HARPS (High Accuracy Radial Velocity Planet Searcher) is a spectrograph with an echelle grating in the ESO 3.6m Telescope at La Silla Observatory (LSO) in Chile. Its spectral resolution is capable of detecting radial-velocity-differences down to 1 meter per second. It began operation in 2003 and is credited with discovering at least 130 extra-solar planets. HARPSpol is a term for HARPS using its polarimeter feature. The HARPS M dwarf sample is a astronomical catalog of about 400 M dwarves used for a study.