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SolarConflux

One Sun. Several spacecraft. When do their viewpoints align?

I built SolarConflux to turn spacecraft trajectories into candidate observation windows. It screens useful geometries for coordinated solar and heliospheric observations, then keeps the dates and assumptions together for follow-up analysis.

My role
Designer & developer
Project context
ESA · 2023–2025
Today
Open-source Python & web explorer
Open the explorerView on GitHub
Conceptual paper illustration of the Sun surrounded by three spacecraft at different viewpoints

The question

A shared view starts with geometry.

Spacecraft sample the heliosphere from different places. Their relative positions help determine which measurements may be useful together, whether for comparing viewpoints or investigating how solar-wind structures evolve with distance.

Searching many trajectories by hand quickly becomes cumbersome. SolarConflux asks a simpler first question: when do the selected bodies satisfy a geometry worth investigating?

From positions to possibilities

Find the geometry first. Interpret it with the observations.

An alignment is a starting point for analysis. It helps shortlist dates; measurements and physical models are needed to establish what the spacecraft actually share.

Trajectories → candidate windowsConceptual illustration

Approach

From ephemerides to a shortlist.

  1. Retrieve trajectoriesChoose spacecraft, planets, dates and sampling. Express the ephemerides in a common Sun-centred frame.
  2. Compare geometriesScreen circular longitude separations or ballistic Parker footpoints, with an optional group latitude filter.
  3. Find windowsGroup successive matching samples into candidate intervals. Their boundaries follow the sampling cadence.
  4. Keep the contextExport the windows, settings and data provenance alongside plots for further investigation.

Different geometries, different questions.

  • Cone

    When are observers close in longitude to an anchor body?

  • Opposition

    When are two observers about 180° apart in longitude?

  • Quadrature

    When are two observers about 90° apart in longitude?

  • Custom angle

    When does their separation approach a chosen angle?

  • Parker spiral

    When do approximate ballistic source longitudes agree?

  • Cone + Parker

    When do the sector and Parker criteria both hold?

Diagrams are conceptual. The geometric modes compare longitude; latitude can be filtered separately. Groups share an anchor body; not every pair in a group necessarily meets the criterion. Parker modes use a simplified ballistic approximation.

A worked example · January 2025

What does a candidate window look like?

The bundled example contains Earth, Solar Orbiter and BepiColombo. Here, a 15° cone criterion with a 10° latitude-span limit selects one interval for Earth and Solar Orbiter. BepiColombo is shown for context and does not belong to that matched pair.

Matching pair
Earth + Solar Orbiter
Candidate interval · UTC
1 Jan 00:00 → 7 Jan 18:00
Sample spacing
6 hours
Sampled duration
162 hours

Where the observers are

Sun-centred positions on 1 January 2025, with a 15-degree longitude sector containing Earth and Solar Orbiter; BepiColombo lies outside itSun-centred positions on 1 January 2025, with a 15-degree longitude sector containing Earth and Solar Orbiter; BepiColombo lies outside it
Markers show 1 January, 00:00 UTC. Lines join the retrieved samples through 15 January. Heliocentric inertial coordinates, projected into the solar equatorial plane; distances in AU. Select the figure to open it at full size.

When the criterion holds

Earth–Solar Orbiter circular longitude separation crosses the 15-degree criterion after 7 January at 18:00 UTC; 28 samples meet the criterionEarth–Solar Orbiter circular longitude separation crosses the 15-degree criterion after 7 January at 18:00 UTC; 28 samples meet the criterion
The shaded interval spans the first to last matching sample. All 28 matching samples also meet the latitude-span limit. The next sample, on 8 January at 00:00 UTC, lies outside the cone. Select the figure to open it at full size.

These are sampled boundaries, not exact entry and exit times. The interval begins at the first requested sample, so an earlier start is not inferred. The plots illustrate a geometry, not confirmed shared plasma or magnetic connectivity.

Inspect the exampleSource ephemeridesSample values · CSVProvenance · JSON

The tool today

Explore, inspect, keep the context.

The web explorer makes the workflow visible: configure observation periods, follow trajectories, inspect matching intervals and export the results. Saved runs can be reopened in History on the same browser.

The bundled example and imported trajectories can be screened without live retrieval. Live ephemerides are retrieved through a separate service; availability depends on the selected bodies, dates and data source.

Try the January example
Tools
Python · SunPy · Astropy · Astroquery · NumPy · Matplotlib
Data
JPL Horizons · SPICE kernels where available · imported trajectories
Outputs
Candidate-window CSVs · run metadata · plots · browser run backups
Method notesScientific assumptionsParker convention
Python usage & original quick-look figures

Use the Python package

pip install git+https://github.com/EmmaVellard/SolarConflux.git

The command-line workflow exposes the same screening modes and exports CSVs, run metadata and optional polar plots.

Installation & examples

Earlier output figures

The original cone and Parker quick-look plots remain available. The figures above use the documented January dataset so their inputs and styling can be reproduced.

Original cone plotsOriginal Parker plots