Key Points

• The Royal Observatory Greenwich plans to close temporarily all its buildings to the public starting November 2, 2026, and will undergo a significant redevelopment project worth £77 million.
• This project is called “The First Light” project and will take place in tandem with the 350th anniversary of this famous scientific establishment.
• Although complete completion and reopening is set for 2028, there are plans to reopen the Meridian Courtyard in the summer of 2027 so that visitors can start once again taking photos at the famous Prime Meridian line.
• Peter Harrison Planetarium was shut down in September 2025, but other parts of the facility were still open up until this temporary closure.
• This architectural reworking is managed by Jamie Fobert Architects as a solution to solve accessibility problems caused by historical organic growth of the facilities with the installation of step-free routes, garden walkway on the elevation and a lift tower for the Great Equatorial Telescope.
• While the development takes place, other astronomy programs, planetarium shows and events like the “Astronomers Take Over” gallery will be held in the National Maritime Museum.

London (South London News) September 12, 2026 — One of the capital’s most iconic and historic landmarks is preparing to shut its doors to the public for a massive structural overhaul. As reported by staff writer Katie Forge of Secret London, Britain’s oldest purpose-built scientific institution is mere moments away from closing its doors to the public to undergo a rather gargantuan glow-up. The Royal Observatory Greenwich has confirmed that its site will completely shutter all buildings starting from Monday, November 2, 2026, as part of a comprehensive £77 million redevelopment programme.

The extensive modernisation effort, officially titled “The First Light” project, has been designed to coincide with the landmark institution’s 350th anniversary. Originally designed in 1675 by Sir Christopher Wren, the observatory is a UNESCO World Heritage Site sitting atop a hill in Greenwich, serving globally as the historic home of Greenwich Mean Time (GMT) and the Prime Meridian line. Because the complex has expanded organically across three and a half centuries, it currently presents significant accessibility barriers, featuring narrow routes and steep gradients that staff have described as a logistical challenge for visitors.

What specific upgrades and architectural changes are planned during the closure?

The redevelopment blueprints, spearheaded by Jamie Fobert Architects—the firm renowned for the recent reinvention of the National Portrait Gallery—aim to resolve long-standing physical constraints across the historic site. As detailed by the architectural team from Jamie Fobert Architects, the new building elements were conceived as “instruments of navigation” to guide visitors around the complex, incorporating bronze pavilions and stairs that test the boundaries of an astronomical architectural language.

The transformation encompasses several major infrastructure upgrades. As reported by London Now journalist, the project will introduce a new elevated walkway across the garden linking the north and south sections, complete with landscaped, step-free paths and a new access tower equipped with a lift to finally allow visitors to reach the Great Equatorial Telescope. Furthermore, the master plan includes a brand-new exhibition space dedicated to fresh heritage displays, a redesigned main entrance pavilion, and internal gallery revamps featuring updated retail spaces and a reimagined café area known as the Astronomers Court.

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Where can visitors access astronomy experiences while the observatory is shut?

Although the primary hilltop site will be closed for structural work, public engagement with astronomy will continue nearby through alternative programming. As outlined in local coverage by Maritime Radio, visitors interested in astronomy will continue to have access to selected experiences coordinated by Royal Museums Greenwich at the nearby National Maritime Museum.

These alternative offerings include a temporary planetarium and an interactive “Astronomers Take Over” gallery where members of the public can meet active Royal Observatory astronomers, ask questions about space, and participate in science demonstrations. Families and visitors will also be able to experience “Unboxing the Universe,” a multi-sensory live science show, alongside an Astronomy LEGO® Brick Club exploring navigation, time, and space history through interactive block-building sessions.

Other major attractions managed by Royal Museums Greenwich—namely the National Maritime Museum, the Queen’s House, and the historic ship Cutty Sark—will remain open to the public as usual throughout the closure period.

When will the public be able to stand on the Prime Meridian line again?

While the broader construction timeline indicates that the Royal Observatory will not fully reopen until 2028, interim access provisions are currently being scheduled. As announced by Royal Museums Greenwich representatives, plans are actively underway to temporarily reopen the Meridian Courtyard during the summer of 2027. This interim reopening will allow tourists and astronomy enthusiasts to once again stand with one foot in the Eastern Hemisphere and the other in the Western Hemisphere, and take photographs on the iconic Prime Meridian line before final project completion.

Background of the Development

The Royal Observatory Greenwich holds a foundational place in the history of global science, navigation, and timekeeping. Established by King Charles II in 1675 with John Flamsteed appointed as the first Astronomer Royal, the institution was tasked with finding a celestial method for determining longitude at sea, which was critical for maritime navigation and expanding trade empires. Over centuries, it became the definitive zero point for longitude and universal time, culminating in the 1884 adoption of the Greenwich Meridian as the prime meridian of the world.

Despite its immense historical status, the physical infrastructure of the hilltop site struggled to keep pace with modern public accessibility standards and visitor capacity demands. Over the decades, incremental additions created a complex layout defined by steep gradients, narrow corridors, and fragmented garden paths. Recognizing the need to preserve its heritage while modernising for its upcoming 350th anniversary, Royal Museums Greenwich initiated “The First Light” project, securing initial funding to overhaul the campus, protect its historic instruments like the Great Equatorial Telescope, and create an inclusive environment for a modern global audience.

This £77 million redevelopment is expected to profoundly reshape the visitor economy and public educational engagement in southeast London. For tourists, international travellers, and London residents, the temporary closure until summer 2027 (and full completion by 2028) will mean a temporary loss of access to one of the capital’s most photographed geographical markers. However, the anticipated reopening of the Meridian Courtyard by summer 2027 will help mitigate long-term tourism disruption. For the audience of science enthusiasts, families, and local school groups, the modernisation will ultimately deliver a vastly improved, fully accessible campus with state-of-the-art interactive galleries, step-free pathways, and enhanced educational facilities that will future-proof the historic institution for generations to come.