# AstroImageJ: Image Processing and Photometric Extraction for Ultra-Precise Astronomical Light Curves (Expanded Edition)

## TL;DR

AstroImageJ is a user-friendly, cross-platform software tool that enhances astronomical image processing and photometry, enabling precise light curve analysis for exoplanet research and other applications.

## Contribution

It introduces an astronomy-specific, GUI-based extension of ImageJ with tools for ultra-precise photometry, calibration, and analysis, tailored for time-series astronomical data.

## Key findings

- Supports standard FITS and image formats with WCS awareness
- Automates plate solving via astrometry.net integration
- Facilitates quick processing and plotting for educational and research use

## Abstract

ImageJ is a graphical user interface (GUI) driven, public domain, Java-based, software package for general image processing traditionally used mainly in life sciences fields. The image processing capabilities of ImageJ are useful and extendable to other scientific fields. Here we present AstroImageJ (AIJ), which provides an astronomy specific image display environment and tools for astronomy specific image calibration and data reduction. Although AIJ maintains the general purpose image processing capabilities of ImageJ, AIJ is streamlined for time-series differential photometry, light curve detrending and fitting, and light curve plotting, especially for applications requiring ultra-precise light curves (e.g., exoplanet transits). AIJ reads and writes standard FITS files, as well as other common image formats, provides FITS header viewing and editing, and is World Coordinate System (WCS) aware, including an automated interface to the astrometry.net web portal for plate solving images. AIJ provides research grade image calibration and analysis tools with a GUI driven approach, and easily installed cross-platform compatibility. It enables new users, even at the level of undergraduate student, high school student, or amateur astronomer, to quickly start processing, modeling, and plotting astronomical image data with one tightly integrated software package.