Natasha: Hello. I’m Natasha Waterson, and today I’ve come to the Royal Observatory’s Astronomy Photographer of the Year exhibition. But I’m not here to see all the amazing contemporary photographs on show; I’m here to discover more about the important scientific photography work that was once carried out by astronomers here, when the ROG was still a working observatory. To tell the story, I’m joined by Becky Higgitt, the Royal Observatory’s Curator of the History of Science. Hi Becky.
Natasha: So, Becky, what sort of work are we talking about here, and when was it going on?
Becky: Well, photographic work really started at Greenwich from the 1870s when the then Astronomer Royal, George Airy, was convinced to start a new department, which was called the Photographic and Spectroscopic Department. And he also got funding to have a new assistant who would head it, who was E. Walter Maunder. It’s still quite a new technology at this date, both photography and spectroscopy, previously something only really that amateur pioneers were working on; people who had private money of their own or private funding from elsewhere.
So there’s four main areas of activity at Greenwich, really. One is the decision to take a daily or sometimes twice-daily photograph of the Sun’s surface to study changes in sunspot activity. Another area was the use of photography during astronomical expeditions, particularly to photograph the Sun in eclipse to look at the corona, and also during Transit of Venus expeditions.
Another area was the involvement of the Observatory from the 1880s with an international project for doing a photographic map of the whole sky, which was known as the Carte du Ciel project. And then there was also a low level of more speculative work being done, particularly with a large 30-inch photographic equatorial telescope that they had from the 1890s.
Natasha: And am I right in thinking that some of the work was done in this building?
Becky: Yes. That last telescope that I mentioned was actually in the dome on the top of this building, and also a photoheliograph of photographing the Sun was mounted there, too, in the dome. In the floor below that — so that’s the top floor — there were also dark rooms, stores for all the plates and that kind of thing. The next floor down, the main floor, there were also all the computers and people who actually studied and measured and recorded all the data that they could get from the plates themselves.
Natasha: Did the scientists make any exciting discoveries?
Becky: Well, the Royal Observatory is not usually connected with exciting discoveries and speculative research. That wasn’t the kind of thing that Government, particularly in the 19th century, was particularly interested in funding, although they were beginning to change their attitude. But there was some coming out of photographic work, being such a novelty for the time. So one of the main ones, probably, is from the study of sunspots, where they were able to prove the regularity of that cycle and the changes in the positions of sunspots and so on, and also able to demonstrate quite fully the relationship between different kinds of magnetic activity that occurred on Earth and the sunspot positions.
There was also the possibility of long exposure photography, which allowed the discovery of new, very faint bodies that you couldn’t see with a normal telescope and the human eye. So probably the main example of that is from 1908 when the eighth moon of Jupiter was discovered here, with a photograph taken with the large equatorial telescope on top of this building.
And then, also, eclipse expeditions. Perhaps most famously from 1919 were some expeditions that were carried out with the main purpose of trying to provide observational proof of Einstein’s theory of relativity. And the photographs that they brought back from those expeditions did convince a lot of people of the worth of that theory.
Natasha: So when the Observatory closed, what happened to all the kit?
Becky: Well, the Observatory closed in Greenwich in the 1950s after the Second World War, and it moved to Herstmonceux in Sussex in the 1980s, and then moved to Cambridge. So things have been shifted a lot. But some of the equipment, for example that large 30-inch telescope I was talking about, that still can be seen at Herstmonceux today in their science centre. But lots of the other bits of kit, the smaller plate measuring devices and so on, photoheliographs, came back here, so we have them in store, mainly. And all the photographic plates that they took are in-store elsewhere in London.
Natasha: Is there anything that visitors here can actually see today?
Becky: Yes. There is, one of the photoheliographs that’s recently been restored and is on display in our Altazimuth pavilion. It’s not always open to the public, but we hope that there will be lots of opportunities next year from January to May, which will coincide with the next exhibition that we’ll be having in this space, which is on the Sun. It will be called, The Sun: Fire in the Sky. And it’s about the physics of the Sun and its effects on the Earth, and so on, and looking at how this has been observed through history and how our knowledge has developed. Then, also including, of course, some of that stuff I was saying about the Royal Observatory’s important role in solar observation.
Natasha: Becky, thanks very much.