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The Great Melbourne Telescope

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Matt Smith:

Welcome to a La Trobe University podcast. I would be your host Matt Smith and with me today is Dr Richard Gillespie, Head of the History and Technology Department at Museum Victoria. Thanks for joining me Richard.

Richard Gillespie:

It's a pleasure.

Matt Smith:

Now, you're here today to talk to me about the Great Melbourne Telescope, which has its summary right there in the name, by calling itself "Great". Can you tell me how you first became involved in this project and where your connections with the telescope started?

Richard Gillespie:

Well, I suppose one way in which I first got connected to it was walking through the museum's collections stores over the past fifteen years or so that I've been at the museum, and we have big stores full of wondrous objects up on big racking systems, on pallets, and I'd always go past all these parts, and there were about seventeen pallets, all with pieces of metal on them of various sorts saying "Great Melbourne Telescope", so I was aware that we had parts of the telescope, available in the collection that had been acquired back in the 1980s. So that was sort of my first introduction and intriguing interest in the telescope.

Matt Smith:

The telescope started its life in Melbourne and it was on the site of the Botanical Gardens. Can you tell me about that site and how did you first encounter that?

Richard Gillespie:

The Botanic Gardens became responsible for the former Melbourne Observatory site which is right adjacent to the gardens, in the late 1980s, early 1990s. They involved me at that stage in doing some historical work on the history of Melbourne Observatory as a whole. I also had become particularly interested in the history of the Observatory as really the largest scientific institution in Melbourne in the 19th century, certainly it was doing more scientific research than say even the University, because the University was much more of a teaching institution back then.

Matt Smith:

When did Melbourne first get the telescope? Tell me a bit about the background of the telescope itself.

Richard Gillespie:

The telescope goes back even before it came to Melbourne. It really dates back to the late 1840s, 1850s, when the first idea was developed by British astronomers of sending a telescope to the southern hemisphere to re-observe all the southern nebulae, the diffuse gaseous clouds – they weren't sure what they were, the clusters of stars and so forth – anything in the sky that wasn't just an individual identifiable star. And, well of course, from the southern hemisphere you see a different set of nebulae and stars and so forth than you can see from the northern hemisphere, especially if you go far enough south. So, John Hirschel had gone to the Cape of Good Hope in the 1830s and surveyed the southern nebulae. So the idea by the 1850s, we should go back and see if there were any changes had occurred in the nebulae by that point. So there was a discussion about doing a Great Southern Telescope, they called it. The Royal Society of London was involved in the project. They couldn't persuade the British government to fund it at that point. The British were busily involved in the Crimean War against the Russians. So the idea sort of went into abeyance, until the young Professor of Mathematics at the University of Melbourne, William Wilson, revitalised the idea and said "We can build the telescope and bring it to Melbourne". Of course Melbourne had by that time discovered gold so it was a wealthy colony, and Wilson and some of his allies he made in Melbourne, managed finally to persuade the Victorian government to pay for the telescope, to be designed and built in England, and in fact built in Dublin, and then brought to Melbourne and it finally arrived here in 1869.

Matt Smith:

Did it take a lot of persuasion to do, because I imagine back then Melbourne was really trying to promote itself – we were very much after that culture kind of standing, weren't we?

Richard Gillespie:

