Awesome Astronomy - The Nancy Grace Roman Space Telescope

Welcome to AstroCamp

0:00It's the 365 Days of Astronomy podcast, coming in 3, 2, 1.

0:30Hello, hello, and welcome to AstroCamp for September 2026.

0:36I'm Jenny. I am one of the organisers for AstroCamp. We've also got Paul and John as well. Unfortunately, Damien can't be here this time, so you just got to make do with us three. So, a little reminder about the programme of events, which are all included in the ticket prize. It's up to you whether you want to come to them or not. So, I'm kicking us off today with a talk about the Nancy Grace Roman Space Telescope.

1:08It just gives you all something to have a little chat around the scopes. Maybe not tonight, but tomorrow night, yeah. So, on events where we do have a little bit of rain, you'll often find people in the evening congregating underneath here. So, you know, the common is not just for observing. You're more than welcome to set your telescopes up in this area here, which is what we refer to as the common. Everyone sort of observes together. If it is poor weather, we will quite often just come and sit underneath here with our red lights, and then we just chit-chat about all sorts of things, really.

1:40So, you know, don't feel like you have to hide away if it's poor weather. So, we've got me now today. Then tomorrow is like our big activity day. So, we have our main talk, which is being given by Kath. Kath, stick your hand up. So, Kath is going to talk to us all about smart scopes. So, I think that's going to be something that many people will be interested in. Following that, then, we have the legendary AstroCab quiz.

2:07It's a good one. It's a good one. Yeah. The music round's back. Well, hey. The music round not done by me. And a gram round. Oh. And the ding-bats are back. Hey!

2:23That's rude to talk about your audience. Yeah.

2:28You also have your caption competition as well. So, forms have gone out around and about, but there's more forms down here. The box for entries is down here. Get those entries in by Sunday night, because then on Monday, that's when we'll be judging them. We'll be announcing the winners at the afternoon tea on the Common. And then, after afternoon tea on the Common, we have got the Awesome Astronomy Bonanza. Oh, we do, because it's not just me and you here this time, Paul. I'm not here, Monday. Yeah, I know. You're not here. But someone else is, from Team Awesome Astronomy.

3:01So, if you listen to the podcast, there is a secret sauce to the podcast recipe. It's the dark, yeah. I think it's the dark matter. Yeah, he is, he is. He's the dark matter of Awesome Astronomy. He holds us together, but no one ever sees him, right? And this is Dustin. He may not exist. Yeah. So, Dustin, just wave. This is Dustin. Dustin is our editor, and he has actually come all the way over from New Hampshire. So, I'm roping him in to do the panel bonanza with me. Yeah. So, we will be doing that after afternoon tea.

3:35What the panel bonanza is, bring your spacey questions, anything that you're wondering about that's going on in the night sky that's launched, that your missions are happening, concepts, what the future of space is, whatever. And we'll try and do our best to answer your questions. So, we'll also have tours of the night sky at the beginning of the night if the weather is clear. And so, we'll do a little laser pen tour. Yeah, I know. I did say if. I said if. I'll try. I'll try. Yeah.

Nancy Grace Roman Space Telescope

4:04So, okay. So, are we ready for a primer on the Nancy Grace Roman Space Telescope? Yes? Yes. Okay. So, the Nancy Grace Roman Space Telescope. It is NASA's next flagship observatory. It's just launched. Just a couple of weeks ago. And it is going to provide us with an atlas of near-infrared universe. So, it is completely different to the other infrared telescopes that we have out there. Astonishingly, it will give us maps with the same resolution as Hubble, but it's able

4:39to do this with a field of view that is 100 times greater, even though it's got the same size mirror as Hubble. Like, the engineering behind this telescope is truly astonishing. And we're going to dig into that a little bit, see. So, it's got a five-year primary mission with the option to extend it then for an additional five years. That's the hope. That's the goal. It depends on how much fuel it's got. So, we'll talk about that a little bit later on. And during its five-year primary mission, it is expected to map the distribution of a billion

5:12galaxies. Think about a billion galaxies stretching back through most of cosmic history. So, back to about 10 billion years ago. So, four-ish billion years after the Big Bang, it'll be catching a billion galaxies and telling us where they are in time and space. It's a five-year mission to seek out strange new worlds. Yeah. Well, yes, it does have a five-year mission to seek out strange new worlds. Because on top of this billion galaxies that it's expected to find, it is going to find

5:44100,000 exoplanets. We know of about 6,000 at the minute. And in those five years, this is expected to find 100,000. So, it's truly going to be a giant in astronomy, just like its namesake. And while it's mapping the position of all these galaxies, the point of it is to help us try and understand what mysterious dark matter and dark energy actually are.

Life and Legacy of Nancy Grace Roman

6:13So, I think if we're going to talk about a telescope named after a person, we should talk about that person first. So, who was Nancy Grace Roman? So, Nancy Grace Roman, I'm going to refer to her as Roman as we're carrying on. She's often called the mother of Hubble. But she was so much more than that. She was NASA's first chief astronomer. Not first female chief astronomer. The first chief astronomer. The role was hers.

6:43It was made for her. She was the driving force between creating space-based observatories. Without her pushing for it, they wouldn't have happened. Astronomers were like, no, we don't want to go to space. Not space exploration and rockets. That's not our jam. But she knew that it could open the universe to us in ways unimagined at the time. And she was the one who made it happen. And she is really the one who founded NASA's absolutely thriving astronomy workforce.

7:15Now, it's all because of her. So, she was born in Tennessee way back in 1925. She didn't unfortunately die a few years ago, so didn't see the telescope launch. But she did manage to see, you know, all of the wonders of Hubble, for example. Her mother was a music teacher. Her father was a scientist. But it was actually her mother who got her interest in the night sky. It was her mum who used to take her out, not only on nature walks, but also take her out at night to show her things like the aurora when there was a particularly strong storm

7:47and it came that far down, and show her the constellations in the night sky. So, despite her father being the scientist, it was actually her mother who got her into space. When she was about 11, she formed an astronomy club in her local school. And they used atlases and charts, books from the libraries. And they started learning the constellations, looking up at the sky, you know, when they were sort of allowed to, when it wasn't too late. And she did this for a couple of years. And then she knew astronomy was for her.

