Introduction

What the e-CALLISTO FITS Analyzer is

The e-CALLISTO FITS Analyzer is a cross-platform desktop application for visualizing, processing and analyzing solar radio dynamic spectra recorded in FITS format by the e-CALLISTO spectrometer network, and for placing those observations in their solar and geophysical context. It runs natively on Windows, macOS and Linux (Debian and Ubuntu) and is distributed as self-contained installers, so no separate Python installation is required.

e-CALLISTO is a world-wide network of CALLISTO radio spectrometers that monitors the Sun around the clock (Benz et al. 2009). Each station records dynamic spectra — radio intensity as a function of frequency and time — in FITS files that normally span 15 minutes. A station may operate several receivers or frequency bands, each identified by a two-digit focus code. File names follow the pattern STATION_YYYYMMDD_HHMMSS_FC.fit.gz, for example Australia-ASSA_20261004_000000_63.fit.gz for focus code 63 of the Australia-ASSA station starting at 00:00:00 UT on 4 October 2026.

The application merges fragmented observations across time and frequency, removes the receiver background, mitigates radio-frequency interference (RFI), and isolates solar radio bursts with an interactive mask. Dedicated tools derive the frequency drift rate and shock parameters of Type II bursts and estimate the coronal magnetic field from band-split emission. Around this core, the software retrieves archive data from several radio instruments, displays X-ray, particle, geomagnetic and coronal mass ejection (CME) data for the same interval, analyzes solar images from space-borne observatories, models the coronal magnetic field, and reconstructs CMEs in three dimensions.

Capabilities at a glance

Table 1.1 summarizes the main modules, where they are opened, and where they are described in this guide.

Supported data

The application reads and retrieves the data types listed in Table 1.2. The archives behind each retrieval tool are listed in Appendix C.

Workflow overview

Figure 1.1 shows how the main components relate to each other. Data enter the main window from local files, the downloaders or a saved project; they are processed in the sidebar; analysis windows take the processed spectrum as input; and every stage can be saved in a project or exported. The context and imaging tools can be synchronized to the time window of the loaded spectrum.

What is new in version 3.1.0

Version 3.1.0 adds or substantially extends the following features, all of which are described in this guide:

• automatic ridge tracking in the Maximum Intensities window (Section 8.4);

• a selectable power-law time origin $t_0$ and five coronal density models with a side-by-side comparison in the Burst Analyzer (Section 8.7);

• drag-and-drop opening and lists of recent files and projects (Section 5.2);

• the Timeline panel for extending a spectrum with adjacent observations (Section 6.1) and a linear or logarithmic frequency axis (Section 6.5);

• separate background-subtraction controls that always start from the raw data (Section 6.2);

• the Burst List catalog tab and unified time $\times$ frequency combination in the downloader (Chapter 11);

• PFSS coronal-field modeling, calibration-level selection, differential-rotation compensation, circle fitting and higher-order kinematics in Solar Image Analysis (Part V);

• multi-view GCS flux-rope and shock fitting with staged refinement, movies and fitting reports (Part VI).

Citing the software

If you use the e-CALLISTO FITS Analyzer in your research, please cite Liyanage et al. (2026). The citation and a BibTeX entry can be copied from the application with the Cite this Software button (Section 4.2). The BibTeX entry is:

When you publish results that depend on archive data retrieved through the application, acknowledge the corresponding data providers as well (Appendix C).