Sagittarius A

Sagittarius A (Sgr A) is the supermassive black hole at the Galactic Center of the Milky Way. Seen from Earth it lies near the border of Sagittarius and Scorpius and is a bright, very compact radio source.

It was discovered in 1974 by Bruce Balick and Robert L. Brown. In May 2022 the Event Horizon Telescope released the first image of the accretion disk around it, the second black hole ever imaged after M87's. The orbits of nearby stars, especially S2, have been used to measure its mass.