Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI)

Christopher Eyles, George Simnett

Research output: Contribution to journalArticle

1158 Citations (Scopus)


The Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) is a five telescope package, which has been developed for the Solar Terrestrial Relation Observatory (STEREO) mission by the Naval Research Laboratory (USA), the Lockheed Solar and Astrophysics Laboratory (USA), the Goddard Space Flight Center (USA), the University of Birmingham (UK), the Rutherford Appleton Laboratory (UK), the Max Planck Institute for Solar System Research (Germany), the Centre Spatiale de Leige (Belgium), the Institut d'Optique (France) and the Institut d'Astrophysique Spatiale (France). SECCHI comprises five telescopes, which together image the solar corona from the solar disk to beyond 1 AU. These telescopes are: an extreme ultraviolet imager (EUVI: 1-1.7 R-circle dot), two traditional Lyot coronagraphs (COR1: 1.5-4 R-circle dot and COR2: 2.5-15 R-circle dot) and two new designs of heliospheric imagers (HI-1: 15-84 R-circle dot and HI-2: 66-318 R-circle dot). All the instruments use 2048x2048 pixel CCD arrays in a backside-in mode. The EUVI backside surface has been specially processed for EUV sensitivity, while the others have an anti-reflection coating applied. A multi-tasking operating system, running on a PowerPC CPU, receives commands from the spacecraft, controls the instrument operations, acquires the images and compresses them for downlink through the main science channel (at compression factors typically up to 20x) and also through a low bandwidth channel to be used for space weather forecasting (at compression factors up to 200x). An image compression factor of about 10x enable the collection of images at the rate of about one every 2-3 minutes. Identical instruments, except for different sizes of occulters, are included on the STEREO-A and STEREO-B spacecraft.
Original languageEnglish
Pages (from-to)67-115
Number of pages49
JournalSpace Science Reviews
Issue number1-4
Publication statusPublished - 1 Jan 2008


  • coronal mass ejections
  • XUV heliograph
  • heliosphere
  • coronal loops
  • stereo
  • solar corona
  • Lyot coronagraph
  • heliospheric imager


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