empyrean.download_data

download_data(*, data_dir=None)

Provision a usable data directory with the required SPICE kernels.

Provisions the OS-appropriate XDG data directory by default (see default_data_dir()); pass data_dir to target another. Idempotent: files already present are kept; only missing files are downloaded.

If the B612 Foundation data packages (naif-de440, jpl-small-bodies-de441-n16, naif-eop-high-prec, naif-eop-historical, naif-eop-predict, mpc-obscodes) are installed and no explicit data_dir is given, their kernels are staged from the installed wheels with zero network access, and only what they do not supply (e.g. bias.dat) is downloaded.

Parameters:

data_dir (str | Path | None) – Target directory. Defaults to the value returned by default_data_dir() (honors EMPYREAN_DATA_DIR).

Return type:

str

Returns:

str – Path to the provisioned data directory.