8:18That's what she wanted to do. But this is a time, you know, we're talking the 1930s, 40s, 50s, when she's going through education, where women in science was not really a thing. They faced barriers at every turn. So, even when she was in school, her teachers scoffed, because instead of taking Latin, she wanted to do algebra. And they were like, no, no, no, you're a girl. Girls don't do algebra. Girls do Latin. So, even then, at the lower levels, she was sort of facing barriers.

8:49The highest compliment she got was from one of her teachers saying, oh, you might be an okay physicist. That was the best thing that was said to her. So, she really had to overcome a lot. She went to Swarthmore College in 1946 to do her bachelor's. And she was working under Peter Van Zerkamp doing astrometry. So, astrometry is mapping the positions of stars, seeing how they change as our perspective changes as we orbit the sun.

9:19So, it's using things like parallax. So, we can do a bit of an experiment in parallax. So, stick your fingers out. Yes, that's it. Okay. Then, find something in the distance to focus on, like one of the tabs on the roof or perhaps a tree, something like that. And then close one eye and then close your other one. And you'll see that your finger appears to jump, yeah? So, this is like Earth being on one side of our orbit. Six months later, we're on another side of our orbit. We get a different perspective.

9:50And depending on how much shifting we see with stars' positions in the sky, we can then work out their distance. So, this is what she was working on at the time. Peter Van Zerkamp was well known for this. In fact, he even predicted the existence of a planet around Barnard's star way back in the 1960s because of astrometry. Turned out not to be true, but later using other methods, we did find a planet around Barnard's star. So, then 1949, she went off to the University of Chicago to do her doctorate.

10:20And she was working on the Earth's major moving group. So, this is a bunch of stars which are moving through space together. Some of those stars make up the plough. So, this is their projected motion in the past and then in the future. So, you can see the plough shape pop up and then it'll disappear. So, she was working on mapping their positions and motions. And then, when she finished her doctorate, she loved being at Chicago. She loved using the Yerkes Observatory for her teaching and for her observing. And she was doing stellar spectroscopy then, afterwards.

10:53And she was incredibly highly cited. She was an incredible researcher in her own right. So, in 1950, she had over 3,000 citations of her work. And three of her papers were in the top 100 papers of 1950. So, she was a really amazing researcher. And what she spent a lot of time doing was spectroscopy. So, this is where you take starlight and then you split it up using a prism or a grating in more modern forms.

11:27And you split it up. Instead of in its white light form, you split it up into its whole rainbow of colours. And if you split it wide enough on wide enough angles, then you get to see absorption lines. So, you can... This is from one of her actual papers. So, this is one of her actual spectra of a star. 17 Leporis, if you're interested. And you get all of these lines in your spectra. So, it doesn't look like a perfect rainbow, but you get all these lines. And these lines are where there's an absence of light, where the light from the star has been absorbed by certain atoms and molecules in the outer atmosphere of the star.

12:05That light disappears. And they're unique for different elements and different molecules. They act like a fingerprint. And so, then from there, you can figure out what elements there are. If there's hydrogen, she's identified here, titanium oxide. There's also oxygen. There's some calcium going on. And then from that, you can infer different properties of stars. So, what her... One of her big discovery was, was actually that not all stars that you can see with your eyes are like the sun.

12:36They're actually very, very different. They have different chemical properties. They have different motions. And they have different ages. And she inferred all of this from the spectra. So, she found out that young stars tend to orbit in the plane of our galaxy. So, and then older ones can have slightly strange, more eccentric orbits. But she was the one who figured out that actually there's a correlation between the ages of stars and the types of motion that they had. But the problem was, while she's working at Yerkes, she figured out that there were no tenured women.

13:15Women were working there, but they were being paid less. They were not being given promotions. They were not being employed at the level that their skill set demanded. And this was common, not just at this university, but right across many universities in America and across the world at the time. And, you know, there's not equal pay, not equal status. There are even things like, at the Palomar Observatory in California, women couldn't go because there weren't any lady toilets. And heavens to Betsy that a lady dare go and use the gents.

13:49No, that was not allowed. And so women were not allowed to even go to certain telescopes. So she was facing many, many barriers. And she felt like she couldn't reach her true potential in academia. So she left and she went off to the Naval Research Laboratory. And she researched things like the structure of the Milky Way. So she was mapping out the Milky Way. She started working on microwave astronomy, using radar to measure the distance to the moon. It was a technique that she helped pioneer.

14:20And she even consulted on Project Vanguard. And the Vanguard 1 satellite is still the older satellite that is still in orbit. So it was launched, I think it was 1958. It was launched. It was a few months after Sputnik. It was the fourth satellite ever launched successfully that made out into space. And this thing is still up there. We expect it to be up there for at least another 200 years. And it is the baseline for all of our weather and climate modeling and atmospheric studies.

14:53So, you know, right from early stages in her career, she was really on the button with what would have lasting future impacts. And so then while she's at the Naval Research Lab, she went to NASA. She attended a lecture. And after the lecture, someone approached her and was like, Nancy, do you know anyone who might be interested in creating a space program? Because over at NASA, we really want to do that. And we're looking for someone. And she sort of went, oh, are you now?

15:26How interesting. And so then she applied for the position. And she ended up getting the position. So in 1959, she became the head of observational astronomy at NASA. And then just a year later, she became NASA's first chief astronomer. And she was, in fact, the first woman to hold an executive position at NASA. She spent her time traveling around and convincing astronomers that space exploration was going to be good for astronomy,

15:58that the rockets were not a bad thing, that they were a good thing, they could be put to advantage. So Kennedy, up here, she's talking to the president. Anyone recognize who this might be?

16:13This is Buzz. She's showing him star charts. So, yeah, she was very important in NASA. And she met with many, many influential people. In 1959, she actually wrote a paper about using coronagraphs to find exoplanets, which is the method that the Nicely Grace Roman Space Telescope will be using to find exoplanets. And we'll explore what we mean by coronagraphs in just a little while. She also believed that a large space telescope in the future would be able to find planets using that astrometry method that she was studying when she was doing her bachelor's.

