The first given name of the physicist whose surname names the Doppler effect is Christian. He is generally known as Christian Doppler, although historical records give his fuller name as Christian Andreas Dopler.
Doppler was born in Salzburg on 29 November 1803. He became an Austrian mathematician and physicist, and in 1842 proposed that the observed frequency of a wave depends on the relative motion of its source and observer. That principle later became known as the Doppler effect.
A common mix-up is the name Johann Christian Doppler. That form appeared decades after his death through an error by astronomer Julius Scheiner and was copied by later writers. Doppler himself used Christian Doppler, while his birth and baptismal records used the Latin form Christianus Andreas Dopler. He died in Venice in 1853, but his scientific legacy now spans sound, astronomy, radar, medical ultrasound, and satellite communications.