April 2, 2017

Altazimuth Pavilion and Endeavour Room Tours – 25th March 2017

Report by: Mike Dryland

On Saturday March 25th we ran tours of the Altazimuth Pavilion (‘Altaz’) and Endeavour Room at the ROG so Flamsteed members could see these interesting spaces which are not open to the public. The tours were a try-out both to see if members were interested in this type of weekend event, and to see if the combination of locations offered a good tour experience.

The tours worked well on both counts. We were able to offer four tours each for about 10 members. All the tours were well attended. Each tour lasted an hour and they were led by Mike Dryland and Grey Lipley alternately.

Both spaces have interesting histories. The Altaz was opened in 1896 to house Christie’s Altazimuth Telescope which remained in use there until 1940 when it was scrapped. In October 1940 during WW2 the building was badly damaged by bombing. After the war there was a move to demolish the Pavilion, but fortunately it was restored, and from 1963 to 1982 housed a large (6.7 in) equatorial refractor, the Sheepshanks refractor.

In 1982 the Dallmeyer Photoheliograph and Newbegin refractor were returned from the solar department at Herstmonceux and mounted in the Altaz in place of the Sheepshanks which was put in the RMG store. The Dallmeyer and Newbigin are still in the Altaz. The observing platform was reconstructed during the major renovation 2004-7, but a combination of safety issues inside the dome and maintenance problems with water ingress, mean the dome area is closed to the public.

Flamsteed members were delighted to see these historic instruments and looked forward to a time when they might be put back in use. There were many questions and much discussion about how the instruments were operated and if they could be used now.

The Endeavour Room is now a seminar room and library which occupies the Lassell Dome atop the ROG South Building (now the Astronomy Centre). The South Building, or ‘New Physical Observatory’ as it was then called, was built between 1891 and 1899 to house new departments working on astrophysics.

The dome on top of the South Building was originally located at ground level where the South Building now stands. It then housed the Lassell 2-ft reflector donated to the ROG in 1883. The reflector was scrapped and the dome moved to its present position in 1897 as a home for the Thompson telescopes – a 26-in photo-refractor and a 30-in reflector donated by surgeon Sir Henry Thompson. The Thompsons shared a single mounting which rather limited their use. When the Observatory left Greenwich in the late-1950s the Thompsons were moved to Herstmonceux where they can be seen today, now in separate domes.

After the National Maritime Museum took control of the buildings the money was eventually found to convert the dome into a planetarium equipped with a Spitz projector. The Caird Planetarium opened in January 1965 and gave sterling service until September 2004 because it was being replaced by the new and much larger Peter Harrison Planetarium. The much-loved Spitz projector was transferred to the James Lockyer Planetarium in Sidmouth Devon, and the dome was converted to its present state, the Endeavour Room.

Visitors are always impressed by the Endeavour Room today, and we were also able to display photographs showing how it appeared housing the Thompsons and then the Caird Planetarium.

The weather was splendid for the event and we received much positive feedback.