Solar and Heliospheric Observatory

The Solar and Heliospheric Observatory (SOHO) is a spacecraft launched by the European Space Agency (ESA) and NASA in 1995 to study and monitor the Sun. It orbits the Sun-Earth L1 Lagrangian point. Instruments:

• CDS - Coronal Diagnostic Spectrometer.
• CELIAS - Charge, Element and Isotope Analysis System.
• COSTEP - Comprehensive Suprathermal and Energetic Particle analyzer collaboration.
• EIT - Extreme ultraviolet Imaging Telescope.
• ERNE - Energetic and Relativistic Nuclei and Electron experiment.
• GOLF - Global Oscillations at Low Frequencies.
• LASCO - Large Angle and Spectrometric Coronagraph.
• MDI - Michelson Doppler Imager.
• SUMER - Solar Ultraviolet Measurements of Emitted Radiation.
• SWAN - Solar Wind Anisotropies.
• UVCS - Ultraviolet Coronagraph Spectrometer.
• VIRGO - Variability of Solar Irradiance and Gravity Oscillations.

LASCO consists of three coronagraphs, termed LASCO C1, LASCO C2, and LASCO C3. The three vary in the size of the portion of the sky that they occult, and in the technology they use to do so.