STEREO

STEREO (for Solar Terrestrial Relations Observatory) is two satellites in solar orbit able to take stereo images of solar phenomena. They were launched in 2006. Contact with one the two (STEREO-B) was lost in 2014 and has been out of use since, but the other (STEREO-A) is still collecting data as of 2024. Instruments included:

• SECCHI - Sun Earth connection coronal and heliospheric investigation: five cameras.
• IMPACT - in-situ measurements of particles and coronal mass ejection transients.
• PLASTIC - plasma and suprathermal ion composition.
• SWAVES - stereo/waves - radio burst tracker.

SECCHI included:

• EUVI - extreme ultraviolet imager.
• COR1 and COR2 - coronagraphs.
• HI1 and HI2 - heliospheric imagers.

EUVI, COR1, and COR2 together were termed SCIP, for Sun centered instrument package.

STEREO's observations also include some stars and STEREO has discovered over 100 eclipsing binaries.

An unrelated series of coordinated stereo solar observations termed STEREO-1, STEREO-2, etc., were carried out in the 1970s, consisting of French observations from the ground, and observations by Soviet Union Mars orbiters, including Mars 3 and Mars 5.