Good evening and welcome to The Sky At Night from a most unlikely venue,
Regent's Park in London, within a stone's throw of the zoo.
Well, people have been sloping around enjoying the sunshine. That's gone now.
Dusk is falling and it's time for the astronomers to come out to play.
Pete Lawrence, Chris North and Paul Abel
are joining me now for this most improbable observing session.
Here we are in Regent's Park. I'm hoping for a look at Saturn tonight.
Pete, what are you hoping? You'll be lucky.
Look at this weather. It was clear when we arrived but now...
It's Selsey clouds. It's not Selsey clouds.
It was drizzling in Cardiff so it's an improvement. What are you hoping to see?
I think some of the deeper sky objects, if it clears enough
to see those, it would be nice.
'This is the first time I've tried astronomy from a big city.
'Things I'd like to look at are M13,
'a wonderful and ancient globular cluster,
'containing thousands of stars
'and Bode's Galaxy, or as you might better know it, M81. '
'The Baker Street Irregular Astronomers formed last year
'and try to meet every month when the skies are clear.
'While we set up the telescopes,
'Patrick is finding out more about this new society from Tom Kerss. '
First of all Tom, why are you called the Baker Street Irregulars?
Well, in Arthur Conan Doyle's classic literature,
which featured Sherlock Holmes, there were these incidental
characters called the Baker Street Irregulars, and they lived around
Baker Street and they would go into Regents Park and do
all sorts of investigation for him,
so that's where the name Baker Street Irregular Astronomers comes from.
What about light pollution? Pretty horrendous?
It's pretty bad but we can get around it.
There's a lot of people in London and the way we see it,
why not at least try to make
the best of what we've got?
Which is a surprisingly good amount after all. How do you get round it?
Sometimes we filter it out. There are filters which help
you to visually observe through light pollution,
but quite a lot of the time what we do is simply ignore it.
We observe things that are above the light pollution or we just accept that
the light pollution is always going to be there,
limiting our observations, and make the best of what we've got.
What about telescopes? What are the smallest and largest?
I'd say the largest telescope we've had set up here is a 16 inch
and the smallest can go right down to the kind that I use,
which is actually less than three inch.
We can do observations of anything in the solar system really,
anything that's sufficiently bright.
So we'd be looking at the planets,
maybe the moon, some asteroids and also the sun during the day.
Tom, thank you very much.
With darkness approaching more astronomers arrive to join the party.
Unfortunately the clouds are hovering above us.
But we're hopeful that they'll clear later.
There are also an amazing number of telescopes to look at,
but nothing beats a good pair of binoculars.
Ah, the perfect instrument for looking at the moon.
How big are those, Carl?
These are 15 times magnification.
OK, 15 times, so you'd be able to pick out
the dark patches on the moon,
which are the lunar seas, the maria,
of course there's no water on the moon at all,
they're just frozen lava basically.
You should also be able to see some fantastic craters, Tycho,
that ray crater, have you seen that?
You can see it fantastically, the craters,
the shadows come out nicely.
When you've got a phase on it you get that lovely line down the terminator,
the bit which divides the light to the dark,
and you get the lovely craters there and the mountains as well.
Absolutely amazing. Absolutely.
I think binoculars are ideal.
They aren't expensive, they're portable
and they prove that astronomy
doesn't have to be cumbersome or expensive.
Well, all sorts of telescopes on show here.
Ralph, this is a nice telescope. What size is it?
This is a 90mm refractor, so it's a nice sort of smallish telescope
but you get plenty of light gathering.
Yeah, yeah, it looks very impressive.
What are the things you like to look at?
Well, I like the big deep sky objects,
I like the Andromeda galaxy, being able to see
a galaxy in its entirety,
the Orion's nebula which is always beautiful,
but it's also fine for looking at the planets.
At the moment we've got Saturn, and Jupiter recently.
The moon pretty impressive as well. Beautiful over the weekend, yes.
I see you've got all sorts of paraphernalia attached to it.
This is a go to system. It's nice and easy to use.
