I’ve just been writing up the report of our recent trip to Herstmonceux, and have been reminded that many people on the trip were not aware of the Christie Enclosure in Greenwich Park where, in particular, the 36-inch Yapp Reflector was installed.
I thought I’d write a little post on what I know about this, apparently little-known, area of Greenwich Park.
This area of Greenwich Park was originally enclosed in 1899, when William Christie was the Astronomer Royal (hence, of course, the name). It was around 350 yards to the east of the current ROG site, and originally housed the Magnetic Pavilion. This replaced the magnetic observatory built by Airy in 1836-7 in an area just south of today’s Altazimuth Pavilion, around the area of the planetarium dome. However, when the South Building was erected in 1891, it became clear that the iron and steel used in the new building was affecting measurements, so the new Magnetic Pavilion was built away from the disturbing effects of these buildings. A photograph of the Magnetic Pavilion in the newly enclosed Christie Enclosure is below:
In 1931/2, this building was demolished to make way for buildings for the Yapp telescope, the Reversible Transit Circle and the Cookson telescope. You can see a complete plan of the enclosure in this map:
The Yapp telescope was installed in 1932, beginning observations in 1934, and was used primarily for the measurement of the colour temperatures of stars using a spectroscope. The Yapp Dome in Greenwich Park can be seen in this picture:
A picture of the telescope in-situ in the dome in Greenwich Park is here (note the spectroscope mounted on the back):
I’ve searched for some aerial photographs of Greenwich Park during this period, just to put the buildings in their context. I can only find an old German WWII reconnaissance photo of Greenwich! The Christie Enclosure is clearly visible in the bottom-right quarter of the photograph:
Fascinating to see from the aerial photo that the Christie Enclosure was almost half the area of the main site.
Anyway, hopefully that answers some of the questions that people had about the Christie Enclosure. Feel free to ask any more questions that you may have here… I may not have all the answers, but I probably know someone who does!
Well, after writing that I couldn’t find any aerial photographs of Greenwich Park which picture the Christie Enclosure, I became aware of the “Britain from Above” website today.
Two pictures are on this site of the Royal Observatory in 1948 and both show the Christie Enclosure:
I’ve highlighted the Christie Enclosure in both images with a green circle.
Interesting that the WW2 allotments that were situated in Queen’s Field (between the ROG and the NMM – where the Olympic Stadium was built) are still just about visible in the bottom left hand corner of both images.
Great to see Greenwich park as it would have been back then. The aerial photos really put it into perspective. The Christie Enclosure was a lot further away than the main site – this surprises me.
Remember, the site was selected so that there should be no magnetic disturbance from iron in the neighbourhood, which was the problem after the South Building had been constructed.
However, I’ve learnt a little more about the choice of site. It was in 1895 that the Admiralty proposed to move the Magnetic Observatory to a new site within the Park. The original plan was to establish the Observatory on a site immediately to the east of Blackheath Avenue (just over the road from the main site) but, after much procrastination, a location further east was selected. This move further east, I understand, was due to extended negotiations with the park authorities. There seem to have been continual battles between the RGO and the park around boundary lines ever since the observatory was completed in 1675!
The Magnetic Pavilion building was completed in 1898, and the Magnetic Observatory became operational the following year. However, the public record office shows that, due to a reduction in Admiralty expenditure, there had been some forced departures from the original design, with the result that (quote) ‘a building with a very unsightly roof now disfigures that portion of the Park‘.
It doesn’t look too bad in the photo in my first post, but it is clearly not as ornate as originally intended!
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