Episode 17: Space Telescopes!

with Dr Steve Crawford and Professor Jayanne English

In Episode 17 of The Cosmic Savannah, we discuss space telescopes! We talk about the amazing Hubble Space Telescope and the upcoming James Webb Space Telescope (JWST).

Jacinta gleefully visiting the James Webb Space Telescope.

We sit down with Dr Steve Crawford from the Space Telescope Science Institute (STScI) in Maryland, USA, and formerly SALT. Steve explains how his team deliver data from space telescopes to scientists on Earth.

Professor Jayanne English from the University of Manitoba, Canada, then gives us insight on how she and others create the beautiful images we see from the Hubble Telescope. And how the myriad of data collected is incorporated into one beautiful image.

Prof Jayanne English signing Jacinta’s book!

This week’s guests:

Featured Image:
The CTB 1 supernova remnant resembles a ghostly bubble in this image, which combines new 1.5 gigahertz observations from the Very Large Array (VLA) radio telescope (orange, near center) with older observations from the Dominion Radio Astrophysical Observatory’s Canadian Galactic Plane Survey (1.42 gigahertz, magenta and yellow; 408 megahertz, green) and infrared data (blue). The VLA data clearly reveal the straight, glowing trail from pulsar J0002+6216 and the curved rim of the remnant’s shell. CTB 1 is about half a degree across, the apparent size of a full Moon.

Credits: Composite by Jayanne English, University of Manitoba, using data from NRAO/F. Schinzel et al., DRAO/Canadian Galactic Plane Survey and NASA/IRAS

Related Links:
SALT: http://www.salt.ac.za
The Space Telescope Science Institute: http://www.stsci.edu/
University of Manitoba: http://umanitoba.ca/
The Hubble Heritage Project Website: heritage.stsci.edu

Transcript

(By Alicen Munn)

Jacinta: [00:00:00] Welcome to The Cosmic Savannah with Dr Jacinta Delhaize.

Dan: [00:00:08] And Dr Daniel Cunnama. Each episode, we’ll be giving you a look behind the scenes look at the world-class astronomy and astrophysics happening under African skies.

Jacinta: [00:00:17] Let us introduce you to the people involved, the technology we use, the exciting work we do, and the fascinating discoveries we make.

Dan: [00:00:24] Sit back and relax as we take you on a Safari through the skies.

Jacinta: [00:00:35] Hello, welcome to episode 17.

Dan: [00:00:35] Hello.

Jacinta:  [00:00:36] Today we are going to be talking all about some optical infrared telescopes. So we’ve talked a lot about radio astronomy because I’m a radio astronomer, but we’re gonna, we’re gonna squish those wavelengths down a bit today… talk about optical just like the SALT telescope in Sutherland in South Africa. But this time we’re going to be talking about optical near-infrared telescopes that are up in space.

Dan: [00:01:02] Yeah. So first we are joined by Dr Steve Crawford. He’s from the Space Telescope Science Institute in Maryland in the USA, and that is the home of Hubble. The Hubble Space Telescope, and will be the home of JWST, which is the James Webb Space Telescope, which is going to be launching soon.

Jacinta: [00:01:23] Soon… It’s delayed by a few years, so we’re not exactly sure when, but it’s going to be the successor to Hubble. And at STScI, there’s the control centre for JWST and Dan, did you know I’ve actually been there?

Dan: [00:01:39] I did know that.

Jacinta: [00:01:42] Um, pretend you don’t? Yeah, so it was in 2016 I went to the US for a conference. I went to the Space Telescope Science Institute STScI, home of Hubble. And, I got to see the control centre for JWST and I even got to see JWST itself.

Dan: [00:02:04] Yeah. So for the listeners, JWST is this huge telescope which is going to go up into space. I think the current plan is 2021 for the launch, and it has 18 hexagonal mirrors, which will fold out when in space and a total diameter of just over six meters when it’s folded out. So Hubble was 2.4 meters, so it’s more than double the size of Hubble.

Jacinta: [00:02:30] Yeah, it’s a beast. So I saw it at NASA Goddard. It was in the construction chamber, and that day they had unfurled the solar panels and it was facing towards us in the viewing gallery so we could see all of the hexagonal mirrors and they were amazing. They’re gold, they’re golden in colour. I don’t know if they’re plated in gold or something golden coloured, but it was really, really incredible. It’s a spectacular telescope, so we’re all going to be nervously holding our breath when it launches.

Dan: [00:02:59] I think it’s actual gold because it’s a really good reflector in optical and infrared.

Jacinta: [00:03:04] That would make sense.

Dan: [00:03:05] So we spoke to Dr Steve Crawford who is responsible for the data delivery for JWST. He was previously here in South Africa and he was responsible for the data products for SALT, the SALT telescope.

Now he has moved to the Space Telescope Science Institute to work on how we get from JWST – this telescope, which will be in space. The images it takes, the data it takes and how we get that to the scientists so the scientists can do as little as possible or they can get their products ready for science. So that’s a large project which happens within the Space Telescope Science Institute.

Jacinta: [00:03:47] Yeah, and then we’re going to speak to Professor Jayanne English from the University of Manitoba in Canada. And she’s going to tell us about once we’ve got the data, once we’ve done the science, how we then get that to you, to the public and how we can visualize the data and the images so that you get to see it. 

Because there’s no eyepiece to Hubble or JWST. You can’t look through it, and even if you did, you wouldn’t see these beautiful pictures that we see in beautiful books and online. There’s a lot of thought that goes into designing those images. We’ll hear about that from Jayanne.

Dan: [00:04:29] Great, so let’s hear what Steve had to say.

Today, we’re joined by Dr Steve Crawford, who is joining us all the way from the USA, Maryland and the Space Telescope Institute. Welcome to the Cosmic Savannah, Steve.

Steve: [00:04:49] Thanks Daniel, it’s nice to be here.

Dan: [00:04:52] Um, you’re not just joining us all the way from the USA. You have a history with SAAO and South Africa having worked here for many years. Do you want to tell us a little bit about your time here and what you did?