Gradually. Melbourne was never a convict settlement but they were certainly very conscious of that, but it's mainly a pastoral and wool settlement and then when gold was discovered of course a huge influx of people. Melbourne trebles within about three or four years in size. A lot of professionals came to the goldfields and to Victoria at that time – a lot of skilled artisans come as well. So they've got to come and try their luck on the goldfields but then they settle in Melbourne and elsewhere and say, become mechanics, so the Mechanic's Institute flourishes. There's a real sense of Victorian era self-improvement and self-education running through the colony at that time. Not surprisingly, Melbourne becomes the first place in the world to introduce the eight-hour day for example, because of the notion not just that it's eight hours work, but that you've then got time for recreation and rest as well. So it's a strong current in the community at the time. That said, though, there's still not many colonial politicians in Victoria who were interested in funding the telescope and it takes quite a lot of persuasion and in fact, it's really one politician in particular, George Verdon, who drives through the funding for the telescope. He's an amateur astronomer, he's done some work at Williamstown Observatory, he's very friendly with, and on the Board of Melbourne Observatory in the 1860s and he becomes the Treasurer of Victoria in his late twenties, and it's really George Verdon who manages to push the funding for £6,000 at the time. It's a bit hard to compare to figures today – maybe five million dollars by today's standard – he's the one who pushes it through parliament. The parliament actually collapses the week after they get that through. And they realise that they're going to have to get the order off to England. Of course this is all done by mail on ships. So they say, quick, quick, get the order off to England on the next boat out, which they do, and then a week later an order comes from the new government, saying don't proceed with the purchase of that telescope. It's too late, the order's already gone. And of course it would take six months to really countervail the order, so it's too late, the telescope's committed.

Matt Smith:

How long did it take for that order to be made, from when that happened, to when the telescope arrived in – I suppose there's a series of lots of boxes on a ship.

Richard Gillespie:

Look, it's a big telescope. You've got to remember it's the second largest telescope in the world, when it's built. And it's built by Thomas Grubb, a Dublin-based engineer. He has made telescopes previously, although it's not his main career – he's mainly an engineer to the Bank of Ireland, making note-printing machinery and so forth. And telescopes is a bit of a hobby. But he's also an extremely experienced optician and understands the way to build a latest technology telescope. He has liaised with a wealthy amateur astronomer in Central Ireland, Charles Parsons, who has built the largest telescope in the world, with a massive 72 inch diameter mirror. That's in Burr in Central Ireland, about 150 kilometres west of Dublin. It's been restored and it's still there – you can go and visit it. So Grubb designs a telescope that is really quite ground-breaking in several characteristics. It's the first large telescope to be fully steerable, it's on an equatorial mounting, which means it's on a mounting that will track the stars as the earth moves underneath the telescope. It's got a 48 inch diameter mirror. The mirror's made of metal because they couldn't make glass mirrors that big. It weighs over a ton. And the whole moving parts of the telescope weighed something like 8 tons, but it's beautifully balanced so the whole thing can be moved by one person essentially. It's got a very sophisticated for the time mirror support system, so that when the mirror shifts to different positions when the telescope is pointed to different elevations, even though the mirror is such thick metal that's probably 200 mm deep, it would flex slightly and distort the image so it has a system of triangulated levers to try and counteract that and balance the mirror as it shifted. That's a design that then continues to be used for another hundred years in telescopes.

Matt Smith:

You're describing that it's a bit like a work of art.

Richard Gillespie:

It's a work of art but it's also a piece of heavy Victorian engineering as well, so it's got lattice work tube and so forth – it's a very graceful-looking object. So it takes them about two years to build the telescope in Dublin and then it's shipped out to Melbourne and erected here. In 1869 they build a special building for it, with a roll-on, roll-off roof. It's really the first large telescope to be enclosed. That building still exists now down at the former Observatory site at the Botanic Gardens.

Matt Smith:

That's a decent amount of time. Were people in Victoria still looking forward to it then, and what sort of reception did it have when it was opened?

Richard Gillespie:

Look, there was a lot of attention in the media to it. Actually at all the stages of its manufacture too and in the British media too it became, if you think like the steamship Great Britain and the Great Eastern Railway – all the things that British engineers at the time, the public called the "Great Technologies" and the Great Melbourne Telescope fitted into this. So it got a lot of media attention, both in Britain and Ireland and Australia. I wouldn't say excitement, but a lot of interest, a lot of media …

Matt Smith:

I get the impression it might have been under-utilised a bit.

