Engineers from Dublin City Council have replaced the temporary light on top of Dublin's new 120-metre Spire, which was damaged by wind.
The Irish Aviation Authority said the temporary light was essential, pending the insertion of a permanent 12-metre light on the monument.
When the permanent lighting is in place, light will be diffused throughout the top 12 metres of the structure, through 11,884 tiny perforations.
The permanent lighting system, which it is hoped will be in place next week, will be inside the monument and will be protected from the weather.