I took a ride on a moving radio telescope
Oh, wow. The Parkes
Telescope, here in Australia, is most famous for receiving pictures of the Apollo 11 moonwalk. But it is still in almost constant use for astronomy and scientific research. Now, today is a maintenance day here, which is why I'm allowed to be here on the surface of the plate. And the plate is about to tip over, almost all the way to the ground, and I'm going to be here while it happens. I'm going for a walk! But that would be very slow and boring images of me just standing awkwardly and sitting here while my world tilts.
While that happens, let me show you how I got here. I'm going to be filming this awkwardly. We have John here who is going to show me around. We have Jack behind the camera. Let's see a
telescope! - Yes. Let's go in, Tom, and see what it's like inside. - You can say that it was built in the 60s and 70s, right? Big asbestos warning. - This is the ground floor where we have the air conditioning units that help keep all our electronics cool. - And astronomers, presumably! - And astronomers too. Right behind Jack here, we have the most important room in the building, which is the astronomer's kitchen.
If they visit, they can stay on the site. But over the last 10 years, we've moved to a remote observing regime where people can log on over the Internet to observe. So we have fewer and fewer astronomers visiting now. But let's go upstairs and take a look at the main control room. So follow me up. - This is so weird, because... the clouds are spinning! I know the platter is spinning, but I can't see anything. - So, this is the old control room. The old control table that was recreated for the movie The Dish used to be located there.
But in 1982, it was decommissioned and replaced by a computerized desktop that used the PDP-11 computers. It doesn't crash very often, because it doesn't have an operating system. It just maintains itself very reliably. And so we still use it to drive the dish around and aim the
telescope as well. If it ain't broke, we ain't fixing it! The
radio waves coming down from the stars, are reflected by the parabolic surface of the dish, and are brought to the focus where the
radio waves are concentrated. Typically, we can collect a few terabytes of data a day, but with the new receivers we're going to put into operation later this year, we'll see maybe nine terabytes an hour.
telescope itself is an extremely sensitive
radio detector, because the energies we are collecting from the stars are incredibly weak. If I were to release the plume and let it slowly drift to the ground here like this, the energy that the plume expended when it hit the ground was more than all the energy ever gathered by every
telescope ever built, in terms of astronomical data. And that's why
telescopes have to be so big, because you want as big a collection area as possible. Any electronic device will transmit
radio waves that could very easily overwhelm the really weak signals we're trying to detect, like cell phones- - By the way, like these wireless microphones!
It's a maintenance day. I have special permission for these! - That's how it is. A lot of this technology here we've designed ourselves, but we also have other equipment that we buy off the shelf, and then we have to put it in shielded cabinets, because it's not really designed to be
radio silent, so to speak. A mobile phone on the surface of the moon, 400,000 kilometers away, would be one of the brightest
radio sources in the sky for us. So if we can detect it from the moon, we have no problem detecting it from the parking lot!
We refer to this as the master control panel. If I were to turn this off here, you can see it's on the remote, it's going to be on the computer control so people offsite can log in, take over, and move the
telescope. But if I were to put it in local and master control, I would be able to move it using these dials, up and down, left and right. - Wait, the dials still work? - Oh yeah. Ah OK. Gravity is changing direction. I... We have to walk around here. I guess we have to stay horizontal here.
I'm actually not sure whichhorizontal is more. Am I still...? No, I think I need to go further. I'm not horizontal yet. I have no frame of reference. I can't see the horizon. I can't see anything. This is dizzying! - Because we observe remotely now, often, there is no one in the tower when we are observing. And so we need a way to make sure the
telescope is secure at all times. So we have this device called the
Telescope Protection System or TPS, which monitors hundreds of data points on the
telescope. And if it detects a problem that could be a problem, it immediately alerts us via SMS, email, telex, everything.
And we can immediately go down in the
telescope, see what's wrong, and fix it. And we have an anemometer, as soon as the wind hits a certain critical speed, that's when we say, the winds are too strong and we just put the
telescope away. Because essentially, the
telescope is just a giant beach umbrella. - I mean, this thing is incredibly robust. Holds up to significant wind and weather. - When commissioned in October 1961, it was only intended to run for 20 years. So now we are 41 years old. About that. And the reason for that is because we have continually upgraded the
The most obvious upgrades have been to the surface of the dish. - I'm not going to do anything, but I... suddenly, I'm not walking on the solid surface, I'm walking on the mesh of the plate, and my brain is... Is it just trying to deal with it? - Let's go up to the surface of the plate here. So first we're going to go up through the spiral- - Spiral staircase! -spiral staircase in the central column This central column is on a foundation separated from the rest of the building, because at the top of this column is the equatorial master, the device that helps us point the
So we don't want it to be connected to the rest of the building because the vibrations will cause the tips of the
telescope to be out. So go up. - So all the cables here are transmission cables? - That's right. Yes, they are bringing signals from the focus booth, and also, we send other commands to operate the equipment and power it, and so on. Well. - I just looked and suddenly there is a horizon! - Now we are going to pass the door to the azimuth track. - Right. Well. Oh yeah. I just looked up. There's a
telescope up there! - Before we go all the way down, you can see that this is the tornado room.
The cables coming down from the focus booth go down here first. There are two rings that rotate in the opposite direction. As the platter rotates in azimuth, they rotate in the opposite direction, so they take the slack and release, so the wires don't get caught twisted and tangled or something like that. - Oh, that's very clever. - So this level is what you call the azimuth track, and this is the actual azimuth track. And if you look here, you can see that it's sitting on four rollers, but only two are driven. On this track, we move it left and right like this.
But you can see in the center there, there's actually nothing holding it down. It's just rotated there. It is only the weight of the structure that keeps the
telescope grounded. - Because everything from this level onwards weighs a thousand tons or the equivalent of three fully loaded jumbo jets. - Yes, okay! Everything's fine. - So when they built the
telescope in the 1950s, they didn't have computers that could do coordinate conversions fast enough. So instead, Barnes Wallis, a very famous British engineer, came up with this device, essentially said it's an optical
telescope. And since that's the polar axis, once you point the optical
telescope at whatever position you want in the sky, you just have to move it at a constant rate around the polar axis so that you can then follow the object smoothly across the sky. - You are adjusting to the earth's rotation simply by turning something at the same angle in the opposite direction. - In the opposite direction.
And this was the secret to the success of the
telescope, we were able to point the
telescope very, very accurately in the sky. In fact, it was so successful that all subsequent large, single-dish antennas employed an equatorial master until about the 1990s, when microprocessors were small and fast enough to do coordinate conversions on the fly. Before we go up, let's take a little tour of the superstructure just below the dish. So here we go. - You're walking around here much more casually than me! - Ah OK! You can see here, this is a great view. You can see to the east where we have the Hervey Ranges which protect us from the
radio emissions from the larger population centers further east. - Right. - This is one of the reasons why he was chosen.
It's very quiet. - All good. Then, next stop... - Yes.- Surface. We'll go around. We'll keep going around, and then we'll end where we started. - If you just turn the camera around for a moment, that's where I was standing a moment ago, I was in the middle of that plate. This walk I'm taking is not just a trick. It's called a "hay
ride" sometimes, but it turns out it's a term the Americans invented for a movie that was shot here over 20 years ago. The Parkes folks really just call this "mounting the plate," and use it to get heavy equipment in and out of the center. because it's so much easier to let the platform do the lifting instead of actually trying to lug bulky gear through all the hallways and stairwells indoors.
Two hands on the rail... and we're down! Thank you very much, people! Thanks Jack!