16:50And this did happen. Glees-876 was a system that was discovered by Hubble to have planets. So, yeah, absolutely. She was on the ball all the way through. She planned satellites and she planned rocket launches. And it was her voice that said yes or no to any proposal sent into NASA until peer review came in in the 1970s. She was the one making the decisions. So, if people wanted a satellite, they wanted to talk about space telescopes, they wanted to launch something,

17:24she was the yes or no right through to the 1970s. And she did, of course, pioneer space telescopes, most famously the Hubble Space Telescope. So, where do space telescopes really come from, especially space telescopes like Hubble? So, in 1962, a study was conducted by the National Academy of Sciences. And they realised, they were like, oh, we've been using, like, you know, the Apollo rockets, exploring space.

17:55We reckon we can fit a three-metre telescope onto one of the Apollo boosters. Seemed a little bit ambitious at the time. Nancy was like, eh, nah. That's too big. The biggest we've sent so far is like this. And you want to go to three metres. Like, too big. And also, the problem that she had with it is because it was rockets and, you know, aerospace at the time was very much a man's world. Not only did they just want to send a three-metre space telescope, they wanted a man to look through it.

18:26So, they wanted to launch a three-metre telescope and literally have a bloke somehow at the eyepiece doing all of his measurements and somehow moving this thing around. Another idea that was thrown out was like, let's put a giant telescope on the moon. But then Nancy was like, dust. The bad dust. You know, obviously not the cosmic dust that we love, but the bad dust of space telescopes, right? You know, astronomers didn't want to send a giant telescope into space with a person, a man,

18:59because he would have been a man at that time. Because, first of all, the whole thing would have to be encased in an atmosphere so that, you know, he didn't die. And then the whole idea of going into space is to get away from the atmosphere. So, it's like, well, what does that do? And then you've got your wiggling issue. You've got an astronaut attached to this telescope. Even if he tries to stay still, he's going to move the thing because he's going to want to breathe. How dare he, right? So, lots of issues of sending a man up with a telescope. So, by the end of the 1960s, start of the 1970s, you know, these ideas of putting something into space have been circulating.

19:37And Nancy has sort of realized, actually, the technology has probably matured enough by this stage that we can make it happen. And so, she brought people together from all over the country, all over America, to design something that would actually work as a space telescope. And she completely oversaw the design of Hubble. So, here she is with, this is an early concept here of the Hubble Space Telescope. And, you know, it's got the little shields here, the different solar panels, for example. It's not too far off what we ended up with.

20:11She completely oversaw the design. She was the one who pushed for CCDs to be included, which was a really new technology at the time. It wasn't tried and tested. So, some people were nervous about including them. But it proved to be a crucial decision, which is why Hubble is still relevant today. So, she retired in 1979, but she continues to consult with NASA, with astronomers, about building telescopes right the way through her life, or almost right through to the end.

20:44She was extraordinarily proud of the Hubble Space Telescope, especially on how it brought astronomy to the masses. That's what she loved, is that you can say to anyone, oh, yeah, the Hubble Telescope, immediately they will know. They may not know much about it, but they've seen the pictures. So, she was incredibly proud of that. And all the way through as well, she continued to advocate for women in science. She would always push women to apply for positions that they didn't think that they could do. She encouraged them to go for promotions. So, she was always a strong, strong advocate for women in science.

21:18And truly, Nancy Grace Roman, she lifted our eyes to the skies, and she revealed the cosmos in extraordinary detail through those space telescopes that she helped plan, design, and commission. And so, I really do think that she has the perfect name for our next generation space telescope.

Origins and Mirror Acquisition

21:41So, where does the idea for Nancy Grace Roman Space Telescope come from? So, our original ideas are coming from around about the 1990s. This is, you know, we're here in 2026 when the thing is launched, but the 1990s is when our ideas first come out. So, from the late 1990s, people are starting to get interested in dark energy. Because using measurements from type 1a supernovae, so type 1a supernovae are when you have a star or a red giant evolved star in orbit with a dead white dwarf star.

22:20That dead white dwarf star steals material from its companion. It eventually gets to an overload point, and it explodes in a supernova. And so, because it's the same system all the time that's exploding, they're standard candles in the sense of we know how bright they should be, so we can compare it to how bright they are, and then we can get interesting distant measurements. And what the distance measurements were for from type 1a supernovae was showing us that actually the expansion of the universe is accelerating, which was not what was predicted by our Big Bang Theory models at all.

22:57So, then people started to get interested in understanding what is this thing that's making the universe expand in ways we don't understand. And so, the idea was that actually maybe the solution to figuring out dark energy would be to have a wide field near infrared space telescope, where you can map the distribution of galaxies, and then you can figure out how the universe is expanding through time. And the idea sort of floating around is that you could have maybe a 1.5-meter telescope, 150-megapixel camera, something like that.

23:34Check it out into deep space. L2 will come onto that in a little bit. Have a look at your galaxies. Have a look at your supernovae like this. Another idea that was being floated around in the 90s was to have some kind of surveyor telescope that operates in the near infrared, so taking grand maps of the night sky, the whole sky, if we can. And that would allow us to find things like planets around other worlds, quasars, these active hearts of galaxies,

24:07where you've got supermassive black holes gobbling up material and shooting out jets. Be able to find those and see how they change through space and time. Even go all the way back almost to the Big Bang. And again, maybe a telescope that's about one and a half meters in diameter, that might work for it. Then another idea that was floating around was to find exoplanets using a process called microlensing.

24:37And looking for exoplanets near the center of our galaxy, so far, far away from us. Now, what do we mean by microlensing? So, what we mean by microlensing is you have a background star, you have a foreground star, and then we're sat down here somewhere observing. And then anything that has mass can bend the path of light due to its gravity, creates curvature in space-time due to its mass. So, then instead of light traveling in a straight line, the light sort of goes and bends around the curvature of space-time.

