A Special Day Learning about our Shared History – Visit to Herstmonceux Castle and Observatory – 7th June 2025

On Saturday 7th June, 56 of us headed to the deep south of East Sussex to visit Herstmonceux for the day. This is the biggest group we’ve ever had for a Flamsteed trip! The majority of the group were Flamsteed members, but we did have a few special guests from Orpington Astronomical Society and a staff member from Royal Museums Greenwich join us too.

Some drove to get there, and 36 of us took a coach from Greenwich. We all arrived for 10:30 for the start of our visit at the Castle. We were welcomed by Barry Howse (Operations Supervisor and Tour Guide at the Castle, also a keen amateur astronomer who previously worked at the Observatory for five years), who was our host this morning, and also John Fox, Chair, and other members of Wealden Astronomers, who are based there and joined us for the morning.

The first thing we did was a bit of a change of plan to take advantage of the fair weather (not raining!) and take a group photo in front of the Castle. John Fox is a professional photographer, and he and Lance got us organised and took this fantastic photo below. John even photoshopped himself into the photo (far right) – how lovely to have him in the photo too!

Most of the group in front of the Castle (photo by John Fox and Lance Maleski, Wealden Astronomers), and our photographer John Fox in action (photo by Bobby Manoo)

The Castle exterior (photos by Poly Philippou)

Then we assembled in one of the seminar rooms for a brief before we split into two groups for a talk on the history of the Castle, a tour of parts of the Castle, and a visit to the Gardens.

Barry gave us a comprehensive history of the Castle, from its origins dating back to the 15th century, when it was commissioned by Sir Roger Fiennes, Treasurer to the Household of Henry VI, through many changes in ownership, up to its purchase at auction in 1992 by industrialist and philanthropist Alfred Bader, and his donation of the Castle to Queen’s University in Canada – the current owners – as a gift in recognition of the university’s education and impact on his life. Due to problems with the building structure, the teaching facilities were moved out and major restoration works started in 2024, though the Castle and gardens remained open to the public. During the course of its long history, the Castle has, of course, had its fair share of the obligatory ghost stories – including those of the headless drummer!

Barry did not go into detail about the Royal Greenwich Observatory period, as we would be finding out much more about that in the afternoon, but he did touch upon the apartments of the first Astronomer Royal to live here, Sir Harold Spencer Jones, who arrived in 1948. The seminar room we were in was the Astronomer Royal’s dining room.

Due to the restoration works, only some parts of the Castle are open, but we were still able to visit the medieval chapel, ballroom, boardroom, great staircase and the library. Many of these spaces have changed considerably after being converted multiple times for storage, education, corporate and event use, but the old staircases, enormous rooms, spectacular ceilings, dramatic fireplaces, etc. are still there to see.

Photos of the Castle interior, including our host Barry (photos by Poly Philippou and Bobby Manoo)

The gardens were truly beautiful – full of ancient trees, floral colour and old and modern sculptures. The highlights of the garden for us were (of course!) the bust of John Flamsteed (looking rather grumpy, I must say!) and the giant sundial, inaugurated in 1975 by HRH Princess Anne, marking the 300th anniversary of the founding of the Royal Observatory Greenwich. We, of course, had to have our photo taken there too!

The group with John Flamsteed and the giant sundial (photos by John Fox and Lance Maleski, Wealden Astronomers)

More photos of the gardens (photos by Poly Philippou and Bobby Manoo)

Massive thanks to John and Lance for these great photos. John asked me to share Wealden Astronomers’ website – www.wealdenastronomers.org, where you can see John’s and other members’ images on the Astrophotography page and some amazing timelapse videos by John on the Astrophotography Videos page – including my favourites, some beautiful ones featuring the domes and telescopes at Herstmonceux.

Then we said goodbye to the Castle and our hosts there and walked up to the Observatory Science Centre (OSC) for the afternoon. Our hosts there were Ian Whiteley – Volunteer at the OSC and Chair of the Herstmonceux Observatory Campaign Group – and Sandra Voss, Science Director of the OSC.

For many of us, this was our first visit here, and I for one was quite taken aback by the site design and art deco-style architecture. Even though I had seen many photos before, I thought it was beautiful. We found out later during Ian’s talk (below) that the Observatory's main buildings, including the Equatorial Group of buildings, were designed by Brian O'Rorke, who had previously designed ocean liner interiors! These buildings were listed Grade II* in March 2003.

Beautiful architecture (photo from OSC)

After a break for lunch, we headed into the Geodesic Tent for a fantastic, informative and colourful talk by Ian Whiteley on the history of the Royal Greenwich Observatory at Herstmonceux. His talk was brought to life with short videos of interviews by Ian with some of the astronomers at Herstmonceux.

