(Re)Displaying longitude

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This week's blog comes from Louise Devoy, Curator of the Royal Observatory

We’ve had a few months to refresh the Time and Longitude Gallery after the de-installation of Longitude Punk’d but it’s flown by like a 60-minute TV makeover programme! After the success of last year’s exhibition Ships, Clocks and Stars, many of the featured objects will be going on tour to venues in the United States and Australia. While this is a great opportunity to share our objects with new audiences, it’s been a logistical challenge trying to identify similar objects to fill the depleted displays at the Observatory. After many months of preparation, the new displays are starting to take shape and will soon be reopened for all visitors to enjoy from 16 March 2015 onwards.

Situated within the oldest part of the Royal Observatory, the Time and Longitude gallery is located within Flamsteed House. It’s an important space for us to show how the Royal Observatory played a pivotal role in the quest to determine longitude at sea during the 18th century. The first part of the gallery will tell the same story as before with a range of traditional navigational instruments, pendulum clocks and an explanation of why navigators struggled to use these devices to determine longitude at sea. This area is peppered with dramatic stories of shipwrecks and culminates with the Act of Longitude in 1714.

In the second part of the gallery, we introduce the two main approaches used in solving the longitude problem: one involved using astronomical methods to compare your local time against a known home time at port, while the other was based on similar principles using a timekeeper that could function at sea. While the timekeepers made by John Harrison will be back on display in their previous cases, the astronomical method display case has been completely overhauled to explain how the lunar distance method was transformed from theory into practice, thanks to the meticulous work of mathematicians, astronomers, instrument makers and navigators. We’ve worked hard to highlight the role of the Observatory, particularly the work of the fifth Astronomer Royal, Nevil Maskelyne, and the production of the Nautical Almanac from 1767 onwards.

F5064 Maskelyne pastel ZBA4305

Our emphasis on the work of the Observatory continues in the final case where we’ve selected a few examples of the marine chronometers which were tested at the ROG from 1840 onwards. Thanks to some digital design wizardry, we’ve been able to take an image from an atlas made in 1860 to create a wall graphic which illustrates the voyages on which these chronometers were taken around the globe - it’s a great visual addition to the display. Similarly, we’ve been inspired by the bold wall graphics of Longitude Punk’d to add new graphics throughout the gallery, from portraits and quotations to large scale maps and a new ‘Design your own navigational instrument’ area for your creative comments. We’ve also tried to weave in some of the digital content developed for Ships, Clocks and Stars such as the explanatory animation for the lunar distance method and a detailed view inside Harrison’s fourth timekeeper, ‘H4’.


As you leave the gallery, you will see a giant sketch of the Time ball on the roof of Flamsteed House, as seen in the Illustrated London News in November 1844. It’s a bold visual reminder of how all this new knowledge and technology was used in practice and a great way to introduce these themes before they’re explained in more detail in the exhibits of the Time and Greenwich Gallery.

More behind-the scenes stories from Time and Longitude in the next few weeks