25:13And so, when they line up perfectly, you get extra light from your background star gets bent around towards you. Instead of just carrying on into space, you get all of this extra light pulled towards you by the gravity of the foreground star. And so, then you get this extra brightness. So, it's like this is acting like a lens. So, that's where this part of the word comes from. And then the micro bit is, because anything that's got mass, that's got gravity, curved space-time,

25:46you've got a planet going around this foreground star. Well, you can get, oh, if I go here, a micro boost from the planet. So, it's exactly the same concept, but because its mass is so much less, you get only a small bit of extra light pulled, bent round. And so, then this extra little blip betrays the presence of a planet around this star here, the foreground star. So, you've got your micro lens in. That's where the name comes from.

26:18And so, this was thought to be a great technique to find lots and lots of other worlds. And so, all of these ideas are knocking around from the late 90s through into the 2000s. And again, you just want a 1.1 meter telescope to do this kind of science. And then in 2010, we get the decadal survey. The decadal survey is essentially all of the astronomers all around the world club together once a decade, and they say, what is the most important science for the next decade?

26:51What do we want to focus on? What are going to be our goals? What should be prioritized? And out of this decadal survey came one telescope. This was going to be the priority. This is what everyone should be working on. That could help us understand dark energy. It could map the cosmos in the infrared and help us find exoplanets. And this is where W first was born. The Wide Field Infrared Survey Telescope, which would have a size of about 1.4 meters.

27:25But there was a very split camp. Would 1.4-ish meters be big enough in order to achieve these very, very lofty goals? So all astronomers are debating about this, wondering, worrying. At the same time, the National Reconnaissance Office is working with Boeing on spy satellites, right? And so they started this project in 2005, sorry, in 1999.

27:56But it was canned in 2005 due to budget overstretching, which I think is a theme with Boeing, if we're being honest. And so during the development of these kind of massive spy satellites that they were working on, they created two very large 2.4-meter diameter mirrors, which were just kicking about. And so the National Reconnaissance Office phoned NASA and was like, we've got some mirrors, do you want them?

28:26And NASA went, duh, obviously. And so the National Reconnaissance Office gave NASA these giant mirrors, along with all of the electronics to go with them. And one of these mirrors went into Roman. Now, of course, it had to be redesigned. Redesigned the electronics had to be worked on in order to repurpose it for NASA's purposes. But it was absolutely worth it because it gave so much more aperture to this telescope. And it's enabled it to do, well, it will do amazing things.

28:59And we don't know what's happening with the other one. So the other 2.4-meter mirror is still kicking around at NASA. So if you've got a good idea to use a 2.4-meter right into NASA... Another... Yeah. Bob, Bob. Yeah, Bob the dog too. Oh, it's a Bob 2.4.

Journey to Lagrange Point 2

29:18So the Nancy Grace Roman Space Telescope, it came to fruition. It launched at the end of August this year on a Falcon Heavy. Unbelievably, get this, when does this happen? Nine months ahead of schedule. Nine months ahead, right? And in budget at $4.3 billion. And that's for design, construction, and continued operations as well.

29:49So this telescope is well on its way to its final destination, which is L2. So we're just going to come on to that next. It's going to take about 100 days until it's into its final orbit. It takes about a month to get to L2, and then it's got to enter its orbit at this point, which I'll talk about next. So where are we in terms of how this telescope is being deployed? So all of its antennae have been deployed.

30:19Its solar panels, as you can see here in this artist's impression, they're all folded out as well. The sunshade has been deployed as well. Some of the instruments have been turned on. So, you know, it's talking to Earth. Everything is looking quite tickety-boo with it at the minute. So I'll just spin it around so that we can see. There we go. This is the sunshade deploying just at the front of the telescope, all the solar panels.

30:49That dish there is how it communicates with Earth, so how it sends back its data. And there we go. If you're interested, you can actually see exactly where the 90 Great Roman Space Telescope is on its journey with eyes.nasa.gov. And it's a 3D rendition of, like, planets in the solar system, other space telescopes and things like that. And if you hop on there, it shows you in real time where this telescope actually is. I checked about a week ago.

31:20So this is that eyes.nasa.gov website. So here's where it was. So Earth is at the centre here from this particular viewpoint. So you can see where some other telescopes are, like TESS, the exoplanet Hunter, Chandra as well. These are sort of Earth orbiting. But you can see that this telescope is heading far away from Earth. So far away. This is the moon's orbit here. And this telescope is barreling straight away from our planet. And it is heading off to L2.

31:51It's going to be joining some other deep space telescopes like Euclid, like the James Webb Space Telescope. So what do we mean by L2? So because the Nancy Grace Roman Telescope sees mostly infrared light. So what is infrared? We're talking about heat energy, essentially. It's if you think of the rainbow, it's the light past the red end of the rainbow. So it's the sort of light that they're using in, like, airports to do scanning.

32:23If you ever had to go on a thermal camera, maybe you've had your roof checked with a thermal camera. That sort of light. And so because it's essentially detecting the heat energy of the universe, we don't want it near any big heat sources. Don't want it near Earth. We don't want it near the moon. And so we send it out to this place here called L2, Lagrange Point 2, which is about a million miles away from Earth. It's about four times the distance between the Earth and the moon.

32:53So L2 is where we send a lot of our space telescopes. And L2 is a gravitationally stable point. These emerge naturally between any two large body systems. So there's Lagrange points around Jupiter. There's Lagrange points around Mars. We've got Lagrange points as well. So L1 is where we stick a lot of our solar telescopes because it's a gravitationally stable point. You don't need a lot of fuel to stay there. And you take the same amount of time to orbit the sun as Earth does.

33:26And that is because you've got a kind of little bit. Earth's gravity is pulling you this way. The sun's gravity is pulling you that way. And so it balances out quite nicely. L3, that would be where Nibiru would be if it was real. So you know when they're all about, oh, there's a planet. It orbits the sun exactly opposite to where Earth is.

33:47That's where that planet would be, would be at L3. Then L4 and L5, they make an equilateral triangle with your two bodies. So in this case, the sun and the Earth. And then you've got the points here. And these are equilateral triangles. If you've ever heard of the Jupiter-Trojan asteroids, that's where they sit. L4 and L5, but around Jupiter. And then L2, L2 out here is thermally stable. You take the same amount of time to orbit the sun as Earth because you get an extra gravitational kick from Earth.

