A site of importance as “Britain’s oldest purpose-built scientific institution,” Greenwich’s Royal Observatory, located in Greenwich Park, celebrates its 350^th anniversary in June 2025. King Charles II ordered the creation of the Royal Observatory to advance knowledge in navigation and astronomy, focusing on the study of longitude to increase safety in sea travel. As sea trade was imperative for the economy and relations between countries, it was important to ensure that sailors, ships, and their goods remained safe and knowledgeable about their position while on the seas. The architects built the observatory upon the old Greenwich Castle as that land already belonged to the British monarchy and the land was secluded yet close enough to London (“History of the Royal Observatory”).

James Bradley was the third Astronomer Royal in 1742-1762 who had made over 60,000 observations in this time frame. The title Astronomer Royal, created by King Charles II, is treated as an honor given to renowned astronomers that advise the crown in matters of astronomy (“The Astronomer Royal”). Astronomy work ran in his family as his uncle, Reverend James Pound, was a leading astronomical observer in England with a connection to second Astronomer Royal Edmond Halley, whom they both worked with. He was best known for two discoveries: the aberration of light, “which produces an apparent motion of celestial bodies about their true positions,” and the nutation of the Earth's axis, the variation over time of the axis of rotation’s orientation, caused by gravitational forces (Falconer et al.). Bradley’s observations “are the earliest from anywhere in the world whose accuracy and consistency is such, that are still of use to astronomers today” (Dolan).

During his time as an Astronomer Royal, he also worked on observing the moon and Jupiter, updating the equipment at the Observatory, and defined the Bradley meridian used in the Ordnance Survey (“James Bradley”). His work helped lead to the world’s inclusion of the Greenwich Meridian and Greenwich Mean Time. Unfortunately, none of his observations were published until 1798, aside from two published by Edmond Halley in 1718.

Works Cited:

Dolan, Graham. “The Royal Observatory Greenwich – A Brief History.” The Royal Observatory Greenwich, The Royal Observatory Greenwich, 2014, http://www.royalobservatorygreenwich.org/articles.php?article=1

Falconer, I.J.; Mena, J. G.; O’Connor, J.J.; Peres, T.S.C.; & Robertson, E.F.  “James Bradley.” MacTutor, 2018, https://mathshistory.st-andrews.ac.uk/Biographies/Bradley/#:~:text=Bradley%20was%20best%20known%20for,the%20velocity%20of%20the%20observer

“History of the Royal Observatory.” Royal Museums Greenwich, https://www.rmg.co.uk/royal-observatory/history

“James Bradley.” Royal Museums Greenwich, https://www.rmg.co.uk/collections/objects/rmgc-object-203215
• https://www.rmg.co.uk/collections/objects/rmgc-object-203215 (Picture) 3

“The Astronomer Royal.” Royal Museums Greenwich, https://www.rmg.co.uk/stories/topics/astronomer-royal

Wilson, Benjamin. James Bradley. ca. 1750, National Maritime Museum, Greenwich, London