Oh, wow.
The Parkes radio telescope, here in Australia,
is most famous for receiving pictures from the Apollo 11 moonwalk.
But it's still in near-constant use for astronomy and scientific research.
Now, it's a maintenance day here today,
which is why I'm allowed to be here on the surface of the dish.
And the dish is about to tilt over,
nearly all the way to touching the ground,
and I'm going to be here while it happens.
I'm going for a ride!
But that would be a lot of very slow, boring footage
of me just awkwardly standing and sitting here
as my world tilts over.
So while that's happening,
let me show you how I got here.
I'm going to be filming this awkwardly.
We've got John here who's going to show me around.
We've got Jack behind the camera.
Let's go see a telescope!
- Yeah. Let's go in, Tom, and see what it's like inside it.
- You can tell it was built in the '60s and '70s, can't you?
Big asbestos warning.
- This is the ground floor where we have the air conditioning units
that help keep all our electronics cool.
- And the astronomers, presumably!
- And the astronomers too.
Just behind Jack here,
we have the most important room in the building,
which is the astronomer's kitchen.
If they do visit, they can stay on site.
But over the last 10 years,
we've switched to a remote observing regime
where people can log in over the internet to observe.
So we have fewer and fewer astronomers visiting now.
But let's go on upstairs
and have a look in the main control room.
So, follow me on up.
[warning siren]
- This is so weird, because...
the clouds are rotating!
I know the dish is rotating, but I cannot see anything.
- So, this is the old control room.
The old control desk that was recreated for the film, The Dish,
used to be located about there.
But in 1982, it was decommissioned and replaced by a computerized desk
that used the PDP-11 computers.
It doesn't crash very often,
because it doesn't have an operating system.
It just stays up very reliably.
And so we still use it to drive the dish around
and to point the telescope too.
If it's not broken, we're not fixing it!
The radio waves coming down from the stars,
they're reflected off the parabolic surface of the dish,
and they're brought to the focus
where the radio waves are concentrated.
We can typically collect a few terabytes of data a day,
but with the new receivers that we're commissioning later this year,
we'll be looking at maybe nine terabytes an hour.
The telescope itself is an extremely sensitive radio detector,
because the energies that we're collecting from the stars
are incredibly weak.
If I was to release the feather
and let it slowly just drift to the floor here like this,
the energy that feather expended when it struck the floor was more
than all the energy ever collected by every radio telescope ever built,
in terms of the astronomical data.
And so that's why radio telescopes have to be so large,
because you want as large a collecting area as possible.
Any electronic devices will transmit radio waves that could very easily
overwhelm the really feeble signals we're trying to detect,
such as mobile phones-
- Such as these wireless mics, by the way!
It's a maintenance day. I got special permission for these!
- That's right. A lot of this tech here we've designed ourselves,
but we also have other equipment that we buy off the shelf,
and then we have to put them in shielded cabinets,
because they're not really designed to be radio-quiet, so to speak.
A mobile telephone on the moon's surface, 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 trouble detecting it from the car park!
We refer to this as the master control panel.
If I was to turn this off here, you can see it's on remote,
it'll be on computer control so that people off-site can log in,
take control, and move the telescope.
But if I was to put it onto local and master control,
I'll be able to move it using these dials, up and down, left and right.
- Wait, the dials still work?
- Oh, yeah.
[warning siren]
Oh, okay. Gravity is changing direction.
I-- We got to walk this way.
I guess we got to stay horizontal here.
I'm not actually sure what horizontal is anymore.
Am I still...?
No, I think I need to go further.
I'm not horizontal yet.
I've got no reference frame. I can't see the horizon.
I can't see anything. This is dizzying!
- Because we observe remotely now, often,
there's nobody in the tower when we're observing.
And so we need a way to make sure the telescope's safe 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 an issue that might be a problem,
it immediately alerts us
using SMS messages, emails, telex, everything.
