hpr-knowledge-base/hpr_transcripts/hpr2397.txt

Episode: 2397
Title: HPR2397: The Urban Astronomer
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr2397/hpr2397.mp3
Transcribed: 2025-10-19 02:17:42

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This is HPR episode 2,397 entitled The Urban Astronomer, it is hosted by Dave Morris and
in about 33 minutes long and Karina Klinflag, the summary is an introduction to an astronomy
podcast that you might like.
This episode of HPR is brought to you by Ananasthos.com.
Get 15% discount on all shared hosting with the offer code HPR15, that's HPR15.
Make a web hosting that's honest and fair at Ananasthos.com.
Hello everyone, this is Dave Morris for Hacker Public Radio.
Today I'm going to introduce another podcast, which is a thing that anybody can do and give
a sample of the podcast as a recommendation to the HPR audience.
The one I'm going to talk about and present to you today is called The Urban Astronomer.
I'm interested in astronomy and listen to a number of astronomy podcasts and some of
these I've listed in the past.
This one is one that I've recently come across within the past year, I think, when I started
to hear it.
The Urban Astronomer has a website and a feed, both which I've put it in as links in the
notes to accompany this episode.
The site and the podcast are run by Alan Thursefelt, excuse me, Alan, hesitating over how
to pronounce your name because not entirely sure, but that's how I think he pronounces
it.
Alan's based in South Africa.
Anyway, I've been enjoying Alan's episodes a lot.
He does a lot of interviews with some very interesting people in the world of astronomy.
He has a really relaxed interviewing style which I certainly find appealing and join interviews
in general and I hope you'll feel the same way.
I wrote to him commenting on one of his episodes recently and I mentioned Hack Public Radio
in my email and he's subscribed to HPR.
I think he said subscribe but he's only been listening to his selected episodes and
he's also been kind enough to mention HPR on one of his recent podcasts.
So today I'm offering you a chance to listen to one of his episodes and the one that I've
chosen is number 12 from June the 16th, 2017.
It's an interview with Jen Millard who is first year astronomy PhD student at Cardiff
University in the UK.
Jen is also a host on the Awesome Astronomy Podcast and you'll hear something about that
in the episode that's going to follow.
So I hope you enjoy it.
Welcome to the Urban Astronomical Podcast.
Hi and welcome to the 12th episode of the Urban Astronomical Podcast.
I'm recording this week from my booth at the 2017 Icon Comics and Games Convention
where we are promoting Scopex, the annual telescope and astronomy expert held in Johannesburg
at the military history museum.
We're doing a lot of fun, yeah there's a full of nerds and geeks being themselves and
a lot of cosplay folks showing off their great costumes and it's a lovely vibe.
If you're in the area you should absolutely come by and join the fun, maybe come to our
stand and say hello.
We're here until Sunday the 18th at Gallagher Estate Convention Centre.
Meanwhile, as we promised last week, here is an interview that I recorded with Jen Millard
who you might already know from the Awesome Astronomy Podcast.
She's an astronomy PhD student from the United Kingdom who recently came to South Africa
to observe exoplanets through the telescope in Sutherland.
We chatted for about a half an hour about her work, about what South Africa has to offer
astronomers from around the world and the Martian heritage of her fellow podcastes
from Awesome Astronomy.
What I actually do is a very interesting question because I'm not sure what I do half the time
to be honest, but no, so I'm a first year PhD student, so I sort of did my undergraduate
degree, did my masters now start in my PhD.
So my PhD is in Fire and Foride Submillimeter Astronomy, really, using the Herschel Atlas
where the Herschel Atlas was the largest key survey carried out by the Herschel Space Telescope,
which launched in 2009, ceased to work in 2013, which was planned because it was a Fire
and Foride mission, so Fire and Foride, you're looking at very, very cool objects.
So this is one of those where it ends when the coolant runs out.
