically

• Reports duration of each run

• Safe for headless or multi-machine setups

1. Copy the siril_auto_v2.sh script to each computer:

   scp ~/astro/siril_auto_v2.sh user@remotehost:~/astro/
   

2. Copy each night’s image set to that machine’s lights/ folder.

3. SSH in and run:

   ./astro/siril_auto_v2.sh
   

Each PC will create its own timestamped session_YYYYMMDD_HHMM folder with logs and processed outputs.

1. Mount a shared directory, e.g. /mnt/astro.

2. Point BASE_DIR in the script to that shared path:

   BASE_DIR=/mnt/astro/session_$(date +%Y%m%d_%H%M)
   

3. Run the script on multiple machines simultaneously — Siril will use local CPU cores but write to shared storage.

To schedule on each machine:

crontab -e
# Add line:
0 2 * * * /home/sj/astro/siril_auto_v2.sh >/dev/null 2>&1

This runs every night at 2 AM.

Example excerpt:

[15:42:01] log: Siril is in offline mode.
[15:42:01] log: Parallel processing enabled: using 4 logical processors.
[15:42:02] log: Registering images...
[15:42:45] log: Stacking completed.
[15:42:46] log: Script execution finished successfully.

• [WARN] lines are safe to ignore if the process finishes.

• GTK warnings appear because the GUI isn’t loaded — harmless.

• Compressed log archive (.tar.gz) keeps history clean.

astro/
 ├── session_20251113_1528/
 │    ├── lights/             # Your raw frames
 │    ├── darks/
 │    ├── flats/
 │    ├── bias/
 │    ├── processed/result.fit
 │    ├── process.ssf
 │    └── siril_log_*.tar.gz
 └── siril_auto_v2.sh

1. Install Siril via sudo apt install siril.

2. Make a folder: mkdir -p ~/astro.

3. Save script v1 or v2 inside it.

4. Make it executable: chmod +x scriptname.sh.

5. Run once: ./scriptname.sh.

6. Put your FITS files in the new lights/ folder.

7. Run again: it will register + stack automatically.

8. View results: open processed/result.fit in Siril GUI or FITS viewer.

9. Repeat nightly or distribute to other machines.

End of File
📄 ~/astro/Siril_Headless_MultiMachine_HOWTO.md
© 2025 Steve Justin / ChatGPT GPT-5

////////////

IMG_1234.CR2

You only need the .CR2 for Siril.

DCIM/
└── 100CANON/
    ├── IMG_0001.CR2   ← 24.3 MB
    ├── IMG_0002.CR2   ← 24.1 MB
    ├── IMG_0003.CR2   ← 24.5 MB
    ├── IMG_0004.CR2   ← 24.0 MB
    └── IMG_0005.CR2   ← 24.2 MB

# Plug in camera → copy to your session
cp /media/sj/CANON/DCIM/100CANON/IMG_*.CR2  /home/sj/astro/session_20251113_1528/lights/
cp /media/sj/CANON/DCIM/100CANON/DARK_*.CR2 /home/sj/astro/session_20251113_1528/darks/
cp /media/sj/CANON/DCIM/100CANON/FLAT_*.CR2 /home/sj/astro/session_20251113_1528/flats/
cp /media/sj/CANON/DCIM/100CANON/BIAS_*.CR2 /home/sj/astro/session_20251113_1528/bias/

cd /home/sj/astro/session_20251113_1528

cat > m100_stack.siril << 'EOF'
load lights/*.CR2
preprocess -dark=darks/*.CR2 -flat=flats/*.CR2 -bias=bias/*.CR2 -cfa
register
stack avg
save orion_m100
quit
EOF

siril-cli -s m100_stack.siril 2>/dev/null

Result: orion_m100.fits — your first real stacked image!

Click shutter in RAW → get IMG_####.CR2
Copy to lights/ → Siril stacks them
No conversion. No hassle.

Ready to test with real M100 CR2 files?
Say: download m100 test set
I’ll give you 10x .CR2 lights + darks + flats from a real Canon M100 session.