Once you've got aligned you can just move the telescope on it
and it'll find any object you want to,
so even if you don't know anything
about finding your way around the sky
this will do it all for you.
This looks quite portable, which I'd imagine is quite useful
if you're coming down to a park.
How long does it take to set up?
I'd say probably, to put the tripod and the telescope on it takes about
five minutes and then another five minutes to get it aligned.
Astronomers crave dark skies
and every photon of light counts
when you look up at the sky, whether it's at planets in our solar system,
nebulae of all kinds, or distant galaxies,
each an island universe containing trillions of stars.
Satellite maps of Britain from space
show how light polluted our island is, especially London.
The orange sodium streetlights are the main culprits,
but even in the orange haze of light polluted London,
these astronomers don't feel excluded or deprived.
They can still see these objects by using a few tricks of the trade.
As astronomers the one thing we really don't want is light pollution.
Indeed. It gets in the way.
In the middle of London that's exactly what we've got.
Indeed, you look at the clouds,
they've got this nice orange tint to them
which is them reflecting the street lights
which are predominantly orange, and even if you take away the clouds,
the air behind, the atmosphere behind
also reflects the orange light and that gives an orange glow.
It'll decrease higher up. If you take a long exposure photograph
for example, of the sky, it would just come out orange,
but there's a way around that, isn't there?
There is. You can use filters to block out some of the wavelengths
of light that are caused by street lights.
There's a particular kind of filter
that will block out that orange glow
which is a very particular wavelength caused by sodium streetlights.
It's like peeling the orange layer away so you're looking beyond that.
Where would the filter fit? Not on the front of the telescope?
These fit on the eye-piece end.
They just fit in at the front of the eye-piece here.
In fact, eye-pieces are actually threaded, they have what's called filter thread in them
so you can get this filter and screw it on to the eye-piece
then put it into the telescope and then away goes the orange.
That's not the only type of filter you can use, is it?
There's another way which looks at just the wavelengths
that we want, so if you're looking at a deep sky object such as nebulae,
you're mostly only looking at specific elements and molecules,
so it might be things like sulphur and oxygen and hydrogen and so on.
It brings out the real detail of the nebula that you're looking at.
It only lets through those wavelengths that we really want,
blocks out all the rest of the background light caused by the city and the towns around, so it just
gives us a much clearer view.
So the final story is that if you have light pollution, don't give up on looking up.
Not at all.
'The clouds have parted briefly and we get a glimpse of the super moon,
the largest full moon since 1992.
'While it's simply the effect of the moon's slightly elongated orbit
'many of the Irregular Astronomers have come along to Regents Park to share this lovely sight. '
Well, Adrian, this is certainly a substantial telescope.
Uh, what size and make is it?
This is an eight-inch LX90 Schmidt Cassegrain telescope, Paul.
That's quite different to the refractor we were looking at earlier.
With the Schmidt Cassegrain the light comes in here from our object,
it hits the primary mirror here then goes back up to the secondary
and finally travels all the way down to the centre of the tube to your eye-piece here.
There are some benefits to this type of design.
That's right, Paul, that's correct.
As you bend the light path it increases the focal length,
so it makes this tube effectively a two-metre-long tube.
So, I've got a lot of power for studying close-up detail
on the planets and the moons of Jupiter and Saturn.
Is the moon and planets something you look a lot at?
Oh, I follow Sir Patrick a lot and I am very much a lunar observer
and this allows me to study things such as transient lunar phenomenon,
which are those very strange flashes we sometimes see.
I have yet to see one officially. Same here.
But keep looking and of course the planets as well,
we've got Saturn around at the moment, I should imagine Saturn is quite nice.
Yes, a little bit later I'm going to go for Saturn, when she rises,
and hopefully we'll get a nice view of the Cassini division
and hopefully those storms. Yes, they should be quite bright tonight.
Midnight is approaching and our star party in Regent's Park is still busy.
As a reward, we get a brief tantalising glimpse
of Saturn and its moon, Titan, before the clouds roll in again.
Through a small three-inch telescope you can see Saturn and its rings,
but it'll look a little fuzzy.
Nevertheless at a billion kilometres away,
that's still a great view of this gas giant.
A larger telescope, such as an eight-inch,
will give you more detail of the planet,
and most importantly the rings.
The dark line around the middle of the rings
is called the Cassini division. Once thought to be a gap,
we now know it's filled with dust and small rocks.
And if you look closely at the top of the planet you can see a small fuzzy
patch which is an enormous storm raging in the planet's atmosphere.
Simon, I'm glad you're here.
This is a most impressive telescope.
It is indeed. This is a 16-inch reflector,
similar in capability to your own 15-inch.
It's a Dobsonian. It's a Dobsonian, so it's a very portable instrument.
For deep sky, isn't it, really? It's for deep sky
but you do get stunning views of the planets as well.
Did you know, by the way, there was once a major observatory here on Regent's Park?
I didn't know that, Patrick. I'll tell you the story.
It was set up by a Mr Bishop in 1840,
and actually the first visual confirmation
of the discovery of Neptune in 1846 was made here.
We're here to continue the trend, hopefully.
We are indeed, on historic ground.
Simon, thank you very much.
We called it the Double Star programme and there's another
Double Star party, so now over to Chris Lintott.
From Andromeda to Corvus, from Hercules to Puppis, all the way
through to Vulpecula, there are 88 constellations in the sky.
But today, 88 is a special number for another reason -
it's Patrick's 88th birthday,
so of course we've come down here to Selsey to join the party.
This is Patrick's own private birthday party in his home in Selsey.
All his friends are helping to get the marquee ready
for his special guests, who will be arriving later this evening.
People are flying in from all over the place,
from South Africa, from Finland,
but most have travelled from all over the UK.
Many have brought their telescopes just in case the clouds clear.
It's a double celebration because Patrick is also marking the 700th programme of The Sky At Night.
It's a celestial alignment that he'd like to share with everyone.
So, Patrick, happy birthday, happy 88th birthday. I feel very old.
Well, not that old I hope, but from the 88 constellations which is your favourite?
I'll go for Crater.
OK, why? It's fairly obscure.
It's a nice little constellation, a nice red variable star there - Arcanus.
OK. And how would you find Crater in the sky?
With some difficulty!
To illustrate our 88 constellations,
what could be better Uranus' mirror. This collection might
date back to 1825, but they're still beautiful drawings today.
To get things going, we thought we'd ask everybody for their favourite
constellation, but for Pete and Paul we've got an extra challenge -
they've got to name all 88.
So, Pete, name a constellation.
Do you want them in alphabetical order?
If you can, but I'll take any order.
No, we don't want that, Pete!
Taurus. Taurus? Why Taurus?
Because you've got two wonderful clusters in there.
You've got the Pleiades cluster and Hyades cluster
Most interesting objects to observe and image.
Oh, it's got to be Pegasus. OK, why Pegasus? Well, well...
winged horse, flying through the constellations.
When you have Pegasus up then you also know your Andromeda is not too far behind. OK.
Corvus. Corvus. Ara.
How about Canes Venatici? Why?
Uh, because of M51. Beautiful.
Apus. Pete's going to be good at this, I can see.
I only know about four constellations.
People ask me, "What's that bright thing in the sky? "
and I say, "It's probably the moon. " Or Jupiter, sometimes it's Jupiter.
Sagittarius.
The interesting thing about Sagittarius is what's behind Sagittarius.
Out the back is something I discovered, the Sagittarius dwarf galaxy.
Of course. Now become incredibly famous.
It was the first discovery of a galaxy actually merging into the Milky Way.
So the Milky Way is actually eating up this galaxy and we're observing the way the Milky Way grows.
Patrick. Hello.
Happy birthday. Oh, thank you.
A small greetings card.
How about Libra? Can I have Libra? Yes, you can have Libra.
You have to explain why. Well, it's my birth sign. OK.
Probably Cygnus, this one. OK. Because it's a summer constellation
so sitting out and observing it is a comfortable thing to do
apart from anything else. There's some beautiful nebulosity in it.
North American Nebula, Pelican Nebula.
Of course, the whole of the Milky Way runs though it.
So, it has everything. Great.
There you go.
Canis Major. Canis Minor.
I'll take Octans.
No-one has Octans. Why Octans?
Well, it's a miserable faint Southern Hemisphere constellation
but the great thing about it is that it contains the south celestial pole.
Just because it has one of my favourite objects in it at least
it would probably be Ophiuchus. OK. What's the object? RS Ophiuchi.
Oh, your nova. Yes, a recurrent nova. OK.
Ah, Patrick. Happy birthday to you. Thank you so much.
Thank you for this wonderful party. We have some things for you.
This is an image of Victoria Crater on Mars.
Which, when you look closely... Ah.
.. it has you just superimposed.
THEY LAUGH
It doesn't end there.
That's you as if you had... joined Apollo 16. Ah!
And taken your wonderful telescope with you. Thank you very much.
It's a great pleasure, Patrick.
Microscopium. The world's worst-named constellation, yes.
Antlia. Antlia.
It's Puppis. Puppis? Yes. Have you ever heard of it?
I've heard of Puppis, I'm not sure I can find it in the sky.
It's an anonymous one except for one thing.
Actually, I wrote my PhD thesis on an object in Puppis. OK.
It happens to have one of the brightest
soft X-ray sources in the sky.
So, in the X-ray sky it's very bright. Absolutely.
Patrick...
Happy birthday. Thank you.
Carina.
Triangulum.
Orion. Orion.
Absolutely,
besides which the Nebula. It's a fantastic object.
If you want to impress someone quickly without having to do too much fiddling.
It looks like a nebula.
Have we had Dorado? I don't think we have.
No, you can have that, the goldfish. Octans. Octans.
I was going to have that!
Scorpius gives me a great twinge of excitement because you can only just
see it from the British Isles and if you're lucky enough to ever go
to Africa or South America suddenly you see Scorpius high in the sky
and it's tremendous, it's very sparkly.
Oh, we're doing the southern sky.
Have I had Vulpelcula. No-one's had Vulpecula.
Going to go for that, Equuleus. I'm going for Scorpius.
Scorpius, why? Well, that's my star sign.
OK. Don't let Patrick hear you say that.
No, no. Well, Scorpios don't believe in astrology. OK, excellent, very good!
Ooh, a power cut. Oh, wow.
My goodness, this is live television!
I know my constellations as much as a doctor knows the telephone numbers of his patients,
but nevertheless, I do have a favourite constellation.
Go on, then. That's Fornax. Fornax?!
Why Fornax?
It's named after a Roman goddess who was extremely good-looking. OK.
Secondly, that's the location for the ultra deep Hubble field
and therefore it contains the most distant galaxy known.
Present for you, Patrick. Oh.
My textbook, finally. I'd like you to have a copy. Thank you so much.
I've written a little dedication in the inside. Thank you so much.
Cygnus. Lyra.
Mine's Canis Major. OK. And that's because I'm interested in Sirius.
The brightest star in the sky.
What always appeals to me is that Sirius is hiding in its glare.
Also the brightest and nearest white dwarf.
And most people don't really know that.
And, of course, it's easy to find! It is, you've got the brightest star.
I pick Taurus. Ooh, that's a good one.
I've chosen the constellation of Lupus. Lupus!
Lupus the wolf. Why on Earth?!
The lesser-known constellation
in the southern hemisphere, but a marvellous star-forming region.
We've been taking many pictures of it
with the Herschel Space Telescope.
George, do you have a favourite constellation?
Yeah, Cassiopeia. Cassiopeia, why Cassiopeia?
Because we named our dog that. OK, good reason.
Derek, George. Cassie for short. Excellent.
Oh, I had a cat called Bootes, so Bootes. OK, the herdsman.
Definitely. I have cows as well!
There you go. An even better reason! That sorts both.
Er...
Oh, now I'm starting to struggle.
There's 22 that begin with C.
That's great, you've both won the motorboat!
Come on, no, you can join the party.
No, that will do!
Congratulations and happy birthday. Thank you so much.
Almost everyone I spoke to seemed to pick Orion but it just goes to show
that some constellations are familiar friends
and others we have to search out.
My personal favourite, Crux, the Southern Cross, I had to wait many years to see when I travelled
down to the southern hemisphere, but there it was glinting in the sky
just as I always thought it would be.
That was a very enjoyable party.
Back now to me in Regent's Park in the middle of London
with the Baker Street Irregular Astronomers.
It's Nick, isn't it? Yeah, that's right.
Hello, Nick. This is my kind of telescope, a nice big telescope.
Now, the clouds have actually started to disappear a bit so we can actually see some things in the night sky.
And you're looking at Saturn?
We were looking at Saturn which is currently obscured again
but we're going to try for the moon in a little bit to see some detail on the craters.
That moon down there is fantastic because it's above the light-up tower, what a sight that is.
What have you seen on Saturn? We've seen the Cassini division on it,
we've seen several moons.
That's quite impressive. From central London. Yeah.
The aperture helps, so.
Of course. How big is this? 12-inch. 12-inch. Right, OK.
That is really quite impressive, actually.
What would you normally use this one for? Are you planetary or lunar?
I do like deep sky more than anything else,
but living in central London it's a rarity.
I need to take it outside of London to see that.
From my back garden I love imaging and watching the moon
in this and any kind of planets which happen to trundle by.
Hopefully, April should be a good month for a observing.
The spring constellations of Leo and Virgo
contain many lovely deep sky objects.
But first we go to the planets with Pete and Paul.
Plenty to see in April even from inner-city regions like this.
Saturn for example. Absolutely.
Saturn comes into opposition on 4th April
which means it's in the opposite part of the sky to the sun.
It's up all night.
Opposition is the time when Saturn is at its largest
and brightest in the sky.
It's the only planet in the evening sky. All the others have vanished.
They're all noticeable by their absence, but they haven't gone away.
They've all gathered together in the morning sky.
They're all going to gather together at their utmost next month.
You can see the start of that this month. If you've got really clear
skies on 30th April and you go out just before sunrise, you'll have a beautiful view.
You'll have the crescent Moon,
then you'll have a bright Venus and then Mercury will be visible.
Very close to the horizon you'll have Jupiter,
very low down, but still quite bright.
Look at Jupiter and you'll see the little planet Mars.
Mars is making a comeback and will be getting quite large towards the end of the year.
Do you see a great deal at this sort of time? No, it's really tiny at the moment.
Very difficult to see.
Moving on from the planets, we have the moon.
You've found us a nice lunar crater this month, haven't you?
Yes, Theophilus, one of my favourite craters.
It is lovely.
The best time to see this crater
is when it's very close to the terminator.
The bit which divides the bright bit of the moon to the dark bit.
And if you go out on the evening of the 8th of April, that's a really good time to see it.
Are you going to image it? If it's clear.
I did once try to draw it but I gave up after a couple of hours, too much detail!
That's not the only thing, we're in springtime now and springtime always means galaxies.
The Earth turned away from the galactic centre, looking out into space.
We can look at others. In particular M65 and M66 in Leo.
I love those, in the back leg of Leo.
One is the Leo Triplet, in fact.
I have picked these up in dark skies, I should stress, with binoculars.
They're not close. Remarkable. It is. They're a long way away.
Not local, really. M65 is 35 million light years,
M66 is 36 million light years. I always think it's remarkable you can see these distances
with just a pair of binoculars.
It's getting late and it's just the die-hard astronomers left.
Had we had a break in the clouds, I had hoped to see the Orion nebula.
Located in the sword of Orion, just below his belt, the nebula appears as a fuzzy patch through binoculars.
Small telescopes will show a brightening
due to the hot, young stars burning in the centre.
Larger telescopes will show the structure of the nebula itself.
Meanwhile, we have breaking news from our solar system.
NASA's venerable Stardust spacecraft has used up the last of its fuel.
Stardust flew past comet Wild 2 in 2004 and brought back
our first samples left over from the early solar system.
Its last close encounter was in February this year
when it whizzed past comet Tempel 1
and saw the tiny scar left behind by the deep-impact collision.
Stardust has been an enormously successful mission
which has travelled six billion kilometres and brought us closer to understanding our solar system.
We also have news from Mercury.
Dave Rothery from the Open University has joined us to tell us more.
Dave, may I come to you first?
Very important news, the Messenger probe is now in orbit around Mercury.
This is wonderful. Messenger is the first probe ever to go into orbit around Mercury.
It's had three fly-bys already on the way there, the last in 2009.
Now it's in orbit. Finally we'll get a complete map.
We've covered 95% of the surface already between Mariner 10 and Messenger.
Most of it's only under one set of illumination conditions which isn't great
because as you know from looking at the moon, the full moon
and no shadows makes a big difference.
Different information under different illumination conditions.
Messenger will be in orbit for at least one Earth year
mapping the whole planet, hopefully an extended mission of a further year beyond that.
Not just imaging but laser symmetry, map topography,
and various instruments to try and measure the chemical composition of the surface as well.
It will be a fascinating planet to find more out about.
Obviously, that's going to take some time. Dave, let us know when you're ready and the information's in
and then we'll do a full Sky At Night programme. Absolutely.
Moving on from Mercury, let's turn to Saturn and its largest moon, Titan, and the rainfall there.
These are observations from the Cassini spacecraft
which has been orbiting Saturn for some time now and it makes regular fly-bys of its largest moon Titan.
We know it's covered in a hazy, methane atmosphere.
It has a cycle very similar to the water cycle on Earth.
We've seen lakes at the poles on Titan and as the seasons
are changing we've seen this weather activity move
towards the tropical regions, further towards the equator.
We've seen much more equatorial activity than before.
What's being seen now is cloud,
presumably methane clouds low in the atmosphere near the equator.
When the clouds have moved away they reveal a surface that's
darker than it was before, presumably meaning wetter.
It looks like it's rained under these clouds which is great.
There are dry valleys near the equator
which we saw as soon as we got to Titan, but we didn't know
how long those valleys had been dry for. It could have been thousands of years.
But it now seems likely that every year at this time of year it rains.
Methane rain? Methane rain and there are probably methane
rivers even as we speak flowing down some of these formerly dry valleys.
This is all cos the seasons are changing.
The year on Saturn is much longer than here, it's 30 years long.
30 Earth years long. We've just passed the equinox,
the autumnal equinox in the southern hemisphere,
and Cassini is now going to stay orbiting Saturn until 2017 by which point it will have gone
from one extreme of the seasons to the other.
So, almost 15 years in orbit and we've seen almost half a year
so we'll get a much better picture
of how the seasons affect not only Saturn but its moons.
Finally this so-called "super moon".
The moon goes round the earth once every month
and the orbit isn't quite circular
so every month it reaches what we call "perigee".
This closeness to the Earth. This is as close as it can get.
The Moon is full at the same time and very high up so it appeared very brilliant.
It had absolutely no effect on anything.
The change of the apparent size of the Moon in the sky is something
like 10% in all as it moves closer and further from the Earth.
The effect is miniscule.
It doesn't cause earthquakes or anything like that.
All nonsense generated by the press, fortunately.
But it's given lots of cause for some lovely photographs people send in of the full moon
in its splendour.
These can be submitted to our Flickr account on our website.
People can submit them and see other photos that people have sent in.
Dave, Chris, thank you very much.
Thanks also to those who have taken part in this programme
and to those who founded and built up this excellent society right in the middle of London.
Meanwhile, don't forget,
it's Newsletter time.
The website contains extra, fascinating information.
So all good things come to an end. It's been a fascinating evening.
When I come back next month, I'll be talking about Saturn.
Until then, good night.
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