WBPP Guide

Introduction

Weighted Batch Preprocessing (WBPP) is PixInsight’s all-in-one script that calibrates, registers, and integrates your subframes into a clean master light.

It may look intimidating at first, but once you understand what to enable, it becomes one of the most powerful tools in your workflow.

🌌 Why WBPP Matters

WBPP automates calibration, alignment, and stacking — the three pillars of deep sky imaging.

Done properly, it preserves faint detail, reduces noise, and ensures accurate colour.

Preparation is everything. Good calibration is half the battle.

1️⃣ Opening WBPP

Go to:

📸 WBPP main window

2️⃣ Adding Your Frames

Lights

• Add all light frames
• Group exposures logically
• Exposure tolerance: ~20%
• ✔️ CFA Images (for OSC/DSLR)

Darks

• Match exposure, gain, temperature
• Optimise Darks: OFF (unless mismatched)

Flats

• Match filters and setup
• Include flat-darks or bias

Bias

• Use 50–100 frames or master bias

3️⃣ Calibration Panel

• ✔️ Linear Defects Correction: ON
• ✔️ Subframe Weighting: PSF SNR
• ✔️ Image Registration: ON
• ✔️ Local Normalisation: ON
• ✔️ Image Integration: ON
• ✔️ Astrometric Solution: ON

4️⃣ Post-Calibration Panel

• ✔️ Debayer (OSC/DSLR)
• ✔️ Drizzle: OFF (unless undersampled)
• ✔️ Fast Integration: OFF

5️⃣ Pipeline Panel

• ✔️ All steps active
• ✔️ Generate Rejection Maps
• ✔️ Preserve White Balance: OFF
• ✔️ Detect Masters from Path

6️⃣ Integration Panel

• ✔️ Average combination
• ✔️ Winsorized Sigma Clipping
• ✔️ Large-scale rejection ON
• ✔️ Sigma: 4.0 / 3.0

7️⃣ Running WBPP

• Set output folder
• Run diagnostics
• Click Run

✅ Minimum Setup

• Lights + Darks only
• Optimise Darks if no bias
• Expect reduced quality

🚀 Advanced Setup

• Use full calibration set
• Enable Local Normalisation
• Use Drizzle if undersampled

🛠️ Troubleshooting

Noisy master

• Add more subs (noise ∝ √N)
• Check calibration matches

Blurry stars

• Registration issue
• Remove poor subs

Flats not working

• Check optical match
• Include bias or flat-darks

WBPP crash

• Check logs
• Verify settings

📌 Key Takeaways

• Calibration is everything
• Always inspect subs first
• Darks = minimum, flats + bias = better
• Applies to all stacking software