BackForwardInstrument:  VELC 

Instrument details
Acronym VELC
Full name Visible Emission Line Coronagraph
Purpose VIS imagery and polarimetry of the Corona
Short description Imaging the corona by internal and external occultation, with polarisation observation. Exploiting three VIS channels: two narrow-band ones centred on the Iron lines at 530.3 and 637.4 nm respecively, that enable inference of magnetic and electric fields in the Corona, and one broadband centred on 580 nm
Background New development
Scanning Technique Sun pointing from the L1 libration point. It views the solar corona with occultation of the solar disc.
Resolution 1500 km at Sun surface
Coverage / Cycle Full solar corona at 1-s rate
Mass 120 kg Power 130 W Data Rate 750 kbps


Providing Agency ISRO
Instrument Maturity Flown on an R&D satellite
Utilization Period: 2022 to 2027
Last update: 2021-12-02
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 1
  • Solar coronagraph and radio- spectrograph, at L1
  • Solar coronographic imager at L1
  • 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 VIS spectrometer [from L1, GEO, LEO]
  • Solar VIS imager [from L1, GEO, LEO]
  • Solar magnetic field sensor [from L1, GEO, LEO]
  • Solar electric field sensor [from L1, GEO, LEO]
  • Solar coronagraph and heliospheric imagery both on the Earth-Sun line and off the Earth-Sun line (e.g. L5 point)
  • Solar coronographic imager [from L1, GEO, LEO]
Mission objectives
Primary mission objectives
  • Solar electric field
  • Solar magnetic field
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 VIS flux2 - very highLimited to the solar corona.Moderate dynamic range, solar disc occulted, polarisation capability
Solar magnetic field*4 - fairLimited to the solar corona.Fluxmetry with high spatial resolution, polarimetry exploited, solar disc occulted
Solar electric field*3 - highLimited to the solar corona.Fluxmetry with coarse spatial resolution, polarimetry exploited, corona view included
Solar coronagraphic image2 - very highNo specific limitation.VIS (400-700 nm), observed with occultation