# Astrophotography Stacking Guide > Source: > Published: 2026-06-20 11:45:18+00:00 # **The Complete Guide to Mobile Astrophotography Stacking** **Device:** Motorola Edge 60 Fusion | **OS:** Fedora Linux | **Software:** Siril Stacking combines multiple long exposures to reduce digital noise and reveal faint details of the Milky Way that a single phone camera shot cannot capture. This guide takes you from field capture to the final processed masterpiece. ## **PHASE 1: Capturing the Night Sky (In the Field)** ### **1. Set Up Your Gear** - **Tripod:** Mount your phone on a sturdy tripod. Any movement ruins the alignment. - **Trigger:** Use a Bluetooth remote or a 2-second delay timer so tapping the screen doesn't shake the phone. - **Intervalometer:** Use an intervalometer app (if available) to automatically trigger the shutter repeatedly. ### **2. Configure Pro Mode** Open your default camera app, switch to **Pro Mode**, and apply these exact settings for your 24mm main lens: - **Format:** RAW (DNG). *Crucial: JPEGs cannot be stacked properly.* - **Focus:** Manual, set all the way to Infinity (∞). - **Shutter Speed:** **16 seconds**. (The "500 Rule" limits this lens to ~20 seconds before stars trail; 16 seconds guarantees sharp pinpoint stars). - **ISO:** 1600 to 3200 (Start at 1600; adjust based on light pollution). - **White Balance (WB):** Manual, around 4000K (makes the sky a neutral blue/grey). ### **3. Capture "Light" Frames** - Point your camera at the target (e.g., the Milky Way core). - Take a continuous sequence of **40 to 60 photos** without moving the tripod. ### **4. Capture "Dark" Frames** - **Immediately** after your last light frame, completely cover the phone's camera lenses (use a thick cloth or lay it flat on a dark surface). No light can enter. - Keep the **exact same ISO and Shutter Speed (16s)**. - Take **15 to 20 photos**. *Purpose: Maps the thermal heat noise generated by the sensor during a 16-second exposure.* ## **PHASE 2: Capturing Calibration Frames (At Home)** ### **5. Capture "Bias" Frames** You can do this inside your house at any time. - Keep the lenses completely covered (pitch black). - Set the **ISO to the same value** used for your Lights/Darks. - Change the Shutter Speed to the **fastest possible setting** (e.g., 1/4000s or 1/8000s). - Take **20 photos**. *Purpose: Maps the instantaneous electronic read noise of the camera sensor.* ## **PHASE 3: Preparing the Data (On Fedora)** ### **6. Install Siril** Open your terminal and install Siril from the official repositories: sudo dnf install siril ### **7. Organize Your Folders** Siril automated scripts require a strict, specific folder structure to work. - Create a main project folder (e.g., Desktop/MilkyWay). - Inside it, create three sub-folders exactly named (all lowercase, plural): - lights (Put your 40-60 star DNGs here) - darks (Put your 16s dark DNGs here) - biases (Put your fast-shutter bias DNGs here) ### **8. Add the Missing Script** - Open Siril. - Click the **"Scripts"** menu at the top. - Click **"Get Scripts"**. - Find and install the script named **OSC_Preprocessing_WithoutFlat** (OSC = One Shot Color). ## **PHASE 4: Stacking in Siril** ### **9. Run the Automation** - Click the **"Home" icon** (Change working directory) in the top left of Siril. Select your main MilkyWay folder. - Go to **Scripts** -> **Siril Script Files** -> **OSC_Preprocessing_WithoutFlat.ssf**. - Let the script run. It will calibrate, align, and stack your images. This takes a few minutes. - Wait for the green text in the console: *"Execution of the script is successful."* ## **PHASE 5: Post-Processing the Masterpiece** ### **10. Reveal the Data** - Click the **Open** button (top left) and open result.fit from your MilkyWay folder. - The screen will be dark. Look at the bottom-center of the Siril window. Change the dropdown from **Linear** to **AutoStretch**. Your stars will appear! ### **11. Crop the Artifacts** Because the Earth rotated, Siril had to rotate your images to align the stars, leaving jagged black borders. - Click and drag a box over the good part of your image, excluding all black edges. - Right-click inside the box and select **Crop**. ### **12. Fix the Colors (Remove the Green)** Stacking RAWs makes the image very green. Let's neutralize it. - Draw a small selection box over a **dark, empty part of the sky** (avoid bright stars or the Milky Way band). - Go to **Image Processing** (top menu) -> **Color Calibration** -> **Color Calibration**. - In the "Background Reference" section, click **Use current selection**, then click **Background Neutralization**. The green cast will vanish! Close the window. - Go to **Image Processing** -> **Remove Green Noise**. Click **Apply** and close. ### **13. Permanently Stretch the Image** AutoStretch is just a preview. If you save now, it will be pitch black. - Change the bottom-center dropdown from **AutoStretch** back to **Linear**. (The image goes dark again). - Go to **Image Processing** -> **Histogram Transformation**. - Click the **Gear Icon** in that window to apply the AutoStretch settings permanently. - Click **Apply** and close the window. ### **14. Export and Share!** - Click the **Save As** icon (the arrow pointing down to a hard drive near the top right). - Change the file type extension from .fit to **JPEG** or **TIFF**. - Name your file (e.g., Final_MilkyWay.jpg) and click **Save**.