[tag:astrometry] > [Astrometry][1] is the branch of astronomy that involves precise > measurements of the positions and movements of stars and other > celestial bodies. The information obtained by astrometric measurements > provides information on the kinematics and physical origin of our > Solar System and our galaxy, the Milky Way. This tag doesn't yet exist, so it might be worth adding it beforehand, if this suggestion is accepted for a TOTW. But since we recently launched ESA's Gaia towards a Lissajous orbit at Sun-Earth L2 Lagrange point and is tasked with mapping one billion stars of the Milky Way (only ~ 1%, but still a feat with no comparison if all goes well), measure precise distance to them and track their movement with two 1000 megapixel cameras that are precise enough to detect a Euro coin from the surface of the Earth if it was placed on the Moon, or resolve a human hair from 1000 kilometers away, I thought this topic might be interesting enough to a wider audience. ;) [1]: https://en.wikipedia.org/wiki/Astrometry