Steve: [00:05:04] Sure. I actually moved here in 2006 to actually start with the SALT commissioning. To help with that and to start using SALT when it was having its first flight.

A little after a year of being here I took up a position as a SALT science data manager. In that position, I helped to oversee the data as it came off the telescope and was then distributed to the partners. And I helped develop the software which was maintaining all of that architecture, but also for calibrating the data. So making the data ready for being used by the scientist.

During that time I also did my own research into a wide range of different things of basically all the different things that we could look at SALT with and was very much involved with the commissioning and getting the telescope off the ground and being used by the community.

Dan: [00:06:03] Yeah, we’ve spoken once before. We spoke with Moses Mogotsi in the first episode about SALT and how it is managed, that it’s a queue schedule telescope. Partners put in proposals for observations and then the SALT astronomers go off and observe them and then deliver their data to the partners.

So when you talk about this data management role that you were involved in, is there some sort of system that’s in place, an automated system, or is there something which is fairly manual still?

Steve: [00:06:40] Very early on we set up an automatic system that would actually, once data came down from the telescope so the observations would happen up in Sutherland and the data would be transferred down to Cape Town. That was set up as an automatic transfer. And then each morning following the observations, there’d be actually the SALT pipeline, which would run the data through an automatic process where it would clean up the data a little bit and organize it. It would then remove detector effects and instrumental effects which were seen in the data and then it would actually make the data available to the principal investigators; the astronomers who were doing the observations around the world.

And so, basically right after you’re having your first cup of coffee in the morning, you’d also be getting your SALT data from the night before, so you could start looking at the science right away.

Dan: [00:07:34] So it’s nicely, neatly packaged, cleaned and produced for you. In terms of detector and instrument defects, you mentioned what do those look like and how do we detect them? How do they come about firstly, and then how are you detecting them and removing them?

Steve: [00:07:49] Yeah, the instruments on SALT, mainly the detectors were charged coupled devices. And with these, they basically turn photons of light into electrons. In that process, there’s different effects that have to be corrected for, like the bias level of the detector, the response of the detector – not all of the pixels have the same response – and also how those detectors are oriented. You’d also have instrumental effects, especially when using the spectrographs on SALT to the main instruments or the main instruments on SALT are our SALTICAM and imager.

And then the Robert Stobie spectrograph and the high-resolution spectrograph, which break light up into the individual components. And one of the things you’d want to do is actually match that light that you’re observing with the wavelength of that light. And so we provide tools to actually allow the wavelengths to be actually measured and so you could actually know exactly at what wavelength and how bright your source was shining.

Dan: [00:08:57] I mean, it’s pretty complicated. So you’re doing all of this stuff so that the observer doesn’t have to get into these details I assume?

Steve: [00:09:05] That’s correct. This has to be done almost to every data set no matter what type of science someone is interested in doing.

And so by having a common pipeline, it means that when the astronomer gets the data, they can actually start at the point of doing the science that they’re interested in rather than having to do this process of cleaning up the data.

Dan: [00:09:26] And so now you’ve moved recently to the Space Telescope Science Institute and what you’re doing there is something quite similar?

Steve: [00:09:35] Right. So there, just last year I moved there to take up a position as the manager of the group, which is writing the calibration pipelines for the Hubble Space Telescope, the James Webb Space Telescope. And in the future, WFIRST.

Dan: [00:09:50] So for our listeners, Hubble has obviously been up for quite some time and still the software is getting worked on.

Steve: [00:09:58] So, yeah, the Hubble Space Telescope I believe will have its 30th anniversary this year, so it’s been up there doing science for quite some time, but there’s always improvements people are finding in how to calibrate the data. Having a much larger team and much more people looking at and working on these problems, you actually can do it to calibrate the data to much higher quality as well. And having a space-based very stable instrument also makes it possible to do much higher calibrations on it as well.

And so you can always figure out a better way to actually calibrate the data. And so we’re always constantly adding in new and improved ways to do it. Even after 30 years of operations, although the current instruments haven’t been up there the whole time – the Hubble Space Telescope did have several servicing missions – these instruments still have been in operations some of them for over 10 years now. You know, always figuring out a better way to do it so it’s a never-ending process of always actually trying to strive to get better and better.

Dan: [00:11:00] And then now I’m with the James Webb Space Telescope, which is the next big Space Telescope, which is still under construction. I think it’s, it’s due for launch when?

Steve: [00:11:11] So the James Webb Space Telescope is currently planned for launch in 2021.

Dan: [00:11:15] And can you just give our listeners a brief overview of what it’s gonna look like and how it’s going to improve?

Steve: [00:11:22] It really will be a giant step forward in terms of the next major flagship astronomical mission. It’ll be a six and a half meter telescope, and it’s actually similar to SALT in that it’ll have the primary mirror is actually segmented. So just as a SALT primary mirror has 91 segments around it, the James Webb Space Telescope will actually be a set of a smaller number of primary mirrors, which are around it, which will actually form a six and a half meter diameter.

So the Hubble Space Telescope is only two and a half meters across. The other aspect is it will be optimized for infrared observations, and so it will actually be looking at longer wavelengths than optical light. And so the telescope is actually designed to be cool to very, very low temperatures, so it can be very, very sensitive at these long wavelengths.

Well, one of the very early science drivers for JWST is actually observing the first galaxies. And because the light from these objects have been shifted redward due to the expansion of the Universe, their light is appearing mainly in the infrared. And so the hope is actually looking at this, being able to very sensitively observe infrared observations, we’ll be able to actually capture what galaxies were like very, very early on in the Universe.

Dan: [00:12:41] And a JWST is obviously another Space Telescope, but it’s unlike Hubble as it is not going to be sitting in a low earth orbit, which means we’re not going to be able to service it or make any changes once it’s up there.