It was decided in the 1940s that the Royal Observatory at Greenwich needed a new home, primarily due to increasing light pollution. After a review of a number of possible locations, the Admiralty selected Herstmonceux (perhaps due to favourable viewing conditions here, or – Ian thinks – maybe because the Astronomer Royal wanted to live in a castle?!) and purchased the Castle and surrounding estate in 1947. The Royal Observatory moved from Greenwich to Herstmonceux, where it was expanded and renamed the Royal Greenwich Observatory. The move began in 1947 and took about 10 years, being completed in July 1958. The Astronomer Royal at the time, Sir Harold Spencer Jones, arrived in 1948. He had apartments in the Castle and, at about the same time, a number of huts were built as accommodation for his staff next to the Castle. The next Astronomer Royal, Sir Richard Woolley, moved here in 1956.

The first dome to be completed at Herstmonceux was the Solar Dome, near the Castle, south of the main site. It was completed and the photoheliograph was moved from Greenwich to here in 1949. The building caused quite a stir at the time – disliked by locals as it did not fit in with its surroundings. This dome was subsequently adapted for use by the Satellite Laser Ranging facility, or Geodesy facility.

The buildings of the main site, including the six domes known as the Equatorial Group, were started in 1947 and completed in 1958. They were designed to house the five large equatorials from Greenwich, together with a yet-to-be-designed Schmidt telescope. The green verdigris copper of the Equatorial Group domes fitted with the green surroundings, and the design was liked by the locals!

The Observatory remained at Herstmonceux until the end of the 1980s. In 1990, following a downsizing, it moved to Cambridge, where it remained until it was ultimately closed down in 1998. Meanwhile, at Herstmonceux, after a campaign to save the site for science – which included Sir Patrick Moore – in 1995 the Observatory Science Centre was opened with a science and public access remit.

Ian Whiteley talking to us in the Geodesic Tent (photos by Poly Philippou)

Ian also told us about some of the key research areas and discoveries made by the RGO here – the proper motion of stars, identification of quasars, and exploration of black holes – including the discovery of the first black hole, in Cygnus X-1, by Paul Murdin and Louise Webster in 1971.

There is so much information about the history of the RGO (including some of the photographs used in Ian’s presentation) on Graham Dolan’s website: http://www.royalobservatorygreenwich.org, which Ian recommended. Ian also recommended two books – Astronomers at Herstmonceux in their Own Words and The Isaac Newton Telescope at Herstmonceux and La Palma by Anthony Wilson. You can also see some of Ian’s interview videos on the OSC’s YouTube channel (though the more recent videos are not published there).

Ian ended his talk by reminding us that the site is again threatened with closure – the extension of the OSC’s lease at Herstmonceux is still not secured and the future of the Observatory Science Centre is still uncertain. He urged us to continue to support the campaign and to please visit www.herstmonceuxobservatory.com and sign the petition at https://www.change.org/SavetheOSC if you have not already done so.

Then we split into two groups again for the tours with Jarvis and Kit of the Equatorial Group of telescopes. There are six domes in this group, and the tour visited the five which still house the historical telescopes. Normally, only two of these are open to the public, so this was a real treat.

Huge thanks to Clive Inglis for writing up the telescope descriptions for the telescope tour, Domes A–E, below!

Dome A – The 30” f/47 Thompson Reflector, 1896

Donated to the Royal Observatory by Sir Henry Thompson in 1896, this telescope was mounted on the same mounting as the 26-inch Thompson refractor, both counterbalancing each other, in the South Building at Greenwich. While at Greenwich, it was used to photograph comets, asteroids, and the moons of the outer planets. In 1908, British astronomer Philibert Jacques Melotte discovered the 8th moon of Jupiter, later named Pasiphae.

The telescope was moved to Herstmonceux in the 1950s, where it was placed on an equatorial fork mount and used for spectroscopic studies of stars using a Coudé spectrograph – light from a star being projected from the telescope down through the observatory floor onto the spectrograph in the room below.

Dome A and the 30” Thompson Reflector (photos by Poly Philippou)

Dome B – The 36” f/15 Yapp Reflector, 1932

The 36-inch Yapp reflecting telescope was built in 1932 by Grubb Parsons of Newcastle-upon-Tyne and donated to the Royal Observatory by Mr William Yapp, a prominent industrialist. After 21 years of use at Greenwich, in the Christie Enclosure (this building no longer exists) – where it had been the largest working telescope – it was moved to Herstmonceux in 1958 and used for stellar spectroscopy and photometry.

Towards the end of its life, it was used to test equipment for use on other telescopes, such as the Isaac Newton.

