BackForwardInstrument:  VIRGO 

Instrument details
Acronym VIRGO
Full name Variability of Solar Irradiance
Purpose Global and low resolution imaging of oscillating and solar constant
Short description The total irradiance is measured by active cavity radiometers, the spectral irradiance by three-channel sunphotometers, and the radiance over 12 resolution-elements on the solar disk by a Luminosity Oscillations Imager (LOI).
Background Part of a package of instruments to observe the solar atmosphere
Scanning Technique Sun pointing from the L1 Lagrange libration point
Resolution N/A
Coverage / Cycle Continuous from the L1 Lagrange point
Mass Power Data Rate


Providing Agency ESA
Instrument Maturity Flown on an R&D satellite
Utilization Period: 1996 to 2025
Last update: 2021-06-23
Detailed characteristics
Satellites this instrument is flying on

Note: a red tag indicates satellites no longer operational, a green tag indicates operational satellites, a blue tag indicates future satellites

Instrument classification
  • Earth observation instrument
  • Passive optical radiometer or spectrometer
  • Solar irradiance monitor
WIGOS Subcomponents
  • Subcomponent 1
  • Absolutely calibrated broadband radiometers, and TSI and SSI radiometers
  • TSI and SSI radiometers (for solar irradiance)
Mission objectives
Primary mission objectives
  • Downward short-wave irradiance at TOA
Evaluation of Measurements

The following list indicates which measurements can typically be retrieved from this category of instrument. To see a full Gap Analysis by Variable, click on the respective variable.

Note: table can be sorted by clicking on the column headers
Note: * Primary mission objective.
VariableRelevance for measuring this variableOperational limitationsExplanation
Downward short-wave irradiance at TOA*1 - primaryNo specific limitation.Coupled TSI (UV to TIR) and spectral irradiance (VIS to NIR)