Steve: [00:12:54] Correct. This is one of the reasons that it is actually very important to get it right the first time. And the telescope will actually be launched out to what’s called L2, which is a Lagrange point which will be out beyond the Earth and out beyond orbit of the Earth where we’ll actually have a stable position to be able to make its observations and be away from the effects of the Earth’s atmosphere or Earth’s magnetosphere. And so it’ll be a little bit further out where also it’ll be able to help make these observations.

Dan: [00:13:33] From a software point of view, though, I assume there’s going to be some sort of upgrade policy. You’re going to be able to do software upgrades remotely.

Steve: [00:13:42] Yes. You’ll still need to actually be able to update commands and send information to the telescope.

We, of course, need to download the data from the telescope so one of the things that they’ll have to do is actually align the mirrors. So just like SALT needs to actually do alignment of the mirrors before it observes, one of the big first challenges for JWST the overall primary mirror is being sent up folded and then it will actually unfold and then you’ll have to actually align these primary mirrors. So this process of mirror alignment will be one of the big first challenges for JWST after launch.

Dan: [00:14:25] Because obviously we need that mirror alignment to be of like nanometer precision or something?

Steve: [00:14:30] Yeah. Incredibly high precision to actually be able to return exquisite images.

Dan: [00:14:37] And we’re going to strap it to a rocket, launch it in space, and let it fold out out there on its own.

Steve: [00:14:43] Correct. Yes. The other thing is the sun shield. There’s a sun shield that will also unfurl that will help keep the overall telescope cold. And so that’s another thing that starts to happen shortly after launch with the process of having the telescope open up and be ready for doing the observations.

Dan: [00:15:10] That is going to be a stressful lunch.

Steve: [00:15:12] It is. I mean, I think there’s no launch which isn’t stressful, and it will also be a high-stress period afterwards. But that’s why people are spending a lot of time and a lot of effort to make sure it goes right. And so it’s something that you do actually want to take your time. There is actually a lot of really great people who are trying to actually make sure that this is hopefully the biggest success as it can be.

Dan: [00:15:42] And then back to the data which we started talking about your involvement with SALT. So SALT is delivering package data to the partners. What is the policy with Hubble and then JWST in terms of data packages? Are you guys doing a similar sort of a reduction first and then delivering it to whoever’s doing the observation?

Steve: [00:16:05] Yeah. Much of the reductions done by the Space Telescope Science Institute was an inspiration for what we do here at SALT. We actually based some of our early software after software that they initially developed. And also this process of and this policy of actually delivering calibrated products.

Space Telescope was really one of the first places to actually do this and they have been delivering high quality calibrated products for their instruments for a very long time. But it is actually very similar to the same process that we go through here at SALT where data is delivered to the headquarters.

In this case, it’s transmitted down from the telescope to the ground stations and then sent on to the Space Telescope Institute in Baltimore, Maryland. And there the pipelines will actually process the data. They’ll make both uncalibrated data available to the community and as well as calibrated data products as well, including combining together multiple different images to make even deeper images, removing all of these instrumental effects and actually just like the SALT data product and the HST product, they’re available to the investigators who initially proposed the observations initially. They have a time period where they have exclusive access to that dataset, but then it becomes public and available for anyone to the world to actually do science that they’re interested in doing with it.

And that’s been one of the really big successes with the Hubble Space Telescope is making their data archive public to astronomers all over the world to actually use. And so the two things are that for example, the Hubble Space Telescope has an open skies policy so anyone in the world can apply to use it. But also all of the data is open access, so once it actually becomes available to the public, anyone in the world can also use it to do their science that they’re interested in.

Dan: [00:18:07] And JWST is going to follow the same policy?

Steve: [00:18:10] Yup, JWST will have the same policy where hopefully, really the idea of getting the ideas and the proposals, and the best ideas from around the world so that anyone can have a great idea for how to actually use a telescope and we certainly hope to see some proposals from South Africa and around Africa to use the telescope. 

And then to get those best ideas and use a telescope, you know, when you have something which is this unique of a reasonable resource you really want the best ideas and the best science to be done and then to make the data available so that, you know, people can actually think of things that you never even would have first thought to look at the data to actually go and, and take a look with it.

It also makes science more reproducible because people can actually verify for themselves the results of others. Once again, it’s a been a long time policy at Space Telescope and I think that really helps the flagship missions of the Institute really produce the best science.

Dan: [00:19:19] You mentioned at the beginning that some of your research that you did when you were back here in South Africa working for SALT. Do you still manage to maintain any research time in your current role?

Steve: [00:19:33] I still do a bit of research. Not quite as much as I used to, but I still have a couple of projects ongoing, some with collaborators still here in South Africa. Particularly looking at active galactic nuclei and trying to measure their masses. And then I have some current work going on with the Hubble Space Telescope, looking at star-forming galaxies and galaxy clusters. I’m also active in a few other projects looking at different ways we can actually improve software for astronomy. Developing software packages that actually help to enable science in astronomy.

Dan: [00:20:16] Oh, these are general astronomy packages, so not specific to a specific telescope?

Steve: [00:20:21] Yup. The one project is called Astro Pi project and that is actually something I started contributing to while here in South Africa. But it’s to develop a common library in the Python programming language for astronomy. 

And from this, we have several affiliated packages that we’ve developed so that people can take these tools and then build upon them, so it’s kind of taking this idea of building on top of the shoulders of others.

So the Astro Pi projects provide some basic tools for reading and writing data for some cosmology and statistics. And then from these, you can build slightly more general tools for data reduction or spectroscopic analysis… and then from these, you can then build the tools that you actually write your paper with.

So it can be actually a very productive relationship of making it more easy to do science.

Dan: [00:21:26] It must be incredibly beneficial to students, and, you know, you’ve got guys who are just getting into the field, you don’t have to reinvent the wheel every single time you want to redo a file or something.

Steve: [00:21:37] Right? It’s something that hopefully helps everyone out of not having to reinvent the wheel. And it’s developed completely in the open so that also anyone can actually contribute, so we’ve had contributions from around the world and contributions from here in South Africa. And it’s a great open project. It’s not at all competitive, but it’s collaborative.

