Quick Start

After installation and setting SPICE_PATH, use the CLI entry point:

ephemeris-tools <command> [options]

To install the bundled web forms and sample files (for CGI deployment), run:

install_ephemeris_tools_files /path/to/your/tools/dir

Commands

  • ephemeris – Generate time-series ephemeris tables (positions, geometry)

  • tracker – Generate moon tracker PostScript plots and optional text tables

  • viewer – Generate planet viewer PostScript diagrams (planet, moons, rings, stars)

Ephemeris table

ephemeris-tools ephemeris --planet saturn --start "2025-01-01 00:00" \
    --stop "2025-01-01 02:00" --interval 1 --time-unit hour \
    -o ephem.txt

Key options (see Ephemeris command for the full list):

  • --planet: Planet number or name. Default: 6 (saturn).

  • --start, --stop: Start/stop time strings (required).

  • --interval: Time step size. Default: 1.0.

  • --time-unit: Unit for interval (sec/min/hour/day). Default: hour.

  • --ephem: Ephemeris version index; available versions are listed in SPICE_planets.txt. Default: 0.

  • --columns: Column IDs or names (e.g. ymdhms radec phase). Default: 1 2 3 15 8.

  • --moons: Moon indices or names (e.g. mimas titan). Default: none.

  • -o: Output file (default: stdout).

  • -v / --verbose: Set log level to INFO.

Moon tracker

ephemeris-tools tracker --planet saturn --start "2025-01-01 00:00" \
    --stop "2025-01-02 00:00" --moons mimas enceladus titan \
    -o tracker.ps

Key options (see Tracker command for the full list):

  • --planet, --start, --stop, --interval, --time-unit: same as ephemeris.

  • --moons: Moons to plot. Default: standard set for the planet.

  • --rings: Ring option codes or names (e.g. main ge or 61 62). Default: none.

  • --xrange: X-axis half-range. Default: auto-calculated.

  • --title: Plot title. Default: none.

  • -o: PostScript output file.

Converting PostScript to PNG (Ghostscript):

gs -dSAFER -dBATCH -dNOPAUSE -sDEVICE=png16m -r150 -sOutputFile=tracker.png tracker.ps

Planet viewer

ephemeris-tools viewer --planet saturn --time "2025-01-01 12:00" \
    --fov 0.1 --fov-unit deg -o view.ps

Key options (see Viewer command for the full list):

  • --planet: same as ephemeris. Default: 6 (saturn).

  • --time: Observation time (required).

  • --fov: Field of view size. Default: 1.0.

  • --fov-unit: FOV unit (deg/arcmin/arcsec/mrad/urad/km, planet radii, or instrument name). Default: deg.

  • --center: Diagram center (body/ansa/J2000/star). Default: body.

  • --moons: Moon indices or names. Default: planet default.

  • -o: PostScript output file.

  • --output-txt: Field-of-view text table file.

Converting PostScript to PNG (Ghostscript):

gs -dSAFER -dBATCH -dNOPAUSE -sDEVICE=png16m -r150 -sOutputFile=view.png view.ps

For detailed per-argument documentation, see Command-line interface. For column IDs, moon names, and observatory names, see Argument reference.