BackForwardInstrument:  SEM (SOHO) 

Instrument details
Acronym SEM (SOHO)
Full name Solar EUV monitor
Purpose Measurement of the solar EUV radiation
Short description Fluxmeter to measure the solar EUV radiation at the He II 30.4 nm line and in the integrated range 17-70 nm
Background Component of the Charge, Element, Isotope Analysis instrument (CELIAS) addressing energetic particles
Scanning Technique Sun pointing from the L1 Lagrange libration point
Resolution N/A (full disk)
Coverage / Cycle Full solar disk at 1 s intervals
Mass Power Data Rate


Providing Agency DLR
Instrument Maturity Flown on an R&D satellite
Utilization Period: 1996 to 2025
Last update: 2021-09-29
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
  • Solar and space environment monitors
  • Solar activity monitor
WIGOS Subcomponents
  • Subcomponent 2
  • Solar magnetograph, solar EUV/X-ray imagery and EUV/X-ray irradiance, both on the Earth-Sun line and off the Earth-Sun line
  • Solar EUV spectrometer [from L1, GEO, LEO]
Mission objectives
Primary mission objectives
  • Solar EUV flux
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
Solar EUV flux*4 - fairNo specific limitation.Few channels, moderate dynamic range