Reference
Where the Sun, Moon and planets are for a date, in two scales, with the camera maths
import { … } from "@johnmorrisdotca/wakusei-planets/space";Exports
| Name | Kind | What it is |
|---|---|---|
AU_IN_EARTH_RADII | constant | Earth radii in one astronomical unit. |
blend | function | A frame between two others, t from 0 to 1. |
compress | function | The same direction at a compressed distance from the Earth: the Moon is 10 Earth radii away, and a body k times further than the Moon is k^0.25 times as far here. |
createTrack | function | Answers for any moment from two real ones: at(ms) works out a frame only when ms leaves the span the last two answers cover, and then looks stepMs ahead, so playing time at a steady rate costs one pair of lookups every stepMs and every draw in between is arithmetic. |
EARTH_RADIUS_KM | constant | The Earth's equatorial radius in kilometres (IAU), the unit of the scene's distances. |
frameAt | function | The state of the sky at ms: the Sun, the Moon and eight planets as seen from the Earth's centre, worked out by this package's own models in a fraction of a millisecond. |
groundDirection | function | The unit direction, in the scene's axes, of a longitude and latitude on the Earth as the stars see it at ms: the camera fixed to the stars looks at the same place on the ground only at that moment, and the Earth turns away under it as time runs. |
MOON_COMPRESSED | constant | The Moon's distance in a compressed view, in Earth radii (the true one is about 60). |
placeAround | function | A place helio astronomical units from the Sun (a planet, or a point on its orbit), round the Sun at sun. |
placeMoon | function | The Moon, from the Earth's centre. |
placeSun | function | The Sun, from the Earth's centre: in a compressed view always 44 Earth radii away, in its real direction. |
planetOrbit | function | The path a planet takes round the Sun, as count + 1 points round one trip from where the planet is at ms, from the Sun, in astronomical units and the scene's axes. |
radiusIn | function | A body's radius in Earth radii: the real one, or one large enough to see in a compressed view. |
RIDE_FOV | constant | The field of view, in degrees, of a camera riding along at zoom 1. |
RideInput | type | What ridePose is asked: the camera's place from the centre of the body it goes round and its way of travel (any length), that body's radius in the unit of the place, where it looks, and the shared controls' yaw, tilt and zoom. |
RideLook | type | Where a riding camera looks: down straight at the centre of the body it goes round (the ground goes by under the camera), or horizon tipped forward along the way it is going until the horizon is a little above the middle of the view. |
ridePose | function | The camera of a body-borne view: at position, looking at the body it goes round (a Moon over the Earth, a moon over Jupiter, a spacecraft over Mars: any centre, by radius), with the way it is going at the top of the picture. |
RidePose | type | The camera ridePose works out: where it is, which way it looks, which way is up in the picture, its field of view in degrees, and how big the body looks from there (its angular radius in degrees). |
ScaleMode | type | The scale the space view is drawn in: compressed squeezes the distances so the Moon, the Sun and Neptune fit one view, and true keeps the real ones. |
SPACE_PLANETS | constant | The planets the space view places, nearest the Sun first (the Earth is the middle of the view). |
SpaceFrame | type | Where everything is at one moment: positions in astronomical units from the Earth's centre, in J2000 equatorial axes with y north. |
SpacePlanet | type | One of the planets in SPACE_PLANETS. |
SpaceVec3 | type | A position or direction as [x, y, z] in the scene's axes: J2000 equatorial, x to the vernal equinox, y north. |
SUN_COMPRESSED | constant | The Sun's distance from the Earth in a compressed view, in Earth radii (the true one is about 23,500). |
truePosition | function | A place in astronomical units from the Earth's centre, at true distance, in Earth radii. |