And we can immediately descend on the telescope,
see what's wrong, and fix it.
And we have an anemometer,
as soon as the wind reaches a certain critical speed,
that's when we say, the winds are too high,
and we just stow the telescope.
Because essentially, the telescope's just a giant beach umbrella.
- I mean, this thing's incredibly robust.
It's held up to significant wind and weather.
- When it was commissioned back in October 1961,
it was only intended to operate for 20 years.
So we're now 41 years over that.
And the reason for it is because we've continually upgraded the telescope.
The most obvious upgrades have been to the dish surface.
- 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 dish,
and my brain is... just about dealing with it?
- We're going up into the dish surface here.
So we're first going up through the spiral-
- Spiral staircase!
-spiral staircase in the central column.
This central column is on a separate foundation
to the rest of the building,
because at the top of this column is the master equatorial,
the device that helps us point the telescope accurately.
So we don't want that connected to the rest of the building
because the vibrations will cause the pointings of the telescope to be out.
So come on up.
- So all the cables here are transmission cables?
- That's right. Yeah, they're bringing signals
down from the focus cabin, and also,
we send other commands up to operate the equipment and power it, and so on.
Okay.
- I just looked over and there's a horizon all of a sudden!
- We're now going to go through the door down to the azimuth track.
- Right. Okay. Oh, yeah. I just looked up.
There's a telescope up there!
- Before we go all the way down, you can see this is the twister room.
The cables coming down from the focus cabin come down here first.
There are two counter-rotating rings.
So as the dish rotates in azimuth, they counter-rotate,
so they take up the slack and release it,
so that the cables don't get twisted and tangled or anything like that.
- Oh, that's very clever.
- So this level is what we call the azimuth track,
and this is the actual azimuth track.
And if you look here,
you can see 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 nothing actually holding it down.
It's just pivoted there.
It's just the sheer weight of the structure that keeps the telescope grounded.
- Because everything from this level on up weighs a thousand tonnes
or the equivalent of three fully-laden jumbo jets.
- Yeah, okay!
All right.
- So when they built the telescope back in the '50s,
they didn't have computers that could do the coordinate conversions fast enough.
So instead, Barnes Wallis, a really famous British engineer,
he came up with this device, essentially said it's an optical telescope.
And because that's the polar axis,
once you point the optical telescope to the position you want on the sky,
you only have to move it at a constant rate around the polar axis
so that you could then follow the object
smoothly across the sky.
- You're adjusting for the earth's rotation by just rotating something
at the same angle in the opposite direction.
- In the opposite direction.
And this was the secret to the telescope's success,
we were able to point the telescope
very, very accurately on the sky. In fact, it was so successful
that all subsequent large, single-dish antennas
employed a master equatorial up until about the 1990s,
when the microprocessors were small enough and fast enough
to do the coordinate conversions on the fly.
Before we go up, let's have a little walk
around the super structure just under the dish.
So, here we go.
- You're walking around here a lot more casually than I am!
- Oh, okay!
You can see here, this is a great view.
You can see out towards the east where we have the Hervey Ranges
that shield us from the radio emissions
from the larger population centers further east.
- Right.
- This is one of the reasons why it was chosen.
It's very radio-quiet.
- All right. So, next stop...
- Yeah. - Surface.
We'll go around. We'll keep going around,
and then we'll end up where we started.
- If you just turn the camera around that way for a moment,
that's where I was standing a moment ago,
was in the middle of that dish.
This ride I'm taking isn't just a gimmick.
It's called a "hayride" sometimes,
but it turns out that's a term that was invented by Americans
for a film that was shot here more than 20 years ago.
The folks at Parkes actually just call this "riding the dish",
and they use it to get heavy equipment
in and out of the central part.
Because it's a lot easier to let the dish do the lifting
instead of trying to actually lug bulky gear
through all the corridors and stairwells inside.
Two hands on the railing...
and we're down!
Thank you very much, folks!
Thank you, Jack!