Richard Gillespie:

It had a curious career in a way. It's complicated for a number of reasons. It's got a large metal mirror and the problem with large metal mirrors is that they tended to tarnish quite quickly. It was always a problem of trying to re-polish the mirror. It was such a complex system to try and keep it not just polished, but the correct shape because it has to be the right parabolic shape to match the secondary mirror so that you're getting crystal clear images. The other reason is the whole research project was kind of problematic from the start, because what they're doing is looking through the eyepiece, on a different magnification, then trying to do hand drawings of what they're seeing of these nebulous objects in the sky. Can they resolve them into stars? Is that like a cloudy mass, a milky mass? Do I think under particular moments of particular atmospheric clarity that that actually can be resolved and that it's actually a cluster of individual stars. Until they had photography and so forth, trying to characterise, classify and define precisely what the nebulae world was an extremely difficult proposition with that technology. They were really working at the limits or past the limits of the technology. At the time the Great Melbourne Telescope is built, photography is starting to be introduced but it's not really effective for such distant astronomical objects as nebulae until really the 1870s and 1880s. So it gets used consistently for about twenty years and they do do some publications of the nebulae that they've re-observed, and compare them to how Herschel had described them forty years previously, but after about twenty years of operation the telescope has really become too tarnished and if you like, the research problem has ceased to become a research problem – there's other ways that you can start to address those issues with other types of telescope technology.

Matt Smith:

Twenty years isn't really a long amount of time for the amount of money that was spent. Considering the limitations of the technology that you spoke of, that's really quite an amazing investment considering that they knew that they would be limited in what they could do with it, and yet they still wanted to go ahead with it anyway. Was it scientific curiosity, or was it a bit of a folly? What do you think?

Richard Gillespie:

No, it was certainly scientific curiosity. I mean, what's interesting about the Great Melbourne Telescope is it was the first international telescope designed by a committee. That's now how all big telescopes get built, because how do you raise a billion dollars unless you have international communities and strategic plans where astronomers agree collectively, these are the areas we want to explore, this is the research problematic, here's the technologies we want to put on the telescope and so forth, and then have to raise the money from different sources, and governments.

Matt Smith:

Did Melbourne get more of a benefit from it, say from its prestige and from it driving scientific curiosity, than from the effects of space exploration?

Richard Gillespie:

The telescope became a kind of scientific icon of Melbourne. People would go and visit the view through the Great Melbourne Telescope, they started printing tickets and you had to book to use the telescope in the evenings. This actually started to interfere with the viewing schedule for the astronomer, but what they did was tend to book people in on moonlit nights when the moon's too bright and kind of interferes with deep space work anyway, but certainly it still occupied a lot of their time. Government House was immediately next door so it was not unusual for the Governor, or if he had a dinner party, after the port and cigars to say "Oh, let's stroll down and see if we can look at Venus, or the moon through the Great Melbourne Telescope" and there'd be a knock on the door and the observer would let in a Government House party to look through something. And in the press again it sort of became part of the scientific public culture.

Matt Smith:

So it sounds like it might have become outdated rather quickly.

Richard Gillespie:

So it really stopped being used by 1890, 21 years after it started. There are two reasons for that really. The 1890s economic depression, which means the Observatory like other sections of the public service, lose staff. But secondly, Melbourne Observatory in the late 1880s, early 1890s, is engaging in a new international project called the Astrographic Project where sixteen observatories around the world agreed to collaborate and photograph the entire sky and then produce star charts out of those photographs, because astronomical photography has become good enough to do that and in fact, they buy standard telescopes and install a telescope that's the same as the others around the world, so they know they will be getting systematic and comparable data from different parts of the sky, when they put all the data together. So that's just happening, and they decide, that's an international project that's more important than the Great Melbourne Telescope, so that's the project they keep going in the 1890s, when their staff numbers decline. And at that point too, the Great Melbourne Telescope, the mirrors are not in great condition. So it will get used occasionally. Then Melbourne Observatory closes after the Second World War, as did most of the State Observatories, because the federal government has in a sense taken on responsibility for astronomy. Mount Stromlo has already been established in the 1920s up at Canberra. When that expands after the Second World War, they say, can we get the Great Melbourne Telescope and we'll modernise it. It's got a great equatorial mounting, the basic tracking device of the telescope is still completely sound, even though it's almost a hundred years later, continue to use it. So they do, through the 1960s. They put a new glass mirror in, they start to put other motor drives and so forth on the telescope. It gets used for ten or fifteen years for quite significant work, in the Magellan Clouds, some of the big nebulae in the southern hemisphere. In the late 1980s it gets used for the MACHO Project which is probably its great claim to fame where it's completely modernised with digital cameras, the same glass mirror that had been put in in the 1960s that's used to search for evidence of dark matter.

