Rotation Matrix from EQD to HOR — astro_rotation_EQD

Calculates a rotation matrix from equatorial of-date (EQD) to horizontal (HOR).

Usage

astro_rotation_EQD_HOR(time, latitude, longitude, height)

Arguments

time: A POSIXct object representing the date and time at which the Earth's equator applies.
latitude: The observer's geographic latitude in degrees.
longitude: The observer's geographic longitude in degrees.
height: The observer's elevation above sea level in meters.

Value

A rotation matrix that converts EQD to HOR. The components of the horizontal vector are: x = north, y = west, z = zenith (straight up from the observer).

Details

This is one of the family of functions that returns a rotation matrix for converting from one orientation to another.

Source: EQD = equatorial system, using equator of the specified date/time.

Target: HOR = horizontal system (x = north, y = west, z = zenith).

Examples

astro_rotation_EQD_HOR(Sys.time(), latitude = -35.28, longitude = 149.12, height = 0)
#>            [,1]      [,2]       [,3]
#> [1,] -0.3011742 0.8532829 -0.4256786
#> [2,]  0.4928329 0.5214482  0.6965684
#> [3,]  0.8163393 0.0000000 -0.5775727