Derby and District Astronomical Society
Royal Observatory, Greenwich
Saturday 9th August 2025
Article by Mike Lancaster
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On Saturday 9th August 2025 a group of DDAS members visited the Royal Observatory, Greenwich. The trip was to mark the 350th anniversary of the foundation of the Royal Observatory on the 10th August 1675 by John Flamsteed of Derby, England's first Astronomer Royal. We met up on the Saturday morning with Yvonne Jacobs from the Flamsteed Society, who would be our host for most of the day, and Bobby Manoo, Flamsteed Society Chair. First on the agenda were a couple of talks held in the Galaxy Room in the South Building. These were attended by our group as well as members of the Flamsteed Society. I began by giving a talk on John Flamsteed, primarily looking at his life and work in Derby, and also summarising his time at Greenwich, as well as recent efforts to preserve his former home on Queen Street in Derby. This was followed by a talk on Flamsteed's legacy at Greenwich by Dr Louise Devoy, Senior Curator at the Royal Observatory. Louise covered the history of the observatory since Flamsteed, and the contributions of the various astronomers royal through time.
After the talks and a spot of lunch we gathered in the Meridian Courtyard to witness the 1 pm time ball drop. We were then given a tour of the Royal Observatory by guides Mike Dryland and Brendan Cooper, taking in Flamsteed House, the Octagon Room, the various meridian telescopes, the famous Harrison Clocks, and the Great Equatorial Telescope. We also got a chance to do a spot of solar observing from the Astronomer's Garden with Flamsteed Society members. A number of us also got to tour the Cutty Sark, and finally, as some spare seats were available, Yvonne was able to arrange for DDAS member Mike Dumelow and myself to attend a planetarium show based around the night sky from Greenwich on the evening of its foundation in 1675. A big thank you to Yvonne and the Flamsteed Society for hosting our visit, and to our tour guides Mike and Brendan, and to Louise for giving such a fascinating talk. Finally, thanks must also go to DDAS Outreach Officer Brian Dodson for organising the visit. |
| Next two photos: The Royal Observatory from Greenwich Park. Image Credit: Mike Lancaster. |
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| DDAS members outside the Royal Observatory. Image Credit: Dave Selfe. |
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| Delivering my talk on John Flamsteed. Image Credit: Mike Dumelow. |
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| Flamsteed House. Image Credit: Mike Lancaster. |
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| The 1 pm Time Ball Drop. Video Credit: Dave Selfe. Commentary by Mike Dryland and the assembled crowd! |
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| DDAS members, together with Yvonne from the Flamsteed Society, assemble with our guides Mike and Brendan in the Meridian Courtyard. Image Credit: Mike Dumelow. |
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| Next two photos: Mike Dryland shows DDAS members around the famous Octagon Room inside Flamsteed House. Image Credit: Mike Dumelow. |
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| Line marking the position of the meridian wall upon which Flamsteed mounted his 140° mural arc in 1689. Image Credit: Mike Lancaster. |
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| The site of Flamsteed's 100 foot deep Well Telescope, which was the first zenith telescope to be used at Greenwich, but was ultimately a failure. Image Credit: Mike Lancaster. |
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| Next two photos: James Bradley's zenith telescope, with which he discovered the aberration of starlight and the nutation (wobbling) of the Earth's axis of rotation. The aberration of starlight was due to the Earth's motion around the Sun, and thus directly proved the Copernican theory. Image Credit: top: Mike Lancaster, bottom: Mike Dumelow. |
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| Halley's mural quadrant. Image Credit: Mike Lancaster. |
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| Royal Observatory volunteer Brendan Cooper shows us Edward Troughton's 10-foot transit instrument, which was installed in 1816. Image Credit: Mike Lancaster. |
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| Next two photos: The Airy Transit Circle, which sits on the Prime Meridian of the world. Image Credit: Mike Dumelow. |
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| The Onion Dome and Meridian Galleries. Image Credit: Jim Sarsgard. |
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| The Onion Dome. Image Credit: Jim Sarsgard. |
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| The Great Equatorial Telescope inside the Onion Dome. Image Credit: Mike Lancaster. |
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| The remains of William Herschel's 40 foot reflecting telescope. Image Credit: Dave Selfe. |
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| John Harrison's famous H1 marine timekeeper. Image Credit: Mike Dumelow. |
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| John Harrison's H4 marine timekeeper that eventually won him the longitude prize. Image Credit: Mike Dumelow. |
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| Next two photos: In the Astronomer's Garden behind Flamsteed House is this fine sundial, designed by Christopher St. J H Daniel. The narrow space between the dolphin's tails projected onto the dial face indicates the time. Jim Sarsgard, who took the photos, comments: "It is extremely accurate. The time indicated is shortly before 12:20. I took the photo at 12:16. The curvature of the time lines on the dial compensates for the fact that sundials run fast or slow compared with clocks. Also, the dial face is changed when Summer Time is in effect." Image Credit: Jim Sarsgard. |
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| DDAS members on board the Cutty Sark. Image Credit: Mike Dumelow. |
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| Looking northwards across Greenwich Park from the Royal Observatory towards the Queen's House, the Old Royal Naval College and the sky scrapers of Canary Wharf beyond. Image Credit: Mike Lancaster. |
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| The famous Tulip Stairs inside the Queen's House, Greenwich. John Flamsteed stayed in this house while the Royal Observatory was being constructed. Image Credit: Mike Lancaster. |
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Accounts of a couple of previous DDAS visits to the Royal Observatory at Greenwich may be found here: DDAS Visit to the Old Royal Observatory in Greenwich - Saturday 28th February 2015 DDAS Visit to the Royal Observatory, Greenwich - Saturday 25th October 2008 |
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