Gaia is an European Space Agency space observatory designed to map stars and other astronomical objects using Astrometry. It has two 1.45 x 0.5 meter telescopes viewing the Optical range as well as very Near Infrared. It was launched in 2013 for a five year mission at the L2 Earth-Sun Lagrangian Point. Instruments:
A resulting Catalog was released as Gaia Data Release 1 (Gaia DR1) in 2016 and then Gaia Data Release 2 (Gaia DR2) in 2018. The Gaia-ESO Survey (GES) is a Survey conducted with Gaia and European Southern Observatory Very Large Telescope of 100,000 stars in four Open Clusters using Gaia astrometric data and Spectroscopy using a VLT Multi-Object Spectrograph.
European Space Agency (ESA)
Young Stellar Object (YSO)