sentences:  The ELODIE spectrograph, installed at the Haute-Provence Observatory in Southern France in 1993, could measure radial-velocity shifts as low as 7 m/s, low enough for an extraterrestrial observer to detect Jupiter's influence on the Sun.Using this instrument, astronomers Michel Mayor and Didier Queloz identified 51 Pegasi b, a "Hot Jupiter" in the constellation Pegasus.Although planets had previously been detected orbiting pulsars, 51 Pegasi b was the first planet ever found orbiting a main-sequence star, and the first detected using Doppler spectroscopy.