FITS Calibrator

A Python/Tkinter desktop application for automated FITS image calibration and plate-solving for astrophotography workflows.

Features

• Calibrate Science Frames — applies bias subtraction, dark subtraction (exposure-scaled), and flat correction to raw FITS images
• Create Master Cal Files — build master bias, dark, and flat frames from sets of calibration frames
• Plate-solving via ASTAP — automatically solves WCS coordinates for each calibrated frame
• Monitor mode — watches an input directory and processes new FITS files automatically as they arrive, with optional scheduled start/stop times
• Process Existing Files — one-shot batch calibration/plate-solving of all FITS files currently in the input directory
• Flexible calibration inputs — use raw calibration frames or pre-built master files
• Live status counters — tracks calibrated, plate-solved, and failed file counts per session
• Settings persistence — all paths and options saved automatically between sessions

Requirements

• Windows 10/11
• Python 3.10+ with the following packages:
  • astropy
  • numpy
  • watchdog
• ASTAP (optional, required for plate-solving)

Installation

pip install astropy numpy watchdog
python fits_solver.py

Or use the included FITS Calibrator.bat launcher.

Building the Executable

Requires PyInstaller:

pip install pyinstaller
pyinstaller "FITS Calibrator 2.2.0.spec"

The onedir build will be created in the dist/ folder.

Usage

1. Set the Input Directory (folder containing your raw FITS light frames).
2. Set the Output Directory (calibrated files are written to a Calibrated/ subdirectory inside this folder).
3. Under Calibration, enable calibration and select your dark, flat, and/or bias files (or master files).
4. Under Platesolve, enable plate-solving and point to your ASTAP executable.
5. Use Start Monitoring to watch for new files, or Process Existing Files to batch-process what's already in the input directory.

Pipeline

Input Dir → Calibrated/image_CAL.fits → Calibrated/image_CAL_WCS.fits

Version History

Version	Date	Notes
2.2.0	2026-03-28	Added "Use master files" toggle; UI sizing improvements
2.1.x	2026	Plate-solve integration, schedule stop
2.0.0	2026	Full rewrite with Monitor + batch modes

License

MIT License — © Art Trail 2026. See LICENSE for details.