BackForwardInstrument:  SODISM 

Instrument details
Acronym SODISM
Full name Solar Diameter Imager and Surface Mapper
Purpose Sun observation, Space weather - Monitoring from a terrestrial orbit
Short description Imaging the solar disk and high-resolution parts of its limb. Three filter wheels to select four channels in the VIS range 535.7 to 782.2 nm, and two in UV at 215 and 393.37 nm (Ca II-K line). Extremely accurate pointing (0.003 arcsec, with knowledge of 0.001 arcsec, corresponding to 42 and 14 km, respectively) to measure Sun diameter variations
Background New development
Scanning Technique Sun pointing from a dawn-dusk LEO
Resolution 750 km at Sun surface
Coverage / Cycle Full solar disk each about 10 s
Mass 22.5 kg Power 19 W Data Rate 26 kbps


Providing Agency CNES
Instrument Maturity Flown on an R&D satellite
Utilization Period: 2010 to 2014
Last update: 2021-10-02
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 UV spectrometer [from L1, GEO, LEO]
  • Solar UV imager [from L1, GEO, LEO]
  • Solar VIS spectrometer [from L1, GEO, LEO]
  • Solar VIS imager [from L1, GEO, LEO]
  • Subcomponent 3
  • UV spectral imagery (e.g. GEO, HEO, MEO, LEO)
  • UV spectral imager [from GEO, HEO, MEO, LEO]
Mission objectives
Primary mission objectives
  • Solar Ca II-K image
  • Solar UV image
  • Solar VIS image
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 UV flux4 - fairNo specific limitation.Few channels, moderate dynamic range
Solar UV image*3 - highNo specific limitation.Fluxmetry with high spatial resolution
Solar Ca II-K image*2 - very highNo specific limitation.Ca-II-K at 393.37 nm (UV/VIS boundary), high spatial resolution
Solar VIS flux3 - highNo specific limitation.Wide dynamic range
Solar VIS image*3 - highNo specific limitation.Fluxmetry with high spatial resolution
Solar white light image3 - highNo specific limitation.Fluxmetry with high spatial resolution, good coverage of the VIS range