Yeah, exactly, so it was called using liquid helium, which is a temperature of 4 Kelvin,
so that's like minus 269 degrees Celsius, and as soon as that coolant runs out, it just
boils away in space, essentially, and as soon as that coolant's gone, all the telescope
can see is its own heat and its own radiation, so then it essentially becomes blind to anything
that you actually want to see, so that's why they have a finite lifetime.
Okay.
But, yeah, so I'm kind of looking at dying stars within that data, and then I'm also going
to be doing some stuff with galaxies, but I haven't really started that yet.
Then the other stuff I'm doing is all to do with extra planets, which is probably what
you want to talk about because that's why I went to South Africa.
Yeah, I was going to ask, actually, yeah.
Yeah, so the extra planets thing was a project that I started between finishing my masters
and starting my PhD, one of the lectures sort of after a types of job, and I didn't go
for it initially because I had a few holidays plans, and I thought, well, they'll just
get in the way of it.
Yeah.
But then he contacted me and was like, Jen, would you be interested and I was like, maybe,
maybe not, so we had a meeting and it sounded really interesting, so I started working on
the project over the summer, and it sort of carried on a little bit into the start of
my PhD, and then the opportunity to go observing came up, so my supervisor said, you may as
well go seeing as it's a project that you've worked on, so you have an interest in the
data, it makes sense for you to go.
So then I spent a bit of time preparing for the observing run, going on the observing
run, and then I spent a little bit of time on the data afterwards.
Okay.
So this doesn't tie into your PhD itself then, this is a next project that you did sort
of.
Yeah, this is like an extra project, so I'm still going to be working on this, but it's
going to be kind of a fraction of my time as opposed to like the biggest part of my
time, which is going to be all like the Herschel stuff and that.
But it's cool, I mean, it's always good to kind of get yourself involved in projects
which are outside of your PhD, it looks good for trying to get jobs afterwards.
It also sounds like a lot of fun, I mean, to be able to, I mean, this is your
profession, I suppose, in a sense, and well, that looks like fun, I'm going to do that
as well, and you just do it.
Yeah, yeah, exactly.
I mean, as long as, you know, the power is the B, as it were, like, yeah, okay, that's
fine, whatever, which they generally are.
I mean, as long as it's something, you know, reasonably sensible and it's going to be
good for you, then I fortunate in the, in the career path that I've chosen, that people
generally let you do what you like, which is great.
So what was the, I mean, okay, the project was about exoplanets, what specifically were
you doing?
I mean, what was it about?
Okay, so the project for exoplanets is trying to do, it's like a proof of concept, is trying
to do something which hasn't been done before, which is always great.
And so what we're trying to do is measure the phase variation part, the like of using ground
based observations, which is a whole bunch of jargon, I know.
Yes, I know.
I can see now.
I can see if I can figure this out before you tell me.
Yes, yes.
There's a massive load of jargon and it's no use to anyone, but that is like the title
as it were.
So the exoplanets that we're looking at are transsonxoplanets.
And so what that means is, when we look at the star planet system from Earth, we physically
see the planet passing in front of the star.