By doing things in the open and contributing, you’re advancing your own sides, but at the same time, you’re also making everyone else’s life easier to actually do more science.

Dan: [00:22:14] And advancing the field. I mean, you’re moving everything forward a little bit smoother, you know. Nobody’s getting caught up on writing the same old library over and over again.

Steve: [00:22:24] Exactly. And it’s one of the things that made my transition easier from South Africa to the Space Telescope Institute because they were both using the same tools.

So most of the calibration software and the pipelines that were developed were both written in Python. So some of the things, it was actually kind of nice to… we based a lot of the early SALT stuff on things that Space Telescope had actually built along with things built by other telescopes as well.

But then when I’m showing up in at the Space Telescope, they’re actually using some of the tools that I wrote here on some of the stuff that they are doing there. And so it wasn’t just going into something new, but there was some stuff that was pretty familiar.

Dan: [00:23:11] Yeah, that’s pretty cool. I mean that is definitely one of the advantages of open source code. I’ve experienced it myself in my work. It really is as you say; it’s not a competitive environment at all. It’s incredibly collaborative and everybody’s very supportive and very reactive to when you have a complaint or something’s not working, ‘Please help me’ then everybody sort of jumps in and wants to be the person to fix it.

Steve: [00:23:37] Yeah, I think also what’s great is that really anyone can actually help contribute to it. We’ve had people of a wide range of different backgrounds contribute to the project. Not just astronomers, but software engineers and also people who are doing technical writing. It also will find its use in other places as well and not just astronomy. It has been used in other science fields, has been used by the amateur astronomy community.

I’ve been doing too much astrometry lately actually. So it’s, um…

Dan: [00:24:11] What is astrometry?

Steve: [00:24:12] Astrometry is the measure of the position of stars. And so you’re actually measuring how accurate a star’s position is.

Right before I left, I was working on a group that was working on some software to improve the astrometry measurements for Hubble Space Telescope data so hopefully, that will be released soon, but I definitely have that on the mind.

Dan: [00:24:39] I mean, it’s interesting. It’s something that actually came up once before. On one of our podcasts we were talking about asteroids and tracking near-earth asteroids and their astrometry and you know, it’s dangerously close to astronomy but very different.

Steve: [00:24:56] Yeah, it’s part of overall astronomy but it’s only one of many fields.

Dan: [00:25:03] Steve, thank you very much for joining us.

Steve: [00:25:08] Absolute pleasure.

Dan: [00:25:09] It was great to chat to you and all the best with your endeavours with Hubble and JWST and WFIRST in the future. We didn’t really talk much about WFIRST.

Steve: [00:25:18] Maybe then I’ll have to come back.

Dan: [00:25:20] Great. Yeah, all the best and thank you once again for joining us.

Steve: [00:25:24] Thanks so much.

Jacinta: [00:25:37] Actually, I didn’t realize Steve had worked on Astro Pi.

Dan: [00:25:40] Yeah, that was one of the things he started here. I remember there were a lot of hack days that he did to try and develop Astro Pi when he was still working at SALT.

Jacinta: [00:25:48] Oh, right. For those listening, Astro Pi is part of the Python coding language, and it’s specifically for astronomers and it’s so good. I wish that we’d had it fully functioning when I was doing my PhD. Oh my goodness, it would have helped so much.

Dan: [00:26:08] You and me both.

Jacinta: [00:26:09] Yeah. But now it’s kind of fully functioning and it’s only since I’ve moved to South Africa a year or more ago that I’ve learned to use it. I use it every day.

Dan: [00:26:18] Yeah, it’s a great project and now it’s getting updated regularly and it’ll be used more and more by the students to make their lives a bit easier.

Jacinta: [00:26:24] Yeah, so basically I use it to read in my data, to analyze it, to visualize it, to do my whole analysis and get an answer out at the end. Do some science.

Dan: [00:26:35] Yeah, so now we’ve got these data products out of the likes of SALT, Hubble, JWST, and I guess we need to find out next how the astronomers make these beautiful images that we see. And to speak to us about that is Professor Jayanne English.

Jacinta: [00:26:52] Yeah. So we spoke to Jayanne recently and she was telling us all about… So she was visiting, uh, South Africa to work with IDIA, I.D.I.A. which is…

Dan: [00:27:04] the Inter-university Institute for Data-Intensive Astronomy.

Jacinta: [00:27:09] What is IDIA?

Dan: [00:27:10] So basically this Inter-university Institute which takes astronomical data, which these days is very, very big and hard to deal with. It puts it on a big cluster and tries to deliver it to the scientists in the cleanest easiest way.

So rather than the scientists having to download to their individual laptops, all of the data they need to analyze it, you can just log on to IDIA. And it’s through a portal and work directly on this big cluster on your data. Everything’s at your disposal. They also have the IDIA visualization lab attached to that, which helps in creating beautiful visualizations of your data, which is not just for public consumption or for fun, but actually a great way to explore your data and try and understand what’s really going on.

Jacinta: [00:27:58] Yeah, and I’m just about to work with the IDIA staff to put our data into it and examine it like that, which I’m really excited about.

Dan: [00:28:07] It’s a wonderful institute and they’re doing some really wonderful work.

Jacinta: [00:28:10] Yeah. So Jayanne was working with them on their visualization, and because she is an expert in the intersection of art and science and how to translate them to each other and how both are really essential for communicating and bringing astronomy to all of us.

So Jayanne is an artist. She has a degree in art. She also has a degree in physics and a PhD in astrophysics. So she’s very well rounded and great for this role. So she spoke to us about a supernova remnant where a massive star has gotten to the end of its life, it’s died in a big supernova explosion and what’s remaining after that is what Jayanne is looking at.

And she’s also using that and other data products to make some of the beautiful images that we’ve seen coming from Hubble and other telescopes. So let’s hear from Jayanne.

With us in the studio here in Cape Town today we have with us Professor Jayanne English from the University of Manitoba. Welcome, Jayanne.

Jayanne: [00:29:18] Thank you.

