Telescopes are really very simple things. They collect light. They work in a way a bit
like the human eye. And you can imagine a telescope as a giant eye. The bigger the telescope,
the more light it can collect and the further it can see. And it really is just as simple
as that. So if you could build a very big telescope, you can see very faint sources,
and you can see very distant sources. Sources at the very edge of the Universe. Things from
which the light has taken over 12 billion years to get to us. SALT is the Southern African Large Telescope. It’s the biggest single optical infrared
telescope in the Southern Hemisphere. And I think what’s so important about the project
is that it is an international collaboration. It allows us to work with people from the
United States, from Europe, from India, and to bring those resources together to study
the exciting things you can only see from the Southern Hemisphere.
For people like me, who love our continent, SALT could be a focal point for development
of scientific research in the continent, the African continent. Because we have this fantastic
first-world, first-class facility that can attract astronomers and people who want to
do astronomy in the whole African continent or just in South Africa.
SALT is built in Sutherland. And the location was chosen because there was already another
observatory existing there. Therefore, there was also infrastructure there. I mean, you
didn’t have to go and start building an observatory from scratch. OK, home in back again to 240, please. Nicola (?), we’ll move to 240. This is the heart of the telescope, the primary mirror array, which consists of 91 individual
mirror segments in a spherical configuration. This is equivalent to a mirror that would
be 11 meters by 10 meters in size. Building something 11 meters in size is just, at the
moment, technically impossible. So instead, we’ve made it up from a mosaic of individual
segments that collect the light and focus it up to the instrument at the top of the
telescope. At the moment, we have two science instruments
on the telescope. One of them is an imaging camera—very similar to a video camera—which
is used to make observations of varying phenomena, where the light is varying for one reason
or another, possibly on quite short time scales. So this camera can take up to 10 frames a
second. And so for things that are rapidly varying, that’s an ideal sort of instrument.
The other instrument is a spectrograph, which splits up the light into component colors
and then analyzes what we call the spectra of an object. And so, with that instrument,
you’re able to probe a lot of detail and get a lot of physics out by looking at galaxies
and stars and so on. In any given night, we will be observing many
different objects from many different programs, which is quite different to the normal, classical
way of scheduling telescopes, where an astronomer might get a telescope to themselves for one
or two nights. OK, that should bring it to focus.
All right, track time, hour and a half. Going straight through the central supply rate,
[indistinct]. All right, SALTICAM is back on track. Say, half an hour from now, extending
45 minutes from that time on. I query the database, and it gives me several programs
which are visible at that time. In this case, it’s only two targets. One is looking at
galaxies from our Israeli collaborators. And there’s another target looking for Kuiper
Belt objects. These are small bodies, celestial bodies on the outskirts of the Solar System.
So we use SALT for science from, in astronomy, basically from one end to the other. We can
look to the very, very distant Universe, and we can look at stars in our own galaxy. But
then there are programs also which look at objects inside our own Solar System. Here’s
an example of an observation we made recently of asteroids. These were 10-second exposures.
See the asteroid moving over here? So every frame is one SALTICAM frame from the telescope.
And we just put it together, and you see the object moving over there.
There’s been a lot of science which has hinged around having this camera, that could
take very, very fast observations. And then with the spectrograph, we were able to do
quite a lot of very interesting observations of some colliding galaxies.
One bit of research which we just recently finished was a galaxy we’ve been calling
the “Bird Galaxy” because it looks like one. There was a surprise that the whole thing
was supposed to be only two galaxies. But for the first time, really resolved, this—what
we call the head of the bird—it really is a galaxy of its own. Everything which is blue
over here is new stars being born. And on the other hand, the red bits are very obscured
regions. There’s a lot of dust inside. So with SALT, what we did, we got a spectrum,
the bright things are actually emission lines. This is actually hydrogen. And these two are
nitrogen lines. And further on, you see sulfur. And then was sodium, and oxygen, and all those.
They are twisted. Means that their velocities are different. So this part of the spectrum
is actually moving away from us. And this part of the spectrum, well, it’s coming
towards us. So when you map now this structure, on the image what we have, you can build an
understanding of how this thing is moving. The Universe is a very dynamic place. Everything
is moving with respect to everything else. And it’s very useful to have a tool to measure
that movement. As an astronomer, it’s fantastic because
I have now access to one of the largest telescopes in the world. So the type of science that
I can do is just so much increased. It’s just so many possibilities.
SALT is a focal point for development of science, research, and technology in South Africa.
With SALT, we can motivate young people to want to take up careers in science. And with
SALT, we will be able to come up with exciting discoveries that, you know, they give people
a good feeling. You know, when you know that there’s some good things happening in your