 Originally , the light had a fifth @-@ order Fresnel lens , but a fourth @-@ order Fresnel lens was installed in May 1902 , just three months into its operation . The light characteristic was a fixed white light with a red flash every 15 seconds . In 1972 , the light was automated and the Fresnel lens was replaced with a modern <unk> . The light continues to serve as an active aid to navigation . In 1987 , a FA @-@ 251 was installed before the current lens , a <unk> @-@ 25 was installed . The current light characteristic is an alternating white and red flash every 24 seconds . The white and red flashes can be seen for 18 nautical miles and 15 nautical miles , <unk> . 
