Astrometry is the branch of astronomy that focuses on measuring the positions and movements of celestial objects. This includes stars, planets, and other astronomical bodies. By accurately determining their locations in the sky, astronomers can track their orbits and understand their physical properties. The data collected through astrometry is essential for various applications, such as mapping the Milky Way galaxy and discovering new exoplanets. It also helps in understanding the dynamics of star clusters and the gravitational effects of dark matter in the universe.