Dome B and the 36” Yapp Reflector (photos by Poly Philippou)

Dome C – The 34” f/1 Hewitt Camera, 1962

A Schmidt-type camera system designed by Joseph Hewitt in the 1950s to track the Blue Streak ballistic missile. Of the two cameras built for the Blue Streak programme, this one was originally based at Evesham, Worcestershire, becoming operational in 1962. Following cancellation of the missile programme, this camera came to Herstmonceux in 1982. Here it was used to track satellites by photographing their path and measuring their motion relative to background stars. Each image covered an area of sky approximately equivalent to 20 times the width of the Moon. Analysis of a satellite’s orbit gave information on the Earth’s gravity field and the properties of the upper atmosphere.

Dome C and the 34” Hewitt Camera (photos by Poly Philippou)

Dome D – The 13” Astrographic Refractor, 1890

Built by Grubb in Dublin in 1890, this telescope was used to develop the new technique of astronomical photography, particularly as part of the Carte du Ciel international programme to map the entire sky in detail by photography. A second 10-inch refractor with a focal length of 11 feet, mounted on top of the main telescope, acts as a guide scope.

It was this telescope that took part in the 1919 total eclipse expedition to Brazil to verify Einstein’s General Theory of Relativity. Einstein predicted a change in the apparent position of stars close to the Sun due to the bending of light by the Sun’s gravity. This was observed, confirming Einstein’s theory.

The telescope was moved from Greenwich to Herstmonceux in 1958, where it was used to measure the proper motion of stars by comparing photographic plates with those taken many years earlier. It was also used for Solar System observations, mainly of the brighter asteroids.

Dome D and the 13” Astrographic Refractor (photos by Poly Philippou)

Dome E – The 26” f/10.4 Thompson Refractor, 1896

Originally used at the Royal Observatory Greenwich and housed in the South Building, this telescope was built by Grubb of Dublin in 1896 at a cost of £5,000. It was gifted to the Royal Observatory by Sir Henry Thompson, a London surgeon and amateur astronomer. With an aperture of 26 inches, it is the twelfth largest refracting telescope in the world and the second largest in Great Britain. The 26-inch objective lens is a doublet with a focal length of around 22.4 feet. The telescope has a smaller guide scope with an aperture of 12.8 inches and a focal length of 17.8 feet.

The telescope is fitted with a holder for six-inch square photographic plates and was used to make accurate measurements of the positions of stars to determine their motion and distance. In 1930–31, it took part in an international programme to track the asteroid Eros to determine the Earth–Sun distance.

In the 1960s, it was used to monitor the changing brightness of quasars, which can vary by as much as twenty times over a few months. This suggests that, although a quasar might be as bright as an entire galaxy, its size must be millions of times smaller. In 1969, Donald Lynden-Bell, an astronomer at the RGO, suggested that a massive black hole at the centre of a galaxy could power a brilliant quasar and predicted that most galaxies could contain such black holes.

Using measurements from the 26-inch of the galaxy NGC 4151 taken over several years – and data from the Ultraviolet Explorer satellite – RGO astronomers concluded that a supermassive black hole may indeed lie at the centre of this galaxy.

Dome E and the 26” Thompson Refractor (photos by Poly Philippou)

One of the domes of the Equatorial Group – Dome F – was not part of the tour, but some people visited it separately. This dome used to house our beloved Great Equatorial Telescope, which was returned to Greenwich in 1971. It now houses the Domes of Discovery exhibition, which tells the story of the Royal Observatory. Its centrepiece is the 38” Congo Schmidt telescope, made in 1960 and intended for an African observatory. The plan was abandoned, and in 1972 the telescope was brought to Herstmonceux and installed here. Also in this dome – and a definite favourite for many in our group, especially as we had seen plates from the expedition at the RAS Library in March – is the lens used by Eddington in the 1919 solar eclipse expedition that proved Einstein’s General Theory of Relativity. This lens, made in the 1890s, was transferred to Herstmonceux in 1962 and installed for a while on the 13” refractor in Dome D. A second lens used during the expedition is now in this same telescope in Dome D.

There is also the Isaac Newton Dome, not included on the tour, which we could see in the distance across the main drive among the trees. This dome is now sadly empty, derelict, and closed to visitors. The Isaac Newton Telescope was finally (after a long process starting in 1947) inaugurated by HM The Queen on 1 December 1967. At the time, it was the largest telescope in Western Europe. The INT was moved in 1979 to La Palma, where it has been operating since 1984.

The Isaac Newton Dome (photo by Paul May)

After our telescope tours and a bit of shopping in the gift shop, we said our goodbyes to the OSC. Our host Sandra commented that there were lots of happy – albeit tired – smiles on the way out! Some headed straight home, and some of us went back to spend a bit more time in the Castle gardens. Then the heavens suddenly opened – and that was our sign to head home too!

Many thanks to everyone who came on this trip and made it such a fun day out, and to everyone at the Castle and the Observatory Science Centre who made us feel so welcome.

What an incredibly special place – with a fascinating history, beautiful architecture, and so many stories to tell. We all hope that the way forward with the extension of the lease is resolved soon, and that the OSC can continue doing such great work here.