34:19And so then that allows you to co-orbit. And so this is why we stick things out at L2. Because you can stay in continuous contact with your telescope. You're away from thermal heat sinks. It doesn't take much fuel to stay there. So your missions can last a really long time. But I feel like saying, oh, it's going a million miles away is like a really abstract concept. It's like, what even is a million miles, right? And so this is my favorite sort of diagram, I think, to illustrate this.

34:52So this is the only diagram that I have ever found, comes from ESA, I think it's ESA, where you've got the Moon and the Earth to scale. And then the distance between them is to scale. So here's the Earth over here. And that tiny little blob there, that's your Moon. So the relative size of the Earth, the Moon is right. And the distance between them then for this size is also right. So it's going four times further away.

35:25So it's going from Earth out, out, out. Oh, animation the wrong way. But all the way out here. So this gives you an idea of just how far away these telescopes are. They're so far away that we can't go and fix them, unlike Hubble. We can't go and refuel them yet. But the 90-grace Roman Space Telescope was designed to be refueled. So when we develop that technology in the future, we can go and make it work for even longer.

35:58And telescopes at L2, so this is JWST animation, but it works as well for Roman. They don't sit at the gravitational point itself, because otherwise the Earth would eclipse the Sun all the time. And often these things are solar-powered, so that's no good. So what they do is they orbit the point like this. Huge orbits that take about six months to complete. And so this is why you need a little bit of fuel, but not loads and loads. And what it means is that at any given time, you've got just over half the sky visible to you.

36:31And over the course of a year, you can map the entire night sky, if that's what you want to do.

Optics and Wide Field Instrument

36:38So this telescope compared to Hubble. It has the same size mirror as Hubble, 2.4 metres in diameter. And the carcass itself, the body of the telescope, is also about the same sort of size. We don't have the giant solar panels sticking out to the side like we do with Hubble, which we can see on the right, because they're situated on the top like that. So it's always got its back to the Sun to keep away that heat. It's got all these radiators to dissipate all the heat out as well, because Hubble is in low Earth orbit.

37:14So, you know, you can put its solar panels whichever way you want. But you always want Roman to have its back to the Sun. So that's why it's got its solar panels on the back like that. With a combination of its sun shield and its radiators and that visor, it gets cooled down to about minus eight degrees. That's its sort of general operating temperature. But then instruments themselves are cooled down even further. And you cool down infrared telescopes so that they're not seeing their own heat. They're just seeing the heat of space.

37:46That 2.4 metre mirror, though, has come a long way. So even though it's the same size as Hubble, modern engineering means it only was less than a quarter of the weight of Hubble's telescope, Hubble's mirror. And that means you can fit lots more interesting instrumentation on. It's an incredibly smooth mirror. The impurities, so the errors in the curvature and the kind of, you know, faults on it. There's nothing bigger than 1.2 nanometres.

38:17Now, what's 1.2 nanometres? Half the width of a strand of DNA or about five atoms. Depends on the size of your atom. That's how big your impurities are. That is it. It is super, super smooth. And you need that in order to find these exoplanets using its novel way. So it's got only two instruments on board. The wide field instrument and then the coronagraph instrument. So the wide field is cooled down to about minus 180 degrees, so liquid oxygen, and then the coronagraph down to minus 90.

38:57So they do operate at very, very cool temperatures. And the optical system on the Nancy Grace Roman Space Telescope really is incredible. So here is the Nancy Grace Roman Space Telescope. And its very clever optical system gives it a field of view 100 times Hubble's. So that little square is what Hubble sees. And then that's what Roman sees, is that great big curved tiled image.

39:28So the way the light path works for Roman is it's a novel three-mirror system. So Hubble works with two mirrors, but this one works with three. So you have your primary mirror that collects your light, directs it to the secondary up here, which is about 60 centimetres across, and then sends it off to a system with a tertiary mirror. It then goes through various filters, depending on what you want to look at. And so you can, there's a bunch of different filters, which I'll show you afterwards.

40:00You take your pictures at different wavelengths of light, essentially. But what this tertiary mirror system gives you is, instead of all of the focus being in the middle, so everything's nice and focused here, the best focus is actually in a donut in the focal plane. So instead of the middle being nice and sharp, it's this donut. And this is why the sensor chip for the Nancy Grace Roman is this curved shape, because it's sampling part of that curve.

40:30And that redesign of the optical system to give you focus in a curve is what gives it this super wide field of view. So just to have a look at this again, your light comes in, hits your primary, goes up to your second, and this can tilt about to make sure that you get nice focus. And then it goes down to some flat mirrors just to redirect the light. And then your tertiary also moves around. And together, they work to give you this wide field of view.

41:03So it's not that, like, the secondary is doing corrections and the tertiary is doing corrections. It's they work together to give you this wide field of view.

41:14It's something that's called three mirror and a stigmat. That's what they call it. This is, like, the whole optical system. And what this system does, which was designed decades ago, but it's only been put into operation here, is it corrects so many issues like spherical aberration, coma, astigmatism, field curvature. Any images out here will know what I'm referring to. So it's things like coma is where when you've got stars off at the edge of your field, your light doesn't come into a sharp point like this.

41:47It comes out all smeary and everything kind of looks like a comet. So it corrects for coma. You've got things like astigmatism. I've got astigmatism in my eyes. If anyone's got squished eyeballs like me, yeah, you know, then you look at bright lights and everything's like, right? So astigmatism is corrected for here. This is where instead of your lights coming to a nice sharp point, it spreads out in lines. And this system corrects for that. Your field curvature. This is where if your field is not flat, you have things in focus in the middle,

42:24but not at the outer edges. And so it corrects for this field curvature. And then you've got things like spherical aberration as well, where when your light hits different parts of the mirror, it doesn't come into focus properly. But this system is correcting for all of this. And this is why, because it does such a detailed work in correcting, that you end up with not a focus in the middle, but your best focus like a donut. And then the camera system samples some of that donut,

42:57which is why it's this curved shape. It's not just sort of one square. It's this curve to sample as much of that ring as it can. Now, that's the wide field instrument. And you may note that there are gaps in between all of these sensors. That is true. But you correct for those by dithering. So what that means is you take your picture, you offset slightly, take another picture, it fills in the gaps, you offset again, and then over time, you fill in all of the gaps.