Jacinta: [00:29:19] Can you tell us just a little bit about yourself? Who you are, where you’re from, and why you’re here in Cape Town?

Jayanne: [00:29:25] Okay. I’m a Canadian and I’m a professor at the University of Manitoba in the middle of the Prairies and we have a small astronomy group there. And one of my main interests is visualization and astronomy. Here in Cape Town, the universities are interacting together and cooperating on a very interesting big data endeavour and one of the components for understanding big data is visualization, so I came to see their visualization lab and all of the experiments and visualization that they’re doing.

Dan: [00:30:00] You’re visiting the IDIA visualization, which is the Inter-university Institute for Data Intensive Astronomy. 

Jacinta: [00:30:09] Oh, well done. 

Dan: [00:30:11] I just wrote a proposal for them.

 So the IDIA Institute is set up at UCT, and as you said they’re doing some visualizations of astronomical data. So what astronomical data do you work on?

Jayanne: [00:30:25] The astronomical data I work on is wide-ranging. So I do like radio data because it’s a very rich data set. So you have velocity in that dataset. But I also do optical through infrared data. So when I’m making images, I will be making things for NASA as well. So I make images for my projects that I work on with colleagues, the science research projects and I also will make images, for example, if NASA contacts me and says, could you do an image? And the last one was radio data, radio continuum data. So there’s no velocity in those radio data sets but it was a very interesting one. It involved data from the Canadian Galactic Plane Survey and data from the Very Large Array, and it was about a pulsar. And a NASA satellite had been used for the timing associated with the pulsar, but they wanted an image to point out what was really going on and that pulsar is escaping from its supernova remnant.

So I don’t know how far back you want to go here. So maybe we should tell people what a pulsar is. 

Dan: [00:31:46] Yeah, for sure.

Jayanne: [00:31:47] Do you want to do it?

Dan: [00:31:48] Yeah, let’s do it.

Jayanne: [00:31:49] Okay. Do you want, do you want to start?

Dan: [00:31:51] Okay, so essentially what a pulsar is, is the remnant of a collapsed star. So it’s a neutron star spinning very, very rapidly, and it sends out a pulse, a beam of radiation light every time the beam crosses the path of Earth. So we measure that as a little blip, a little burst of light.

Jayanne: [00:32:19] Yeah, and it will be giving us flips in under a second. And when it forms, when the star is dying, this massive star’s dying the core of the star implodes and the outer envelope explodes. So you get a supernova remnant. It’s become a supernova when it explodes. It becomes a supernova remnant so it’s this spherical distribution around the core of the star, which is what becomes, what is, once it’s collapsed, imploded, it’s the pulsar. 

Now, this pulsar got a kick, and so it’s not in the centre of its supernova remnant. It’s been kicked out and there’s a trail of electrons, plasma flowing behind it. So it’s got this kind of little spike coming out of the supernova remnant and at the very tip of it is the pulsar.

Dan: [00:33:17] So the supernova remnant is like this cloud of expanding gas around where the supernova exploded.

Jayanne: [00:33:23] Well instead of a cloud, like a cloud in the sky it’s more like a shell. So it is gas. It’s a gas shell and it’s expanding outwards.

Dan: [00:33:35] Right. And then how would this pulsar get a kick?

Jayanne: [00:33:39] Yes, that’s the mystery. So for some reason, that explosion can be asymmetric. So it’s not sitting in exactly empty space, but there’s the interstellar medium surrounding it so the explosion can be somewhat non-uniform, not the same in all directions. And so that’s one of the ways they think it gets a kick.

Jacinta: [00:34:05] And what does this look like? You talked a lot about your work in data visualization, which I guess is seeing things right. What does it look like?

Jayanne: [00:34:14] So you can Google it.

Just Google Cannonball Pulsar and what it looks like is a shell of glowing gas. There’s some infrared clouds that have been coloured blue. They’ve been assigned the colour blue. Uh, and then you will have this little spur coming down out of the lower left side of this shell of expanding gas. And, yes it just looks like a little spur, but this is really hard to observe.

Like this needs high resolution, which they now have much better. They’ve upgraded the Very Large Array, the VLA. So you can now observe these. So I had to take the high-resolution image from the VLA and merge it in with the lower resolution survey data from the Canadian Galactic Plane Survey. So the survey data has the full shell of the supernova remnant.

Jacinta: [00:35:10] So this image has radio?

Jayanne: [00:35:12] It’s mainly radio and infrared. No optical.

Jacinta: [00:35:16] No. Okay, so you said that the image has been coloured blue.

Jayanne: [00:35:19] For the infrared. The rest has been coloured warm colours, so kind of brassy, golden, warmer, orangy almost colours. Very three dimensional looking. The shells are very three dimensional looking. There are some pinks and greens.

Jacinta: [00:35:34] so if we were to go out at night and look through a powerful telescope ourselves up in at, at this object, would we see it in blue and rusty coloured.

Jayanne: [00:35:43] No, you wouldn’t see that in any colours at all because our eyes don’t see in the radio wavelengths. So indeed you wouldn’t see it at all.

Our eyes are not good detectors, so the telescopes are much better detectors. They see in wavelength ranges, energy ranges that our eyes can’t detect. And so they’ll see in the, um… You know, if you’re looking at X-rays, you know you can’t see your bones or your co-hosts bones. You can’t see them, but you have an X-ray detector.

So our telescopes are like that. We have a radio detector, we have an X-ray detector, we have an infrared detector. So it’s all these things that your eyes can’t see. So these images are visualizing the invisible. About 70% of our brain is geared towards vision, so vision is how we grasp and understand what’s going on.

And then we measure, right? So we will select from an image where to do our measurements. So all of our data is put into visual form that we then examine. So the data from a radio telescope, actually any telescope will be black and white, and then we assign colours to it.

Dan: [00:37:00] Well, technically it’s not even black and white, right? It’s just radio.

Jacinta: [00:37:05] It’s invisible to our eyes.

So, okay I’ve got a million questions there. Dan, do you have any questions first?

