EarthOrientation.jl

Calculate Earth orientation parameters from IERS tables in Julia.

Installation

The package can be installed through Julia's package manager:

Pkg.add("EarthOrientation")

Quickstart

Fetch the latest [IERS][iers-link] tables:

using EarthOrientation
EarthOrientation.update()

Get the current Earth orientation parameters, e.g. for polar motion:

xp, yp = polarmotion(now()) # arcseconds

Or the current difference between UT1 and UTC and the associated prediction error:

ΔUT1 = getΔUT1(now()) # seconds
ΔUT1_err = getΔUT1_err(now()) # seconds

Available data

• Polar motion:
  • x-coordinate of Earth's north pole: getxp
  • y-coordinate of Earth's north pole: getyp
  • both: polarmotion
• Earth rotation
  • Difference between UT1 and UTC: getΔUT1
  • Excess length of day: getlod
• Precession and nutation based on the 1980 IAU conventions
  • Correction to the nutation of the ecliptic: getdψ
  • Correction to the obliquity of the ecliptic: getdϵ
  • both: precession_nutation80
• Precession and nutation based on the 2000 IAU conventions
  • Correction to the celestial pole's x-coordinate: getdx
  • Correction to the celestial pole's y-coordinate: getdy
  • both: precession_nutation00

There is an associated function that returns the prediction error for each data type, e.g. getxp_err.

Manual Data Management

By default the files downloaded by EarthOrientation.update() will be used. It is also possible to pass different finals.all and finals2000A.all files in CSV format.

using EarthOrientation

push!(EOP_DATA, "finals.csv", "finals2000A.csv")