Gaia: a revolution in positional astronomy

Almost everything about the Gaia satellite is ground-breaking and astonishingly ambitious. Located at Lagrange Point L2, 1.5 million km from Earth, it will, over the course of its 5+ year mission, survey around 1 billion objects to give positions, proper motions and parallaxes about 100 times more precise than any previous catalogue, as well as information on brightness, radial velocity and spectral type. These data will exceed in both quantity and quality all previous compilations by huge factors and allow analysts to study the structure, motions, composition and history of our Milky Way galaxy in unprecedented detail. The two tranches of data released to date have already provided fresh insights and, when the full catalogue is published in 2022, it will provide enough material to keep astronomers busy for decades to come.

This Month in Astronomy ~ David Pulley, Tony Baxter

Barnard's star,