43:30So they are, the size, according to America, the size of a saltine cracker, which only means something to dust in, right? It's about the size of a ritz. A ritz is like a round saltine in terms of size. Yeah, so all of these are about the size of a ritz cracker. They're made of mercury, cadmium, telluride, good for infrared light. That's the choice behind that particular material. Together, there's over 300 million active pixels

44:03in this detector array. 300 million. And it gives you a field of view that's 0.8 by 0.4 degrees, right? It's astonishing. How does that compare to Hubble? If you squint, I promise you that this is the pillars of creation. As imaged by Hubble, okay? This is the classic Hubble view of the pillars of creation. But Roman will give us that.

44:33It's astonishing, isn't it? Okay, after a bit of dithering to fill in the gaps. But this is what it will give us. This is the field of view of Roman, but at the same resolution, because of this clever three-mirror system. If it's looking at, for example, Andromeda, which many of us will look at at camp, that's what Hubble sees. And that's what Roman will see. And then that's the full moon to scale. It's absolutely astonishing,

45:03but with the same level of detail as Hubble. So here's some examples of Hubble fields of view compared to... It says W1st here. That's the old name for Roman. But you've got details like individual stars in the Andromeda galaxy, dust clouds, all the really, really fine details, but a hundred times. You can see, you know, stars in distant galaxies.

45:34You can see deep down into the cores of globular clusters, very faint dwarf galaxies. And then, of course, really, really distant galaxies, which appear like tiny little blobs, but Roman can capture them all in such great detail, again, compared to the field of view of Hubble. So how's it going to do all of its kind of work?

Primary Surveys and Filters

45:56Well, three main surveys, really. One is the high latitude wide area survey, a very straightforward name for astronomers. A map about 12% of the night sky and a year and a half or so will be dedicated to this over the five years. And these maps will have over the wide area, this is where we're counting those billion of galaxies that we spoke about right at the beginning. There is then the Galactic Bulge Time Domain Survey.

46:29So this is where it's focusing on regions near the centre of our galaxy and looking for those 100,000 exoplanets, but also transients. So this could be supernovae, for example. It could be maybe some asteroids in our own solar system will get into the way. Transients is anything that changes. So something can flare and change in brightness or something can move in space. And so that's a change there as well. And also it can hunt maybe

47:00for some small stellar mass black holes. Then as well, we have the high latitude time domain survey. So this is kind of like your Hubble Deep Field. This is what Roman's equivalent is going to be, where it'll stare at a patch of sky, keep rotating around, doing that dithering to fill in all of the gaps. And again, start mapping out those billion galaxies, looking for supernovae, start doing those studies for dark matter and dark energy.

47:33Just for those who are interested, this is a bit more of a technical slide, but just for those who were interested in this kind of thing, there's a bunch of different filters on the Nancy Grace Roman that span just from just the visible and then down into the infrared. And then the spectra that we talked about, where you spread that light out into a rainbow, you've got a prism and a grism as an option for that. Your grism, which is a grating prism system,

48:04so we're talking about lots and lots of narrow lines, spread out your light. That you're kind of using for your galaxy studies because it's easy to switch between taking pictures and taking the spectra. And then your prism is a bit rougher, but it's better for fainter objects like your supernovae because it doesn't spread the light out too much because the more you spread out the light, the fainter that light then appears. So in terms of the grism, what do we mean? Looks something a little bit like this.

48:36So as an example, this is a simulation. This would be your picture of your galaxies, your picture of your night sky. You then switch over to the prism. You're spreading out the light into different wavelengths. And so that's how it then appears. And this data is read out. So you can see here, we've got one, two, three, four bright. And then we've got our one, two, three, four bright streaks of light. So that's, and you can flip between the two then. So you can map your spectra onto what objects you're looking at.

Coronagraph Technology Demonstration

49:07Now, the coronagraph. The coronagraph, this is really novel technology demonstration. This is. It takes a different portion of that donut of light that's in focus. So it doesn't use the same light as the other instrument. So you can operate them together on occasion, sort of doubling your science output. And what is special about this, this technology demonstration, is it blocks out starlight, which is what a coronagraph is,

49:37to reveal the faint light from planets, but does it in an absolutely novel way. So these are some examples where we've blocked out starlight in order to see the light from planets. Because the light from planets can be 10,000 times fainter, 100 times thousands fainter, right down to a billion times fainter than your star. And so unless you block out your starlight, you'll never find that light that's coming from the planets. And they can either be reflected light

50:08or light actually emitted by the planets themselves. So this is a GIF, and I love a GIF. So here's all these dots here. These are the planets actually orbiting that star. It's a system that we've revisited over and over. And so you can actually watch the orbital motion of these planets around this star. And then here, here you can see another orbit, except that this one, instead of orbiting in the plane, like they are here, this one's orbiting like this. So you can see that this planet

50:38starts far out from its central star, and then it starts to get closer and closer and closer, and then we lose sight of it at this point, but then two years later, it pops out on the other side of the star. So this is what chronographs do, is they physically block out the starlight, so that then you can detect the fainter light from orbiting planets. And a basic version kind of goes like this, where you have your star,

51:09you physically put a blocker in the way for the starlight, you then have something called a light stop, which is like a disk that blocks, and that blocks out any starlight that's been scattered around through your optics, and then that's your result at the end. But the Nancy Grace Roman is taking it one step further, because it's testing out being able to have not only your mask and then your disk that blocks as well, but two deformable mirrors,

51:42each with over 2,000 actuators, so 2,000 little pistons, so it can move, and in real time, through a feedback loop, see how you've got all speckles of starlight that are bouncing off the edge of the optics, bouncing off, you know, edges of mirrors, things like that, and get rid of them in real time to reveal then your fainter planets. If this works, because we don't know, we're testing it, but if it works,

52:12we'll be able to see planets hundreds, thousands of times fainter than what we're able to detect now. And then the next generation will allow us to see Earth-like planets in the habitable zone of their host stars. So this is the test, but then the next gen is when we find, actually find, Earth 2.0. Not that you know, two dozen Earth 2.0s that have been found in the media so far. So there's a little

52:42animation here. So here we've got, is it playing? Yeah. Okay, so.

