General

  •  SIMBAD - Astronomical database.
  •  SkyView - Virtual observatory.
  •  VizieR - Astronomical catalog service.
  •  Gator - NASA/IPAC infrared and submillimeter database .
  •  USNO - Astronomical data services offered by the US Naval Observatory.

    • Molecular Spectroscopy

  •  JPL Molecular Spectroscopy - JPL list of molecular transition frequencies.
  •  Lovas's Line List - NIST Recommended Rest Frequencies for Observed Interstellar Molecular Microwave Transitions.
  •  LAMDA - Leiden Atomic and Molecular Database.

    • Ephemerides

  •  JPL Solar System Ephemeris - Web interface for solar system object positions.

    • Other

  •  Astronomical Constants - cgs units.