Convert Spherical Coordinates to Cartesian Vector

Given spherical coordinates and a time at which they are valid, returns a vector of Cartesian coordinates. The returned value includes the time, as required by the vector structure.

Given spherical coordinates and a time at which they are valid, returns a vector of Cartesian coordinates. The returned value includes the time, as required by the vector type.

Usage

astro_vector_from_sphere(sphere, time)

astro_vector_from_sphere(sphere, time)

Arguments

sphere

A list with components:

lat

Latitude angle: -90..+90 degrees

lon

Longitude angle: 0..360 degrees

dist

Distance in AU

time

POSIXct time at which the coordinates are valid

Value

A list representing a Cartesian vector with elements:

• x, y, z: Cartesian coordinates in AU

• t: Time value

• status: Status code (0 = success)

A list representing a vector with components:

x

The Cartesian x-coordinate in AU

y

The Cartesian y-coordinate in AU

z

The Cartesian z-coordinate in AU

t

The date and time (POSIXct) at which this vector is valid

status

Status code (0 = success)

Examples

sphere <- list(lat = 45, lon = 90, dist = 1.5)
time <- as.POSIXct("2024-01-01 12:00:00", tz = "UTC")
vec <- astro_vector_from_sphere(sphere, time)

# Convert spherical to Cartesian
sphere <- list(lat = 0, lon = 0, dist = 1)
time <- as.POSIXct("2024-01-01", tz = "UTC")
vec <- astro_vector_from_sphere(sphere, time)