Rebekah Higgitt uncovers Moon-mapping history
Rebekah Higgitt takes us through the Museum’s collection of globes and maps of the Moon.
Lucinda: Hi, I’m Lucinda Donnachie. Next month sees the Royal Observatory go moon mad for Spring Moon Watch, which runs from the 1st to the 5th of April. So today I thought I’d catch up with Rebekah Higgett, curator of the History and Science Technology, to talk about some of the luna globes and charts that are in the Museum’s collection.
Lucinda: So my first question, Rebekah, is when did people first start mapping the Moon?
Rebekah: Well, as long as you’ve got clear skies and good eyesight, you can do some sort of mapping whenever. So we can say it goes back to the dawn of time. Even if you’re seeing just a man in the Moon, or if you were Chinese the tradition goes that you see a rabbit, you are in a way mapping the features that you can actually see.
But it was only really possible to do this in any detail and to understand the Moon’s surface after the invention of the telescope. So we can say that mapping really goes back to 400 years ago. That’s the anniversary that 2009’s International Year of Astronomy is celebrating.
So in 1609 we know that two men used telescopes to look at the Moon’s surface. One, quite famously, was Galileo, who in December first looked at the Moon. The other was Thomas Herriot, who’s first dated drawing goes back to the 26th of July, 1609. So he beat Galileo to it, we think, although he only produced a clear composite map of the whole of the luna surface in later years than that.
Lucinda: How did Moon mapping develop after this?
Rebekah: Well, telescopes improved, of course, and knowledge was built on, so maps of the Moon could be ever more detailed and the names, shapes, positions and so on of prominent features could be agreed on among observers and astronomers.
Obviously though, however good their telescopes, observers could only ever see one side of the Moon and only ever map one side of the Moon, as the Moon only ever presents one face towards the Earth.
Lucinda: So what’s the earliest luna globe in the museum’s collection?
Rebekah: We have a fabulous rare globe from 1797 that was devised and mapped by John Russell, and it’s called the Selenographia. This, he said at the time, was the only thing of its kind that had ever yet been presented to the public. And it also of course only has one side filled in and the other is blank. But the filled-in side is based on decades of Russell’s own observations and drawings of the Moon’s surface, and it’s very beautifully done.
But what I think is particularly interesting about this model is not only its detail and its age, but also the fact that it demonstrates the relative movement of the Earth and the Moon. There is on the model a small terrestrial globe that can be used to simulate the apparent wobbling motion, or libration, of the Moon.
The motions of the Moon and the Earth like this actually mean that slightly more than half of the Moon is visible to the persistent viewer if they take observations over a long period of time.
Lucinda: What other early Moon maps do we have?
Rebekah: There are several books in the library that show early engravings of the Moon, and we also have models of the Moon that are parts of the solar system in our collection of auroraies or planetary lunaria and so on.
The next items, chronologically speaking, that show the development of luna mapping are the original sheets that we quite recently acquired of the map of the Moon produced by an amateur astronomer called H.P. Wilkins. The first edition of that came out in 1946. He was director of the British Astronomical Association’s luna section.
These maps, of course, are on a much more detailed scale than the globes. We’ve got 21.6 miles to the inch. But they are particularly interesting as being products of an age just before space travel became possible and changed absolutely everything in terms of luna mapping.
Although Wilkins was an amateur, he built upon all the photographs and drawings made by other astronomers, as well as years of his own observations. And it was in fact really the height of what was possible in Moon mapping while man was still bound on Earth.
Interestingly, Wilkins thought that there was evidence of an artificial structure on the Moon’s surface. And although it was known that there was very little, if any, atmosphere at all on the Moon, he didn’t actually discount the possibility of life on the Moon.
Lucinda: What made him think that?
Rebekah: Well, I don’t know a great deal about the story, but I know that there was an astronomer who said he thought he’s seen a structure on the Moon that he looked like a bridge. And Wilkins, as an expert, was asked to comment. There is a radio interview with him in which he says that he thinks the structure certainly was artificial, which would then suggest that there was intelligent life on the Moon.
Lucinda: What happened to Moon mapping once man went into space?
Rebekah: Weel, of course it became increasingly obvious that the Moon was in fact lifeless. But the first thing we could see happening was that all the missing details could be filled in, particularly of the course the unknown, the dark side of the Moon. And this could mapped and be put onto globes.
We have a series of globes from the 1960s and 70s that show just how fast things were changing in this period, to the extent that data could be superseded between the beginning of a globe being designed and it actually being published and available to the public.
The first satellite was in space in 1957. The first photographs of the far side of the Moon were taken in 1959. The first man in space in 1961, and man landed on the Moon in 1969. So these globes now could start filling in the blank side of the Moon, of course, but also mark things like landing positions of space probes and eventually, of course, the Apollo landings.
So our 1961 Russian globe shows the area photographed in 1959 by the Automatic Interplanetary Station, or the Luna Missions. And the 1969 Danish globe shows further Russian and American unmanned landing sites, but it’s obvious that that globe was produced, or was beginning to be produced, before the Apollo 11 landing of 20th July that year.
The 1971 globe, of course, has this information plus the Apollo 12 landing site. But basically information was coming in very thick and fast at this time, and it took a while for it to be incorporated into commercially available globes like these ones.
Lucinda: What’s the future for Moon mapping?
Rebekah: The Moon’s really been less on the agenda since those early days of space exploration, but NASA is about to launch their lunar reconnaissance orbiter, which is scheduled for launch in April. It aims to make the most detailed maps yet of the lunar surface, and also to provide information about the minerals and other natural resources and composition of the Moon.
One thing that it is planning to do is fly over the historic Apollo landing sites in order to put paid to all the conspiracy theories that have been floating around about man not actually having made it to the Moon.
Lucinda: Well, Rebekah, that’s been fascinating. Thank you.
If you’d like to take a closer look at the Moon, then come to one of the Royal Observatory’s special Spring Moon Watch events, for the chance to view it using our 28-inch telescope. Dates are at nmm.ac.uk/iya2009. And if you would like to learn more about the museum’s collections, just visit nmm.ac.uk/collections.