First eclipse image

Three commands take a fresh solution to a synthetic eclipse render. They follow the pipeline's natural cost seam: the Q⊥ volume is expensive and viewpoint-independent, so it is built once; a render off that volume is cheap, so it is done for as many cameras as wanted.

This walkthrough uses the example data, data/coconut_corona.CFmesh.xz.

1. Inspect

qorona info data/coconut_corona.CFmesh.xz --timestamp 2025-10-09T18:19:52

info reads the solution and reports what Qorona sees: model, mesh, variables, boundaries. Nothing is rendered; use it to confirm a file is understood before spending minutes on a build.

2. Build the Q⊥ volume

qorona build data/coconut_corona.CFmesh.xz -o data/coconut_corona.qor \
    --timestamp 2025-10-09T18:19:52 --frame carrington --outer-radius 8

The minutes-scale stage: trace the field, assemble Q⊥, and cache it to coconut_corona.qor. --quality fast gives a minute-scale preview (timings on the GPU page); --quality and --outer-radius are covered on the Q⊥ volume page. --timestamp and --frame record what the file does not carry: the observation time and the heliographic frame of the solution's longitudes, carrington here (stonyhurst for a run driven by a magnetogram rotated to HEEQ). Both are optional and both are baked into the volume: the time drives the on-image Carrington-rotation stamp, and together they let a render point the camera at a real observer instead of typed angles (step 3).

3. Render

qorona render data/coconut_corona.qor -o data/eclipse.png --fov 8 --longitude 317 --latitude 6.2

Seconds per viewpoint, any number of viewpoints off the one volume. --fov is the field of view (full width) in solar radii; --longitude and --latitude set the sub-observer heliographic point, --roll the camera roll. With the time and frame baked into the volume, the camera can also take a real observer's viewpoint on that date, no angles typed:

qorona render data/coconut_corona.qor -o data/earth.png --fov 8 --observer earth

Camera and viewpoint covers both ways of pointing the camera.

The figure below is exactly this render:

What you get

Every command ends with a summary of its parameters and metrics, and the PNG carries a corner stamp (Carrington rotation, timestamp, sub-observer angles, roll, FOV), so any image can be traced back to what produced it.

qorona run chains the whole pipeline in one shot; --save-volume keeps the intermediate so later renders are instant:

qorona run data/coconut_corona.CFmesh.xz -o data/eclipse.png \
    --timestamp 2025-10-09T18:19:52 --frame carrington \
    --fov 8 --longitude 317 --save-volume data/coconut_corona.qor

Next

One page per product: squashing-factor render, polarity view, white-light imaging, Q-maps, field lines.