Dan: [00:37:12] I was just going to say that it’s quite interesting this, and I think it’s something a lot of people don’t realize when they have these beautiful pictures on Instagram or as their backgrounds on their computers, they download these beautiful pictures from powerful telescopes.

I think a lot of people don’t realize that those colours aren’t real. And that’s your business, right?

Jayanne: [00:37:32] They are real in the sense that we’re colour-coding science, so we’re not colour-coding what your eye would see. Your eye is very misleading, and you can think of that in terms of optical illusions so your eyes aren’t sensitive enough. They’re not collecting enough photons, little packets of light, so you’re not seeing things as I just explained, because of the energy ranges, but even in your own energy range, you’re not seeing everything you could see. Even photographic film is a better detector of the light in the optical wavelengths.

So if you want to show, say what an element is, your eye will be misleading. At faint light levels, your eye does not see colour very well and things turn a ghostly green. Now we know that oxygen if you put electricity through it, is going to glow green, okay? And we know that hydrogen is going to glow red.

Now we can have a lot of hydrogen, but your eye’s going to see it as ghostly green. So you’re going to think it’s oxygen when it’s really hydrogen. So we make our measurements and we know what’s there. And then we want to say, well, what’s there? Not what your eye would mislead you to think is there, but what is really there.

So the colours are real in the sense that they’re encoding the scientific physical information.

Dan: [00:38:54] So in the visible band, we can see from red to blue and everything in between. And red does have longer wavelengths, blues have shorter wavelengths. So if you have infrared, which is of a shorter wavelength than radio.

Jayanne: [00:39:07] Yes.

Dan: [00:39:09] Would you encode the infrared to be bluer than the radio?

Jayanne: [00:39:15] That is right. And that’s why my infrared is blue in the picture.

Dan: [00:39:18] All right. So you are maintaining that sort of intuitive view of different wavelengths, but shifting it to wavelengths we can see.

Jayanne: [00:39:28] So in that particular image, yes and no.

Jacinta: [00:39:36] The plot thickens.

Jayanne: [00:39:38] So you can, for some of them, you’re using multiple datasets from different telescopes and you’ve got at each different telescope, multiple datasets that you can select from to assign colour to.

You can do that straightforward shift as a first approximation if you like. But then what you also want to do is add spatial depth and visual interest. So you can also add in some of the data sets with assigned colours that will give you spatial depth. So warm colours come forward. Cool colours go away. This is artist speak, not science-speak, right? So those are the definitions in art. If it recedes, it’s a cool colour. So in the Cannonball Pulsar, for example, I could make that look very three dimensional by using more than one dataset from the Canadian Galactic Plane Survey. 

I’m using warmer colours than the blue so I am keeping that in an actual kind of order, but I am also able to add a warmer, say, pinkish tone and a cooler greenish tone to give this Supernova remnant a very spherical feeling. So what I like to do is encourage people to use the techniques from visual art and design in order to make engaging pictures.

So the whole point of making these pictures are to engage the public so that they actually know they’re there and see them. And then the public we hope will be encouraged to go and find out more information about those art objects. So we can’t tell everything about the object in our image. It would just not be clear at all if we included everything from x-ray through to radio in that image.

You would not even notice the pulsar probably so it’s kind of an illustration in a way. Well, an illustration in the sense that even a photograph here, if I took a picture out here at SAAO, I’m taking a picture of Jacaranda in front of a beautiful white dome. I have selected that perspective, and I’m not showing you everything about SAAO, and I’m showing you a very romantic picture in that photograph, right?

So even when I make an astronomy image, there’s no way that I can’t have a perspective or context. So I am selecting things to carefully present a scientific perspective.

Jacinta: [00:42:15] And I think your interpretation, well, it’s definitely hit the mark because it was one of the reasons why I became an astronomer as I told you yesterday. I have a book called Magnificent Universe, which a friend gave me when I was 14 and it’s full of beautiful pictures from the Hubble telescope and other telescopes with gorgeous planetary nebula, supernova remnants like you were talking about before, galaxies and planets and everything. 

And the majesty of the pictures just inspired me so much that I wanted to learn more about the science and the physics behind these objects. And then I became an astronomer and you kindly signed my book for me yesterday. One of those pictures was a, was a planetary nebular I guess it is, yes.

Jayanne: [00:43:06] It’s the ring nebula. Ring.

Jacinta: [00:43:10] Ring Nebula, right? That you and your, your Hubble Heritage Team created. Now, I as a young person always thought that these were what you would actually see with your eye if you could see things as faint as that, that it was in true colour, but now you, you’re explaining that it’s not and why.

And so what would you say to someone who says that the picture is therefore not true?

Jayanne: [00:43:35] Your eye is so misleading, your eye does not see the truth.

Jacinta: [00:43:39] And so when the question is, what is truth?

Jayanne: [00:43:41] That’s right. So for the pictures that I’m actually talking about are ones that are made by professional astronomers.

So for us, our truth is the scientific truth, not the religious truth, not the philosophical truth, but what we have actually discovered we’re trying to put forward. Okay, I measured this gas here and it’s very hot, right? Which is very confusing when you do it for the public because hot for a scientist is blue and not red.

Whereas the public’s going to read it as red. So what we’re trying to do is teach them, we have some pedagogy embedded here, teach them that blue is hot, and we’re going to say this is a hot gas. And then how do you make that blue look hot?

There are a couple of different visual ways that you can borrow from art to do that. Make it glow, for example. Make it a warmer blue so that it’s more towards a greeny-blue to make it look more hot. And so you want to get the message across that I have discovered hot gas closer to the dying star in the centre of that planetary Nebula and cooler gas further out I make that a dull red further out.

But as you saw yesterday, there are many different solutions for making these images and getting that scientific truth across. You can assign colours in different ways that will do that. So there’s many very valid images to do that. And that’s another issue for the public is that they expect them because they expect it to be… if you could go up to the Hubble Space Telescope and look through an eyepiece they expect it to look like that. They’re surprised when using the same dataset they have a different appearance.

