Afterglowscreensavers

The Auroral Oval Screensaver

The Auroral Oval screensaver wraps NOAA's live OVATION aurora forecast onto a globe at the altitude the aurora actually occurs — about 100 kilometres up. It runs in the browser with nothing to install; press ESC to exit.

Live preview

Press ESC to leave fullscreen. Settings are saved in your browser only.

How the The Auroral Oval screensaver works

The saver renders with three.js on your GPU. The library is vendored into this site rather than fetched from a CDN, and loads only when a 3D screensaver actually runs.

It reads NOAA Space Weather Prediction Center's OVATION model output, which is public and needs no key.

The scene resizes with the window and releases its WebGL context when the saver stops, so shuffle mode and Multi-view can cycle 3D savers without exhausting the browser's context limit.

If WebGL is unavailable the saver says so on screen rather than showing an empty black box.

A worked example

The model publishes an aurora probability for every degree of latitude and longitude — roughly a megabyte of grid — and cells below a threshold are dropped, or the globe vanishes under a haze. What remains is the oval: not a cap over the pole but a ring offset from it, because it follows the geomagnetic field rather than the geographic axis. Colour runs from green to red with intensity, and the camera nods between the poles.

Settings & tips

Frequently asked questions

Why is the oval a ring rather than a cap?
Because it marks where field lines that stretch far out into the magnetotail return to the atmosphere. Those lines come down in a ring around the magnetic pole, so the aurora does too — and the magnetic pole is not the geographic one.
Does this mean I can see it tonight?
Only loosely. The model gives probability of aurora overhead, and seeing it also needs darkness, clear sky and no moon. It is a forecast of the phenomenon, not of your view of it.
Does this need a special browser or plugin?
No. It uses WebGL, which every current desktop and mobile browser supports. Nothing is installed and no plugin is required.
Does it cost anything or need an account?
No. Every screensaver here is free, runs in the browser and needs no sign-up.

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