52:51Oh, hang on. Go back a bit more. Okay, so. Go there. Okay. There's our bright star. And then we would, in like a basic form of a chronograph, you block out your light with your main mask. So here we go. Here's our main mask, which is blocking out our star light. So we pop that in to where our light is going through our mirrors.

53:22And then we put in our light stop, which gets rid of most of the scattered light. But it doesn't do the full job. So it does a decent job. So this is our, what we're left with after we've blocked out our star light. We can't quite see the planets yet. And so the light gets all of these, this scattered light, all of the distortions from bouncing off all of the edges of the optical system. So you get a bit of a mess like this in your picture, which isn't any good at all. But the Nancy Grace Roman

53:53is testing out this mirror system where you have all of these individual pistons and light is fed to a camera system, to the camera system. It's fed back through the computers. And in real time, it'll make an adjustment, see if the picture's better. And if it isn't, it'll make another adjustment and another one and another one. But of course, you know, a computer's making these decisions. So they're happening in microseconds. And then when you get the adjustments correct, those hidden planets that were lost in all of the scattered light,

54:24they then start popping into view and you can detect them. So this is the test for this technology. It's new. We don't know if it's going to, you know, be as good as we want it to be, but that is the hope.

Dark Matter and Dark Energy Goals

54:39And so then,

Dark Matter and Dark Energy Goals

54:40last couple of slides, just to remind you what the three kind of goals are for the Nancy Grace Roman. So its first goal is to help us understand dark matter. Now, dark matter, we know, exists. It's this invisible glue that holds together galaxies that are spinning so rapidly they should be flinging themselves apart, but they're not. And we know they're not because we live in a galaxy and our galaxy is still here. It also holds galaxies together

55:10in clusters because they're moving so quickly they should be flinging themselves out into space, but they aren't. And so we know dark matter exists through its gravitational effects, but we can't see it. It doesn't interact with light. It makes it very difficult to study. But by measuring the distribution of these galaxies and measuring how light is impacted by the gravity of dark matter, how that dark matter pulls that light in, acts as a lens, just like the microlens that we talked about, we can hopefully start

55:41to infer the distribution of dark matter and then figure out what it is. Dark energy then, we mentioned this increasing, this more rapid expansion of the universe that disagrees with what we were expecting. Again, the distribution of galaxies will hopefully help us understand it. because the problem is dark matter makes up like 27% of the matter energy content of the universe. The stuff that we see

56:12and interact with is about four and then the rest of it is dark energy. So it's like, we know nothing about the universe we live in and hopefully this telescope will help us figure that out. and then of course the final goal is to try and find 100,000 exoplanets using microlensing and then of course, so here we go, this little video I'll explain in just a second and again test out

56:42that coronagraph instrument to try and actually take pictures of ever fainter planets that are orbiting their star. So this is that microlensing so here's your images of the stars they get brighter and then you get an extra little brightness in your multiple images of stars which is that microlensing event from the planet so I'll just play that again there it goes.

57:12So watch the brightness of these images these apparent images of stars you can see that they get nice and bright when we've got that lensing event and then there's our extra brightness from the microlensing of the planet and so some people may ask or may ask you I know you guys won't ask this question but some guys may ask you do we really need another space telescope right because we've got

57:43all of these ones so do we need another so for me JWST is our microscope in the skies sees down into the devil details Hubble sees different types of light it sees from the ultraviolet down to the infrared Euclid sees more of the sky but then Roman sees that sky in incredible detail and is poised to help us find so many more planets and test out actually seeing them in five years

58:15of operations this is my final thought to leave you with the Roman space telescope will gather as much data as 50 Hubble's operating for three decades in five years so in five years 50 Hubble's for 30 years it's absolutely astonishing but they do complement each other they do different jobs and they will change our understanding of the cosmos in ways that we cannot imagine and that

58:45is the Nancy Grace Roman space telescope thank you very much yeah good

Audience Q and A

58:55questions right questions can you start that again for us please you can listen to the audio recording on awesome astronomy so questions hi great talk Jen I'm interested in the chronograph you mentioned the deformable mirrors to cancel out the effect of light scattering from the parent star now those deformable mirrors

59:25I mean that's just normal adaptive optics which has been used in a lot of technology so I don't the actual technology works so I don't know maybe in the context of which the environment is in it's different but I can't see how there would be a problem in technology so what they want to test is yeah so adaptive optics works you know it's well tested in terms of like using lasers and things like that it's because they're using like the

59:55image and the focal plane to do the feedback so that's new to fly that in space has not been done before to use it in the kind of the environment of a coronagraph it's like will it the question is we know that it'll work in the sense of it will reduce the scattered light will it reduce the scattered light enough to like yeah yeah so yeah yeah so I mean you know they're not gonna fly it unless they think it's got a good

1:00:26chance of working but because it's not proven technology you know it's like this is if it works then the next generation yeah will be great it will be even better so it's like you know they're only gonna look at a couple of dozen systems with Roman because the idea is to test it to see okay well can it see this can it see that no that's too faint right so this one is not so much gonna like the coronagraph is not the discovery instrument it's the we know about these systems let's

1:00:56see if we can actually see them and then the discovery then is is the image plane the wide field instrument yeah but yeah great question any others with the lenses that you mentioned about the different colored lenses I forget what it was called but the different colored lenses the filters filters thank you very much I'm newbie I'm forgetting the question yeah yes on that one is it continually moving so that it's sending back

1:01:26images all the time with those continually moving or or is or is it actually being asked to change to a particular filter yeah great question so they'll kind of systematically go through the different filters depending on you know what their target is and what the the images are so you know they'll have an observing plan for all of these wide field images and it'll be right we'll do this color for this section and then we'll do that