Dan: [00:45:33] They’re certainly surprised when they go stargazing to see such beautiful things through telescopes.

Jayanne: [00:45:39] But I think at the same time, when you just go up to a telescope and you see it in that ghostly green, you still have like this really dark sky behind the object. You still get a sense of 3D space and kind of blowing object in front of you, and I think people still get excited about that, right?

Jacinta: [00:46:02] What background do you have that led you to this marriage of science and art and what you call the cosmos and canvas?

Jayanne: [00:46:10] My first completed degree was in fine arts, visual arts. So I went to the Ontario College of Art and Design University. That’s what it’s called now, it was the Ontario College of Art, but in high school, I did all of the science programs. I wanted to be an astronomer since I was young. So I did three maths and physics and chemistry. I managed to avoid biology and at the same time, I had a scholarship for art on the weekends. I would go down and learn how to life draw and so on. So my interest was science, but my heritage is art. My father was a landscape painter, my aunt painted people, and so I did a lot of art since I was very young.

Jacinta: [00:47:03] In your opinion, what’s the importance of what you do of making these images, of engaging the public with the beauty of astronomy?

Jayanne: [00:47:11] Well, there’s a few things. A lot of people talk about it as giving back to the taxpayer. They can’t read a professional paper, right? So you give that to them by producing these images and they’re very curious, and it’s great to engage with people. 

But on a broader philosophical level, it’s almost like we’re creating everybody’s belief system. So most people don’t believe in a flat earth, and where does that come from? Contemporarily that comes from scientists, right?

People have an understanding that there are black holes that they exist. And where does that come from? It comes from scientists. And so we’re creating a belief system in a way. So it’s the dissemination of knowledge, but that knowledge then leads to what people actually believe about the Universe.

Dan: [00:48:07] How many people are doing this kind of work?

Jayanne: [00:48:09] There are hardly any jobs for this if that’s what you’re asking. So in terms of jobs, there’s always been about a handful, but people are absorbing it into their own practice. For myself, I’ll be working on a project, I’ll be part of a big consortium. We’ve got a nice press release coming out, I hope in November.

Our team has discovered that the magnetic fields and galaxies are kind of coming in and out of the galaxies, kind of interweaving out into space, up away from the plane, from the disc of the galaxy, but also towards and away from us. And so this is called a magnetic field reversal and this hasn’t been seen before.

Now you try and make magnetic field. That’s a real challenge. But we have this image, so it’s an image that’s created as a team. All of these are done as a team, and so instead of having a job where you go and you make these images. Instead, if you’re embedded in a group, you can be working with the group to produce images and then present them to press officers who will then disseminate them.

So the Cannonball Pulsar was one that was requested and they did not send it out to an illustrator at NASA. They said ‘Who can make this image that’s like in this paper’? And they said, ‘Oh, well, you know Jayanne. She used to work for you.’ And they say, ‘Okay, can you make the image?’ So I’m a Prof. at a university, and I just volunteered to make the image for NASA.

Dan: [00:49:45] Yeah, I was going to say, it’s quite interesting that NASA doesn’t do this in house. I would have expected them to, and it’s pretty cool that you’re on speed-dial. You’re not on Instagram with all your pretty pictures?

Jayanne: [00:49:56] Um, so when I send it to a press officer and they agree to do a press release, they put it on Instagram, they put it on Facebook, they put it everywhere.

The Cannonball Pulsar, I think had a million and a half hits last time that I asked. The place to go to is ‘Astronomy Picture of the Day’ for astronomy pictures. If you’re really into them there’s a new picture every day. And that’s as encouraging as the book that was given to you when you were 14.

Sometimes my pictures make it there, sometimes they don’t. But at my website, there’ll be a link to a Google page with my pictures.

Dan: [00:50:40] I was going to say the Astronomy Picture of the Day is quite an accolade if you can get one on there. How many do you have?

Jayanne: [00:50:46] Oh. Well, when I was on the Hubble Heritage Team for that, I was there for two years coordinating, every single one was on astronomy picture of the day.

Dan: [00:51:01] You must be the record holder,

Jayanne: [00:51:04] But that’s for the team, and the team won awards and stuff too. And then I would say some half of mine are on APOD. They have our time with radio astronomy images.

I guess this is the other thing is we’ve talked about the supernova remnant, and that’s a spherical object, and the public really understands that, but sometimes I really get tired of doing the understandable, comprehensible objects. I want to do the mysterious things, like all the gas in the middle of the Milky Way’s plain. You know, if you think of the Milky Way as an edge on a disc. You can think of it as, uh, a hamburger bun with a slice in the middle. And we, the Canadian Galactic Plane Survey imaged the slice through the middle, all the gas there. It’s very abstract and gorgeous, but you know, that’s not very comprehensible. So they don’t put it up on APOD.

Jacinta: [00:52:09] What is the Hubble Heritage Team?

Jayanne: [00:52:11] Oh, yes. So the Hubble Heritage Team was started around 1998 and it first took the data from the Hubble archive and produced images from the archival data, and sometimes we would ask for extra data from the director’s discretionary time.

One of the things we did was we interacted with the scientists who collected that data and educated them about image-making. Tried to get them onside. Scientists like contour plots and things like that and have strong opinions about how an image should present the science information and we’d have to point out to them ‘No, you don’t want it dead centre in the middle of the image because then it’ll look like it’s falling down and it’s static and so people don’t look at it for a long time.’ And so we had to educate them a lot about visuals.

Jacinta: [00:53:12] Quite a few years ago, Hubble was due to be decommissioned, but due to pressure from the public, it continued to be funded and to be run and maintained. How much of that would you attribute to some of these beautiful images that you and your team have made?

Jayanne: [00:53:30] I think quite a lot. I mean, at a certain point in time NASA had education and public outreach offices that were well-staffed. That outreach included a lot of things from video like they would make things that would go on TV. All the images are free. So if you’re an author and you’re making a book like you received, you wouldn’t have to pay for those images at all. That’s why so many Hubble images are out there. So having all these visuals being produced in a little video already that a news television station could just like grab and put up on their news show and having these pictures ready, being like shovelled out to any author who wants to use them, any news media outlet that wants to use them meant that they didn’t have to do any work to get information on science.