So we know this because we detect a dip in the light output from the host star and the
dip in the light output is regular and it's the same duration and the same sort of depth
and that that's how these sort of exoplanets are discovered rather than it being you know
an asteroid in our own solar system or something the fact that it's regular it's repeatable
that's what tells us it's an exoplanet and the exoplanets that we're looking at are called
hot Jupiters and the name is it's really self-explanatory for once in astronomy because that never
happens the name is never self-explanatory but it really is in this case so hot Jupiters are large
gaseous planets like Jupiter but instead of orbiting you know really far out from their host star they
orbit very very close to it so the stars are we the star planet systems that we've been looking at
the planets actually take less than a day to orbit their parent star which is just incredible
and we're using these systems because they exaggerate the phase curve part now
you need to kind of picture this in your mind's eye you ready we're going to draw a graph
in your mind's eye so along the bottom axis we're going to have time on the on the y axis
kind of the vertical axis we're going to have brightness right so you got maximum brightness
and then you've got like brightness decreasing as you go down yeah now when the planet passes
in front of the star as for you to me we get a dip in the light you can you can visualize that
it's like it's like a nat passing in front of a car headlight to the dip is very very small
but we can still detect it right now a little bit later on in time we get a second dip
in the light output and this isn't caused by the planet passing in front of the star
but caused by the planet passing behind the star so why is this sorry gone i was going to say
much fainter than i'm much smaller dipped in obviously yes yeah the dip is much much smaller
and this is because you're losing all of the light from the day side of the planet so if you
imagine looking at this star with this planet orbiting around it as the planet is just about to go
behind its parent star you can see all of the day side of the planet and then as soon as it pops
behind that star you lose all of that reflected light and all of that emitted light and so we get a
a much smaller but still detectable dip in the light then in between the amount of light you get
kind of slowly varies now this is how you have to picture it so you're looking at the star
if you could with your eyes without kind of burden oh no no i think i'm with you here so the
phase you're talking about is the phase of the planet as we're seeing it yes exactly and that
is the phase of the moon yeah exactly so when the planet pops out from behind the star you can see
all of the day side and then as it makes its way around it all bit so it's going to do that
transit in front of it you slowly slowly see less and less of the day side more and more of the
night side until as the planet starts transiting again all you can see is the night side and then
that slow variation in the amount of light reflected and emitted from the planet is the
phase curve and that's what we're trying to detect and i was being detected using space-based
telescopes but not ground-based telescopes right so we're trying to prove that you can do it using
ground-based telescopes and what is it useful for so from the phase curve you can get all sorts of
interesting things about the atmosphere of the planet um so you can figure out things like
has it got a thick atmosphere has it got a thin atmosphere um is there a lot of energy kind of
transmitted from the day side to the night side um things like that all right so yeah it's useful
for looking at the atmosphere of the planet all right so what instrument did you use for that
i mean what was telescope we're looking through so the telescope we use um is called the
irs f telescope so the uh infrared survey facility okay don't quote me on that
double-check just because i've gone so long now just calling it always yeah i know that i
forget what the acronym actually means um so it's japanese owned but it's based up in siddhaland so
your neck of the woods is it worth in South Africa well about a thousand kilometers away but yeah
i say your neck of the woods it's more your neck of the woods than my neck of the woods like in the UK
so but um it's a 1.4 meter telescope and it operates in the near infrared so um if anyone's
interested about the wavelength the wavelengths are around about two microns um so it's kind of
just outside what we can see uh with our eyes um it's in it's in the near infrared we do that
because the in the near infrared the difference between the planets brightness and the stellar
brightness is it's better for us because the planet is brighter in the infrared and the star is
dimmer so it just helps us see the changes that we want to see easier okay that telescope before
i seem to recall uh a presentation from one of the the engineers up there that's one of those
in there's fun little clamshell mounds isn't it's or am i thinking of another one no uh no this
one this one's got a proper dome okay and this one is the one it's got a proper dome and everything
and it's the only telescope up there with a distinctive heartbeat um i recorded that
the heartbeat so which i can actually send you that if you want to drop it in the show obviously
edit that bit out but yeah yeah right um but yeah the the telescope um has its own heartbeat and
it's it's really really distinctive um and the sound of the heartbeat is actually caused by
um the helium pumps used to cool the sectors okay um and you you can hear it for for major
so there's there's no um bathroom facilities actually in the i rs f you've got a wander over to a
different telescope to use it yeah so when you're kind of trying to fumble your way back to the
telescope in the dark it's really useful because you just listen out for the sound and then just
head for it yeah yeah it's uh is it's it's like a naughty child though that telescope
difficult for him hand mm-hmm and you like keep your eye on it it'll do what you want to do
look away for two seconds and it just goes off and does it something and yeah create easy
craziness that's so there's a very strong metaphor for me right now oh what a naughty child
yeah it always seems to resonate with people that way yeah i've got so many of them they just
so why why did you come to South Africa to do this
so um i mean South Africa is great because your southern hemisphere to begin with right
mm-hmm which means that southern hemisphere you're looking into the galaxy rather than out of
the galaxy so um when i say our galaxy i mean the Milky Way we we sit in a spiral arm about two
thirds of the way out from the center right so the northern hemisphere we're looking out through
about a third of well a sixth of the stars if you think about the whole diameter of our galaxy
whereas from the southern hemisphere you're you get the chance to look through five sixths of
the galaxy so you've got so many more stars there's so much more to see and Sutherland is a
you know a true dark sky area so um if you've ever been to a dark sky area it's it's mind-blowing
so you know it you stand up side for 10-15 minutes you let your eyes get dark adapted and
it's great to sort of go out there and and wait for your dark action to happen because you just
you know you start out and you can see the constellations or you can see the southern cross
uh all the other constellations which are in the southern hemisphere which i do not know
but we'll gloss over that yeah and uh most of them are just incredibly faint little fifth
make them two stars and they're like the drawing compass or yeah yeah yeah yeah yeah but then
you slowly start to see more stars and then the constellations get lost in all the stars that you see
and then all of a sudden you'll start seeing these these almost clouds appearing in the sky
and you realize that you know it's not actually clouds it's just lanes
and the fact that you can see it with your naked eye is just mind-blowing and in South Africa you know
Sutherland the site of the the telescope is you know it's it there aren't any
major towns or anything anywhere near it i mean there's like a little village about a 15-minute
driveway so there's basically no light pollution um and that's that's what you really look for
also because it's high up on a mountain the the air is dry um because you can't operate a telescope
anywhere that's got high humidity because you'll just get water condensing on your mirrors and
your instruments which is a massive no no um also the weather is pretty good so um generally
the site as far as i'm aware your downtime is somewhere between 25 and 30 percent so what that means is
um for any given observing when you lose about 25 percent of the days and believe it or not
that's actually quite good um you'll lose them through weather you know yeah that sounds very
good just as an amateur sitting at home i yeah that would be lovely yeah yeah oh exactly right um
i'm the seeing is generally very very good i mean while we were up there we were again sub arc
second seeing um so just in case any of your listeners don't know what one arc second is
um so an arc second is one six-year of one six-year of a degree and the moon is about half a
degree across in the sky so if you you take you take two full moons and then you chop it up into
60 bits and then you take one of those bits and you chop it up into 60 that that's a sort of
detail that you can see without the sky kind of wavering and getting in the way which is simply
amazing so yeah i mean that that's why people go to South Africa to observe well okay that's
it's so much more than i thought you're going to say well you're telling me stuff i didn't know
about about southern um yeah i mean i just assumed it's dark and it's dry and it's got good weather
but well okay so yeah there are all sorts of factors in play and you know generally i mean sometimes
you get a bit of wind coming up because it's on like a plateau so sometimes you get a little bit of
wind but there isn't really anything that's going to kind of funnel the wind um for most of the year
i mean there are points in the year where yeah the wind does get funneled and you can get gusts of
like 120 kilometers an hour or something silly like that but you know for most of the year the weather
is calm and it's good and so yeah that's why so that means it's used so how was the trip i mean
was it successful right yeah so we did struggle a little bit with weather but that's because
we're observing in winter right so that's the battle is you're either going winter to get longer
nights but worse weather or you go in summer short nights but probably better weather um so we
struggled a little bit with weather um because we had some storms and stuff and of course you lose
the night of the storm but then also a couple of days either side of the storm you get high humidity
as you know the the atmosphere is kind of preparing for this storm so um we so we struggled a
little bit with weather however we we covered pretty much all of the orbit at least twice and
that's what we were going for um and the data quality is great so although we didn't get as much
data as we wanted the data that we got is great um so i mean when i got home i spent a good week
kind of doing very basic analysis just to check out the data quality and it's infinitely better
than what we had before so before we struggled with them tracking problems but now our tracking is
within kind of three or four pixels um and that's that's great that's exactly what we need for the work
um so yeah the data looks good um those previous data was that from the same sites or
yeah it was it was from the same site and the same telescope and we think the problem was um so
i mean normally if there are any kind of asher photographers listening you'll know that you know
when you take photos you you focus so that your stars are nice sharp points that's what you want
um but what we did was we defocused our stars into donut shapes gasp horror why would you do
such a thing but there is method to our madness and that is we wanted this because we're not
concerned about pretty pictures we're concerned about making sure that our pixels don't saturate
and so by defocusing into donut shapes we could spread the light from the stars over more pixels
right to avoid this saturation but we think that because they were these donut shapes the
tracking software was instead looking for these nice sharp points and because of that it couldn't
track properly oh i see yes yeah yeah so so this time we we tightened up the focus and instead of
having nice sharp points we kind of just had blurry stars um so it was still a bit defocused
it wasn't as much as before so our light was still spread out but not over as many pixels
and that that seemed to do the trick it seemed to track so much better we've actually got people
in our in the joburg sensor of the some of my cool design images uh doing um for itsometry
with DSLR cameras and the like but yeah they've they've described pretty much what you
what you just talked about defocusing it and oh yeah there you go see i'm not making it
no no it's true yeah although they're into the tracking problem because they
they they're using separate guide cameras and and so on but so yeah yeah and i guess that
they feel the fuel be so much wider and stuff and um i mean we say tracking problems i mean
because for for our work we're very sensitive to how different pixels respond to light so um
i mean pixels don't respond to light in the same way by by factor of a few percent so for
for the average astrophotographer it's it's fine for for the average kind of study it's fine
but because the changes we're looking for are so small i mean the transit depth
the main transit can be two percent the eclipse so when the panic goes behind the star can be
half percent or less and so and the changes in between are even tinier so you know we we're very
very sensitive to any uh different responses to pixels which is why we really need to stay on
the same pixel or as close as we can to the same pixel um as possible yeah that's what we've been
able to do this time and that's why it was so important for us to be so pedantic about like which
pixel we're on sure i can just it's uh man i'm just it's so jealous to be able to track like that i
know yeah i think mine it was i tell you what when it worked it was amazing you know because i mean
well when we're taking the data as each frame is kind of finished it pops up on the screen for us to
have a look at it to make sure that you know the focus is okay you can track and stuff and it was
just so amazing to be able to see oh look it's in the same place oh look at the back frame it's
still there it's still there and oh it was great uh it sounds wonderful so well i mean that's
good that you you got decent data and got something useful don't change subject this isn't your
first podcast is it no uh yeah this is um well this is the first interview i've done for another
podcast so you can take that if you like as uh yeah world first but no so um yeah you're totally
going to plug my own podcast now because i do a do a podcast every month it's called awesome
astronomy if you just google awesome astronomy it's usually the first hit we release a podcast every
month on the first of the month we also release a sky guide and then generally some way in the
month we release a podcast extra as a little goody so we um do we i mean we do an interview we
kind of start off with the news so what's happened uh we then do an interview we've interviewed
everyone from kind of engineers through to ESA and NASA astronauts um we take questions from
people you know they email us tweet us with their questions we answer them we debunk some conspiracy
theories uh and just generally chat about space and how awesome it is so yeah if you want to tune
in do it with online it's on iTunes it's on Stitcher yeah no i'm familiar with it's i mean i've
been listening to it for oh yes now yes oh so you were listening to it before i joined because i've
only been on for like a year and a half oh yes no i was well i don't think i've ever subscribed
directly i was just sitting through 365 days of astronomy uh yes yeah oh yeah it goes out on
365 days for sure yeah well done for reminding me if you have any spare astronauts that you don't
haven't got space to interview send them over you know well tell you what you know you just
got to contact them and ask them the worst they can do is say no right right yeah i was
to say i mean Alan Bean took us like three years to get him or something because Ralph email
to him was like will you be on our show and he emailed back and he was like email me three years
and so Ralph emailed him me three years yeah to the date and then to be fair he came on and it was great
yeah i think i heard that one actually it was it was good yeah the astronaut ones are usually good
because they generally start off well and then like they're they're happy pills or something
ways off and then they go be crazy for a while and start talking about all sorts and then like
their helpers or something feed them their pills again and then they kind of come back to it but
but i think they say used to speaking as well because i think that's all they do when they come back
isn't it is interviews yeah they do talks and shows because um Paul so Ralph and Paul uh the
the co-hosts with me on awesome ashon me if anyone's wondering who the mysterious Ralph and Paul are
right um but Paul was involved with issa uh with tim peak um he was kind of an official
common boy's tied towards but he was like an official person who went around and did activities
in primary schools and things with children to kind of you know advertise it and he said that
you know when he landed he kind of had about a month to recuperate you know build his
muscles and his bones back up and then it's just a year of non-stop touring going around visiting
people giving talks um doing interviews it just doesn't stop um but he's done now all his official
duties are done so i think he's got something like six months in which you can just do whatever
the how he likes but i think it's very well deserves quite frankly yeah it must be really good for
well must be really enjoying it yes i think well it's as well well earned well deserved quite frankly
i do have a question actually about awesome astronomy what's what's with the whole sideonia thing
i mean i mean they're not really are they
oh i mean i know in other many of the trees spoken in jester and all that but
well no they are actually martians right right so i should actually show a bit more respect then
yeah i mean you know they're a bit crap don't let them hear this but they
they are a bit crap trying to invade earth so i mean every episode is a partial attempt to
invade earth and kind of control the minds of earthlings and that's what i mean they almost succeeded
at christmas christmas this year they they gave it a damn good job and they had crouch cheering
right if you want to listen to the christmas special the christmas panto
you you can hear it in there they have the crouch cheering and chanting exactly what they wanted
but once again their plans fell through because they're quite frankly idiots well the reason
well that's why i was asking because i was wondering what's taking it so long you know i've
i remain unmalisted and and and probe and whatever else they get up to so i know i mean the thing is
i think i think they they go on about wanting to invade earth and take it over but i think
they don't really want it it's almost like you know that kid who wants the toy that the other kids
got and then when they get that toy they just don't want it anymore i think that is exactly what
would happen i also thought that because you know marz is as we've seen from the rovers fairly unannabited
maybe they just lonely yeah there is that although you know they do like each other's company and they
definitely like the sound of their own voice before i get too much attention from them
what can i do to change that subject but well i don't know you can tell your listeners to
not have any fear their invasion attempts have failed 60 times so far and i imagine that they
will fail for the next 60 times oh that's a bit awkward but yeah but it provides entertainment
and it keeps them happy i mean like you said there's not a lot to do on marz you're seeing
that there's not exactly you know bowling alleys and swimming pools so that they've got we've
got to do something to keep them happy right right right well jen this has been great
thanks for coming on yeah um i can people read you if they if they want to ask you questions
i'll ask you more make friends yeah so if you want you can email me at the show at
awesomestionme.com so the show at awesomestionme.com um then i'll get them they'll come directly
through to me um otherwise follow me on twitter um so it's at jenny millard but it's jenny
spelled j-e-n-i which is supposedly Welsh but whatever but yeah so at jenny millard um
yeah they're probably the best way to get hold of me if you want to ask me any questions about
anything you know i'll do my best to answer them all right that's my ability yeah i'll put those
links on the on the show notes and uh yeah all right well thank you very much it's been great
oh thank you for having me that was jenny millard uh over Skype talking about ex-opened
observations and generally being extremely interesting and a lot of fun to talk to if you'd like
to hear more from her you can find her at the awesomestionme podcast or on social media via the
links on the show notes page if you like this episode why not drop me a line by leaving a
comment on the website at www.urban-estrimer.com or you can tweet me at you astronomer that's the
little you or you can visit our facebook page and if you're listening to this on the weekend of the
16th through the 18th of June and or in the johannisburg area well come on over come to the icon
comics and games convention and say hi until the next episode then goodbye and clear skies
you
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