HorizonsEphemeris
A wrapper around the wrapper around JPL's REST API for the HORIZONS solar system ephemeris platform!
Please consider all minor changes breaking until v1.0!
Warning
This package is not affiliated with or endorsed by NASA, JPL, Caltech, or any other organization! This is an independently written package by an astrodynamics hobbyist.
Installation
Choose one of the following two lines!
julia> ]add HorizonsEphemeris
julia> import Pkg; Pkg.add("HorizonsEphemeris");Limitations
Note that JPL Horizons ephemeris accuracy for major planetary bodies in the solar system may have errors larger than 1000km at some times!
Usage
As of v0.1, only Cartesian vectors are supported. You can query the
ephemeris function with any solar system body name, or
NAIF code;
HorizonsEphemeris uses SPICE under
the hood to return the appropriate Horizons-compatible NAIF code. After
providing the desired solar system body, specify the start time, stop time, and
step size for which you want ephemeris data. You'll receive a NamedTuple in
return. The labels for each key can be changed with the header keyword. For
example, to get rid of the Unicode character keys, specify
header=[:MJD, :Calendar, :X, :Y, :Z, :DX, :DY, :DZ]. This NamedTuple output
is automatically compatible with DataFrames. Finally, use the file keyword
argument to write the resulting ephemeris data, with labels, to a provided
filename as a CSV file.
julia> using Plots, Dates, HorizonsEphemeris
julia> earth = let start = now() - Year(50), stop = now() + Year(50), step = Day(1)
@time ephemeris("earth", start, stop, step; wrt="jupiter", units="AU-D");
end
# 6.376672 seconds (19.78 k allocations: 21.253 MiB)
julia> plot(
earth.X, earth.Y;
aspect_ratio = 1,
linewidth = 1.5,
border = :none,
size = (600, 600),
dpi = 200,
grid = false,
axis = nothing,
title = "",
label=:none,
color = "green",
background=:transparent,
)