So these were ubiquitous and as people put it, we’re being told that this is the best telescope that was ever built. It’s the best telescope ever, and now you’re saying you’re not going to refurbish it and maintain it and keep it in orbit? Like, were you lying to us about it being this special, precious scientific instrument?

So those images, I think, played a great role.

Jacinta: [00:54:56] I mean, this is amazing and we could talk to you forever. I have so many more questions, but is there anything else you’d like? Any other final messages you’d like to share with the listeners?

Jayanne: [00:55:04] I wouldn’t be discouraged that there aren’t any specific jobs or many specific jobs in making the images, but go ahead astronomers and make the images anyway. For the astronomy students who are interested in this, get that under your belt. You can use it for your papers as well. It’s very powerful in terms of describing your research in real academic papers.

But for the public, what I would say is make some images too. Join your amateur or citizen science, local astronomy society. They have amazing telescopes and filters now about the quality we had as professional astronomers in the 1980s so it’s no longer really called amateur astronomy. It’s called citizen science because you can actually make measurements now. So join any group that’s making measurements and you can do astrophotography. It’s a really big thing, and you’ll get the hang of the science and you can present it how you like to your peers. And if you were dissatisfied and thinking that it was a false colour, then you can colour it the way you want to just to present it to people and that would be fun. And if you’re not into images, you can also do things like hunt for exoplanets.

Jacinta: [00:56:31] Yeah. There are heaps of ways to get involved. Where can people find you? Are you online anyway?

Jayanne: [00:56:36] Yeah, you just Google Jayanne English. Jayanne is J. A. Y. A. N. N. E. and I will pop to the top and I will apologize now for my old-school website.

Jacinta: [00:56:49] Well, thank you very much for speaking with us today. It’s been a pleasure.

Dan: [00:56:53] Yes, thank you.

Jayanne: [00:56:54] You’re welcome.

Dan: [00:57:05] Right. So it was wonderful to hear from Jayanne and I think to hear about how we actually get to these beautiful images. We see it’s a long process, right? So there’s all of the data processing that has to happen. After that, it gets delivered to scientists, then it gets delivered to people like Jayanne who combine art and science to try and represent this data in a way that are the human eye can actually understand it a little bit better. 

And I think it was really nice to hear that it’s not just about painting it pretty colours. It’s actually encoding the information. So velocity for example, which is just the speed the gas is moving, uh, you can encode that information and in some ways so that your art can actually see how this thing is moving. It’s really quite fascinating.

Jacinta: [00:57:53] Yeah. And I liked what she said about examining what is real and what is the truth and is seeing believing? I mean, as she said, our eyes aren’t actually that good detectors, so just because we see it in one way, does that necessarily mean that that is the truth? It’s quite a philosophical question and it’s really interesting how she’s explored that question and how she’s brought that to us through astronomy. 

Dan: [00:58:16] And as a scientist, you kind of learn not to trust your eye and you rely on things like maths and statistics and use that as a more fundamental truth not be tricked by how something looks.

Jacinta: [00:58:29] And I guess in this way, she’s using art to help with the fundamental truth. So yeah, I thought that was a very interesting approach.

Dan: [00:58:37] And that’s it for today.

Jacinta: [00:58:38] Thanks very much for listening and we hope you’ll join us again for the next episode of The Cosmic Savannah.

Dan: [00:58:43] As always, you can visit our website, thecosmicsavannah.com we will have links related to today’s episode and pretty pictures. And you can follow us on Twitter, Facebook, and Instagram at Cosmic Savannah. That’s Savannah spelled S. A. V. A. N. N. A. H.

Jacinta: [00:59:01] Special thanks today to Dr Steve Crawford and Professor Jayanne English for speaking with us.

Dan: [00:59:06] Thanks to Mark Allnut for music production, Janus Brink for the astrophotography, Lana Ceraj for the graphic design and Thabisa Fikelepi for social media support.

Jacinta: [00:59:15] We gratefully acknowledged support from the South African national research foundation and the South African astronomical observatory to help keep the podcast running.

Dan: [00:59:23] You can find us on Apple Podcasts, Spotify, or wherever you get your podcasts, and if you’d like to help us out, please recommend us to a friend and write a review.

Jacinta: [00:59:31] We’ll speak to you next time on The Cosmic Savannah.


Episode 1: SALT and Near-Earth Asteroids

with Dr Moses Mogotsi and Dr Nicolas Erasmus

Welcome to the very first episode of The Cosmic Savannah!

In this episode, we introduce ourselves and our vision for the podcast, SALT Astronomer Dr Moses Mogotsi describes what it’s like to use the biggest optical telescope in the Southern Hemisphere and Dr Nicolas Erasmus tells us about the hunt for near-earth asteroids.

The Sutherland Plateau, SAAO.
SAAO Researcher Dr Nicolas Erasmus and his MSc student Petro Janse Van Rensburg observed a large (1-2 km) asteroid passing Earth at about 75 times the distance to the moon. But in the background, a distant spiral galaxy!

The Cosmic Savannah is created and hosted by Dr Jacinta Delhaize and Dr Daniel Cunnama.

Jacinta is a radio astronomer based at the University of Cape Town. She is a South African Radio Astronomical Observatory (SARAO) Postdoctoral Research Fellow. Dan is the Science Engagement Astronomer at the South African Astronomical Observatory (SAAO).

Episode Links:
SAAO: http://www.saao.ac.za
ATLAS: http://atlas.fallingstar.com
SALT: http://www.salt.ac.za
Minor Planet Center: https://minorplanetcenter.net/

SARAO: https://www.ska.ac.za/about/sarao/
UCT Astronomy: http://www.ast.uct.ac.za/
African VLBI Network: https://www.ska.ac.za/science-engineering/avn/

This week’s guests: