Calendars and Calculators

The tools and information linked from this page will be useful for all the aspects of observations that are related to the position of the target: their visibility, sun- and moon-rise and -set, ephemerides for Solar System minor bodies, etc.


  • Calculation of Site Sky Ephemerides
    This tool produces a nightime calendar of phenomena for a single site.
  • Solar System Ephemerides: JPL HORIZONS service & IMCCE service hosted through ESO Moving Targets Procedures page
    The JPL HORIZONS on-line solar system data and ephemeris computation service provides access to key solar system data and flexible production of highly accurate ephemerides for solar system objects. The IMCCE service provides the same data in PAF format that needs to be used for ESO Observing Blocks preparation.
  • Object Observability
    This tool provides object observability tables based on site, object coordinates and observing period.
  • Daily Almanac
    This tool produces almanac data for a single site and for a single date. Provided by courtesy of J. Thorstensen and B. Casey.
  • JD converter: Converts civil date to julian date and reverse

Position, Airmass, Extinction

ETCs and Units Conversion