# SkyAtmosphere

> Talos 0.7 · Since 0.6; changed in 0.7

## Fields

| Field | Type | Required | Default | Allowed values | Description |
|---|---|---|---|---|---|
| `preset` | `AtmospherePreset` | no |  | `earth-clear`, `hazy`, `polluted`, `stylised` | Named atmosphere: earth-clear (the default: clean air), hazy (three times the aerosols), polluted (dense absorbing aerosols, a brown low-contrast sky) or stylised (bluer and more saturated than Earth). |
| `planetRadiusKm` | `number` | no |  |  | Radius of the planet, kilometres, within 100..100000. Default 6360 (Earth). A small planet curves its horizon sooner, which a large world notices. |
| `groundAlbedo` | `number` | no | `0` |  | How much light the planet's surface reflects, within 0..1. Default 0.3. It lights the sky from below and is the ground seen past the level's edge. |
| `haze` | `number` | no | `1` |  | Scale on the preset's aerosols (Mie scattering), within 0..10. Default 1; 0 is air with no aerosols, 3 a hazy day. |
| `visibilityKm` | `number` | no |  |  | Meteorological visibility, kilometres, within 0.1..1000: how far a dark object can be seen against the horizon sky. It sets the air's total extinction at ground level (Koschmieder: 3.912 / visibility per km, of which Rayleigh scattering is the molecular share and the aerosols the rest) and overrides `haze`. Absent keeps the preset's aerosols (earth-clear is about 217 km); 50 is a clear day, 25 a typical one, 10 a hazy one, 1 fog. |
| `aerialScale` | `number` | no |  |  | Artistic scale on the aerial perspective only, within 0..100: the air between the camera and a surface is drawn this many times as dense, as if every distance were this many times longer, so a world a few kilometres across can show the layered, blue-shifted depth of a real range tens of kilometres deep. Default 1 (physical); 0 is no aerial perspective. The sky itself, the sun's colour and the ambient light are unchanged. Combine with `visibilityKm`: 10 at 90 km visibility hazes a 4 km valley about as 9 km visibility would, without greying the sky. |

## See also

- `AtmospherePreset`