1:01:57color and then we'll do the next color and kind of systematically move through because it might you know need to react to interesting things as well that are happening and you might want specific wavelengths for that so it's sort of like the telescope will choose where what it's using to image in in time and like where where it's appropriate you you mentioned towards the end on your last slide the amount of data that this thing is going to generate yes has there been any

1:02:28more developments in terms of the mechanism to get that back to earth or is it just tried and tested it's the standard sending it back with it's got big dish to send back because it's 1.4 terabytes a day one point every day like 1.4 terabytes yeah so um yeah i think it's just the standard dish yeah i don't think they're doing laser communication because of the distance um but yeah so it'll it'll have sort of downtime i think

1:02:59hubble was like 50 gig and a night or something like yeah yeah one i did want to make because you're um we were talking about the andromeda galaxy and hubble imaged that it took like 430 something images over three years to build the andromeda galaxy and roman's gonna do the same picture in two 90 minute sessions yeah it's yeah it's insane so the great comparison is like is this curved square

1:03:30grid yeah 430 hubble squares all over it so that little square times for however many yeah yes all of the instruments you mentioned are they running simultaneously so um most of the time they run individually but um when you are setting up the coronagraph you can then use the wide field at the same time um so it's they can't always operate at the same time because you need to sort of move the telescope in a

1:04:01specific way to engage the coronagraph and so then that interferes with what the wide field wants to do and then like the operating status for wide field doesn't really work with the coronagraph but in certain setup modes when they're kind of getting ready you can have the light being directed to both instruments because it's sampling a different part of the focal plane so you can like squeeze a little bit more science out on the um coronagraph uh front um appreciate this is untested technology with the adaptive optics etc do

1:04:33we see um the possibility of applications happening on terrestrial observing so yeah if we can you know um they already shine lasers don't they to talk about atmospheric extortion yeah so having um yeah the actuating mirrors that's also used on the ground it's just never been put into space with this many actuators in a coronagraph setting and to sort of have it feedback looping in this particular way so although sort of having deformable mirrors itself is not a new

1:05:05concept it's like the way it's packaged together is the way it hasn't been tested so yeah you know coronagraphs on earth are we are we we like oh yeah no so um yeah they do use the um coronagraphs on earth as well but it's just you can't get down to the faintness levels um because the atmosphere you know this one is only dealing with distortions from the edges of the optics and things like that whereas then when you're on the ground you're dealing with the atmosphere going

1:05:35at you as well so how'd it go yeah i advise it extremely technical i got that from nasa right so but yeah great question why does um the roman use sort of that particular sort of um array shape for the sensor why not something simpler like just big square or something

1:06:05like that why is it that interesting shape so it's curved to sample that um that focus donut that you have um but then in terms of not having bigger sensors it's like the bigger you build the sensor the more likely it is that something's going to go wrong you're going to have to start again whereas if you have lots of small ones um it's sort of engineering wise it's it's easier to start over if it's just a little bit um and then put all together i'm sure they would have loved to have one giant sensor um and then also

1:06:35when you're reading out the information having the individual sensors you can kind of read them out together um so it's sort of a combination of engineering and reads out and electronics um things like that so yeah in an ideal world it would be one giant thing but um unfortunately we're sort of somewhat limited uh by by the engineering so it's built built in sections to to make it last um but i don't know why it's 18 segments why it's this exact shape it's just that's what they decided would would work be

1:07:07optimized um there's also the balance of weight as well and when you're launching so you know you've got a finite amount of weight that you've got to work with you want to cram as much on and so that will be a consideration that goes into the design as well it's a great question though next oh you're making me run correct the um defects such as coma you mentioned why and this is on behalf of takahashi images by the way why why don't they

1:07:37just use bxt yeah uh you'll have to write into nasa on that one maybe it's a trick that they're missing out on next are you all are we done are we done oh no oh the threat of being done where was that hand oh there oh there oh look you mentioned how many pixels were there's like 300 million yeah

1:08:07can you pull spectroscopy off each pixel that's a great question oh yes i think i think i think it is yeah i is is spectra off each pixel i think it is which is insane yeah that you can get 300 million spectra in one punch yeah i'm just wondering with such wide field individual targets regions of interest will they be

1:08:38indexed available so if somebody wants to look at a particular star that has been imaged will that be something that people can look up and do so all of the data from roman is immediately publicly available yeah so so yeah they it gets you know analyzed and sort of reduced to a manageable size from 1.4 terabytes a day so it gets broken down um but then it's immediately out to the public much like you know like the from the mars rovers as soon as

1:09:09they've been that data down within like 48 hours it's out on the websites it's a legal obligation isn't it isn't it it's actually like congressional kind of yeah it has to go out within like so many days so yes it you will be able to then go and see the roman pictures oh get your steps in get my steps i did 8k this morning i know well now you've done 9k hi yeah um so with the 1.4 terabytes a day um i had a uh a

1:09:41friend of mine um when the lhg was being created was working on a project with cardiff uni and i think the max plank institute in terms of handling the amount of data that the lhc would generate yeah at the time and the fear being like there's no computer systems or storage systems etc fast enough etc to deal with the data are there any similar research projects or stories that you're aware of that are going on in the background in terms of like behind the scenes of what's being put in place to support yeah the mass roman data it's uh ai there's a lot of uh it's the same

1:10:13with like the vera rubin telescope because that that is producing so much data as well so um astronomers never see the raw data now it's just that it's too much to be handled and often they don't even download the data it's sort of they access servers um to then do the work remotely because it's just too much to download so um the data gets pulled down it gets run through pipelines um to kind of get it into a manageable state for astronomers to then access and use and then yeah a lot of that is being

1:10:43developed and it and it uses ai so it's a good use for ai question it's not it's not completely dirty but it's oh i i don't know the amount of water that they're using and yeah yeah yeah um any more but also um um kevin pointed out um something i failed to mention uh if you haven't done so already you can adopt a pixel on the nancy grace roman telescope um and you can then be like you see that

1:11:14star that's my star it's taken with my pixel so yeah you just head head to the nasa website you just put your email in um and then in the end you get assigned a pixel so yeah it's it's quite fun and it's free yeah as you know your data just the cost of that are we done they've had enough all right thank you so much for coming

Credits and Closing

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