Berlenga Lighthouse

The Berlenga Lighthouse, officially known as the Duke of Bragança Lighthouse, is a historic structure located at the summit of Berlenga Grande Island in the Atlantic Ocean, Portugal. The island, a granite mass anchored several miles off the coast northwest of Peniche, hosts the lighthouse at its highest point, at coordinates 39º 24',99 N latitude and 09º 30',47 W longitude. The lighthouse is operated by the Portuguese Navy Directorate of Lighthouses (Direção de Faróis) and remains an active coastal aid to navigation.

The construction of the lighthouse was first ordered by the Pombaline Decree of 1 February 1758, establishing its historical origins in the 18th century. However, after a prolonged delay following this initial decree, the actual construction process gained momentum with the Ministry of Finance Decree of 12 December 1836. Under the supervision of engineer Gaudêncio Fontana, the tower was completed in 1841 and officially commissioned in 1842. The structure was built as a navigational reference point to guide ships approaching ports such as Lisbon and Porto and to enhance maritime safety in the hazardous waters of the Atlantic. The attached residential buildings were completed in the years following the tower’s construction, between 1851 and 1860.

^{Berlenga Lighthouse (}Flickr⁾

The Berlenga Lighthouse is a square prismatic tower constructed of masonry and ashlar stone corners, featuring a balcony at its summit. The white-walled tower stands 29 metres high, with a red lantern room and balconies. The light source is positioned 121 metres above sea level.

Since its commissioning, the lighthouse has undergone several technological upgrades:

• First System (1842): The initial lighting system consisted of a catoptric device with sixteen Argand lamps fueled by oil and equipped with parabolic reflectors. This system rotated via a clockwork mechanism, producing white light with a three-minute eclipse and a flash every ten seconds.

• Hyper-Radiant Optics (1897): One of the lighthouse’s key optical upgrades was the installation on 6 November 1897 of a Fresnel hyper-radiant optical apparatus. Powered by incandescent petroleum vapor, this device produced a group of three flashes every 30 seconds, becoming one of only two such optics installed in Portuguese lighthouses of this type.

• Electrification and Range Increase (1926): In 1926, the lighthouse was electrified using generator motors. This modernization increased the light intensity to approximately 27 million candlepower, extending the range to 36 nautical miles.

• Automation and Transition to Solar Power (1985–2000): The lighthouse was automated in 1985, eliminating the need for resident keepers. The original hyper-radiant optic was removed and replaced with a PRB 21 unit. The most significant environmental transformation occurred in 2000, when both the lighthouse and residential buildings switched entirely to solar power. During this transition, a modern rotating beacon, the TRB-400, was installed. In 2009, the TRB-400 was replaced by two LED optics. The current light characteristic is Fl W 10s (White Flash every 10 seconds), with an estimated range of 20 nautical miles.

^{Berlenga Lighthouse Architecture (}Flickr⁾

Since 1985, the lighthouse has been operated entirely automatically. There are no permanent lighthouse keepers stationed at the tower. Monitoring and maintenance are carried out remotely by the Portuguese Navy Directorate of Lighthouses from the mainland.

The lighthouse is directly protected and managed by the Portuguese Maritime Authority (Autoridade Marítima Nacional) and the Navy Directorate of Lighthouses. Its historical significance, combined with the island’s status as a UNESCO Biosphere Reserve, ensures its preservation as both a cultural and environmental heritage site.

Although the lighthouse is a symbol of the island and a popular tourist attraction, it is currently closed to visitors indefinitely due to operational issues. Visitors may observe the lighthouse from a distance and enjoy nearby diving sites within this UNESCO-protected natural area.