Matt Smith:

How much of it is still the original Melbourne Telescope? Has it continuously evolved and updated to something essentially new with the same name?

Richard Gillespie:

A bit like Grandfather's Axe, yes, where everything changes except the name, yeah, the handle and the head's changed several times. The basic mounting and the builder's plates, saying "Grubb, Dublin 1868" have always remained proudly on the central cube. The main polar axis and declination axis of the telescope have been adjusted but still essentially remain the same. Bearings have been replaced, etc, etc, over time. In 2003 the Canberra bushfires swept through Mount Stromlo and completely destroyed most of the buildings and all the telescopes. And the Great Melbourne Telescope was destroyed at that time too, although incredibly what it did was strip off all the 21st century technology and left the 19th century cast iron castings that Grubb had originally built in Dublin. So in a sense the fire in a way kind of returned it back to the parts of the Great Melbourne Telescope that were still original. So, we had recovered quite a bit of the telescope in the 1980s, as those parts of the telescope were modernised and parts were discarded. So in 2008 …

Matt Smith:

So you get the rest of it here?

Richard Gillespie:

We retrieved the rest of the telescope from Mount Stromlo in 2008, working with the Australian National University, the Astronomical Society of Victoria here who'd come in on the project as well, and we brought it back with the view that we would restore it.

Matt Smith:

Yes. How much of it have you found is recoverable? Do you have to recreate a lot of it?

Richard Gillespie:

We've now done a complete analysis. We've got volunteers from the Astronomical Society of Victoria, retired engineers and opticians and so forth have been working on it fantastically, putting something like six thousand hours of work so far on the project in the last couple of years. We have now determined we have about 90% of the original telescope.

Matt Smith:

That's pretty good.

Richard Gillespie:

It's amazing. And there are some particular elements that are missing and we've started detailing those. La Trobe University is starting to assist in fabricating parts for us as well, and the Antiquarian Horological Society is remaking the clock system for us because that disappeared at some point at Stromlo. The biggest thing that we have to do is make a new mirror because the mirror from the 1960s was shattered in the bushfires. We do have one of the two original mirrors but because of the tarnishing we really want this telescope to be re-usable again as a public and educational telescope so it's pointless putting the metal mirror back in, so we're looking to either find a mirror somewhere around the world that's been decommissioned, or we'll need to commission the making of a new mirror for the telescope, a 48 inch mirror. That will be the most expensive part of the restoration project. We'll return the telescope to its 19th century glory, but we'll also embed in the telescope some 21st century technology, so we'll have a motor drive as well as hand drive, we'll have computerised controls as well as the mechanical controls of the 19th century, we'll make those concealed as much as possible so that when you come in, you'll be looking at the Great Melbourne Telescope as it was in 1869, but we'll have a whole series of functions – image intensifiers, go-to controls, computer controls, so people will be able to quickly use it for public educational purposes as well.

Matt Smith:

The ideal outcome of this is that you'd be able to go to the Botanical Gardens and that the telescope would be there in all its glory. Is that going to happen?

Richard Gillespie:

That's what we're working towards. So the Museum and the Astronomical Society of Victoria and the Botanic Gardens have formed a partnership, trying to make it feasible that we'll restore the telescope, restore the Great Melbourne Telescope House, its original building, put it back in there, and provide interpretation around it as well, so people can appreciate, not just the role of the Great Melbourne Telescope in the 19th century, but could really use it as a way of promoting the kinds of contemporary astronomy as well, especially as Australia is so significant in its contributions to astronomy now. It's a great way within an urban environment to provide a window on contemporary astronomical questions as well.

Matt Smith:

Richard Gillespie, you've got a book out now which is called The Great Melbourne Telescope and it's out from Museum Victoria's Publishing and available at all good bookstores. Thank you for your time today.

Richard Gillespie:

A pleasure.