Rathlin lighthouse dimmed by a double fault
It's famous as the building from where the world's first commercial radio signals were sent over water 118 years ago, but Rathlin Island's East Lighthouse has now suffered a communication problem.
One of Northern Ireland's most important lighthouses was unable to send out its full safety beam after a rare double failure.
It has been providing guidance for vessels on the busy North Channel shipping lane for 160 years - but not on Wednesday night.
Residents were quick to notice the lighthouse's reassuring beams had failed.
One man said: "People in places like Ballintoy noticed the light was not working because although it is over six miles away, the East Lighthouse beams light up the outside of houses there.
"But for the first time in living memory there was no light coming from the East Lighthouse and it was the talk of the area.
"Locals say it has not happened in their lifetime, and perhaps this is even the first time it has happened."
The problem was because of a rare double whammy - an electricity mains failure and then a faulty standby generator.
Captain Robert McCabe of the Commissioners of Irish Lights said yesterday: "Following a mains failure yesterday afternoon our standby generator at the Rathlin East light developed a fault.
"The light was not extinguished but was on reduced range overnight. Our technicians are attending the fault today and the light should be back on full power this evening."
Mr McCabe said the 'racon', a radar beacon that makes the lighthouse show up on ships' radars, continued to operate.
The lighthouse, high above Bruce's Cave at Altacarry Head, has been flashing a warning to mariners since 1856. It is the oldest of the lighthouses on Rathlin and is automated.
In 1898 Guglielmo Marconi was contracted by Lloyd's Insurers to install a wireless link. On July 6 that year Marconi transmitted the first commercial radio signals across water from the lighthouse to Ballycastle.