Its sweeping beam has guided mariners to safety and cast long flickers of shadow and light across the westernmost edge of the Vineyard for many decades.
But now the Gay Head Light is slated for a lantern change, and in the process the beam will change from sweeping to pulsing.
Lieut. Matthew Stuck of the U.S. Coast Guard aids to navigation branch said recently that the Coast Guard plans to replace the optic rotating light with a flashing LED light sometime in the next few months. The current optic, installed in 1989, is outdated and replacement parts are scarce, Mr. Stuck said.