> For the complete documentation index, see [llms.txt](https://docs.radiantdrift.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.radiantdrift.com/reference/definitions.md).

# Definitions

Response fields are defined here.

| Parameter                      | Units               | Description                                                                                                                                                                                                      |
| ------------------------------ | ------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `apparentCoordinates`          | degrees             | [equatorial](https://en.wikipedia.org/wiki/Equatorial_coordinate_system) right ascension (`ra`, α) and declination (`decl`, δ)                                                                                   |
| `apparentLongitude`            | degrees             | apparent geocentric [ecliptic](https://en.wikipedia.org/wiki/Ecliptic_coordinate_system) longitude (`λ`)                                                                                                         |
| `argOfLatitude`                | degrees             | Moon's argument of latitude: the mean distance of the Moon from its ascending node                                                                                                                               |
| `dateTD`                       | none                | Time stamp in dynamical time, i.e. adjusted for `deltaT`                                                                                                                                                         |
| `eclipticCoordinates`          | degrees             | geocentric [ecliptic](https://en.wikipedia.org/wiki/Ecliptic_coordinate_system) longitude (`λ`) and latitude (`β`) of the body referenced to the true equinox of date                                            |
| `equatorialHorizontalParallax` | degrees             | parallax that varies with the rotation of the Earth or with a difference in location on the Earth; typically only [significant for the Moon](https://en.wikipedia.org/wiki/Parallax_in_astronomy#Lunar_parallax) |
| `jde`                          | none                | Julian Ephemeris Day, i.e. Julian Day adjusted for `deltaT` expressed as fractional day                                                                                                                          |
| `meanAnomalyMoon`              | degrees             | [mean anomaly](https://en.wikipedia.org/wiki/Mean_anomaly) of the Moon                                                                                                                                           |
| `meanAnomalySun`               | degrees             | [mean anomaly](https://en.wikipedia.org/wiki/Mean_anomaly) of the Sun                                                                                                                                            |
| `meanElongation`               | degrees             | The Moon's [instantaneous angular distance](https://en.wikipedia.org/wiki/Orbit_of_the_Moon#Elongation) east of the Sun                                                                                          |
| `nutationInLongitude`          | degrees             | [nutation](https://en.wikipedia.org/wiki/Astronomical_nutation) in ecliptic longitude                                                                                                                            |
| `nutationInObliquity`          | degrees             | [nutation](https://en.wikipedia.org/wiki/Astronomical_nutation) in obliquity of the ecliptic                                                                                                                     |
| `obliquityOfEcliptic`          | degrees             | [obliquity of the ecliptic](https://en.wikipedia.org/wiki/Ecliptic#Obliquity_of_the_ecliptic): the inclination of Earth's equator with respect to the [ecliptic](https://en.wikipedia.org/wiki/Ecliptic)         |
| `radiusVector`                 | au (sun), km (moon) | distance from body to Earth, measured between centers                                                                                                                                                            |


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