Inside the Gran Telescopio Canarias - Deep Sky Videos

so this is the grand telescopio canarius the great telescope of the Canary Islands and I'm about to have a look inside with a few people it is the largest telescope on the mountain it's sort of a copy of the kek telescopes in Hawaii so it's actually uh not quite a clone but it's they started from the the design for the kek telescopes and essentially use that to reproduce another telescope it was to to for the it's a basically a Spanish telescope and it was really so that Spain could have a a really large telescope to use so we have to put on a hard hat I've got I've got a very big head my head is very big we need the biggest possible one oh wow look at that so we're in this enormous Dome and actually you can see if you look on the ground it's on this big disc which is used to rotate the teles Scope when it's in use and something else I find interesting is inside these domes they try to keep the air the same temperature as outside and quite often with telescopes just the big shutter up there you see the shutter at the top of the Dome that's the air coming in there is enough to keep the Dome cool but that also means the air comes in and out of the Dome through the shutter which you're looking through and that's no good so what they've done here you see all these rows of windows there's one there there's also rows down here at this level all these windows all those windows like that can be opened to let the cool air in so the dome's nice and cool the same as outside and the air is not only using the shutter as the way in and out so one of the the annoying things in in astronomy is that images of things in the sky get messed up by the atmosphere as the light comes down to us relatively late on it was realized that actually quite a lot of that messing up of the images was occurring very close to the ground itself and in particular some of it was even happening inside the Dome of the telescope um and really the main issue is if things aren't in complete thermal equilibrium you end up with kind of Eddy currents and things if you if you ever have a fire and you look at the air directly above the fire you can see everything is kind of shimmering and that's really just because the the the heat from the the fire is is messing up the atmosphere creating this kind of turbulence same thing goes on inside a telescope Dome if the the telescope or the ground its on or whatever is not at the same temperature as the air above it you end up creating these turbulent effects so what you want to do is you want to get everything into thermal equilibrium as quickly as possible you want the telescope to be the same temperature as the air to be the same temperature as the ground and so on and so we've done quite a lot of things now to try and and make that happen as quickly as possible so we don't waste time so for example quite a lot of telescope domes now the floor is actually refrigerated they actually use that to bring the the floor down to the same temperature as the air keep it in in equilibrium with the air but of course a relatively simple way of doing this is just have plenty of air flow through the telescope so that you take away any air that's warmed up you bring the cooler air in everything just reaches thermale equilibrium that bit sooner so these shutters are really just to get a good air flow through the telescope so that everything ends up in thermal equilibrium so the light comes in the shutter and then it comes down to the mirror the mirror is just see those dark pieces there there there's one see those dark pieces they make up the mirror there are 36 of those pieces and they're all combined together to make this 10.4 m diameter mirror people have tried very hard and come up with very clever ways of me building mirrors up to about 8 m in diameter incredibly hard work to do but you can just about do that but that really is pretty much the limit of a monolithic mirror a single mirror and so if you want to build a telescope that's any bigger than that you actually end up building not a single mirror but a segmented mirror a mirror that's made up of lots of individual segments so the the grand toan telescope is is one of these segmented mirrors it's a whole set of hexagonal segments that all together uh are arranged to form the kind of the single mirror of the primary so 10.4 M that is massive that is a huge mirror one of the world's biggest so the light comes in through the shutter which is closed at the moment hits that big mirror and then actually it bounces back up to that thing there that's the secondary mirror the light hits the secondary mirror and then it bounces back down I'll show you what it hits next it bounces back down and and goes into that black tube there and then the light can actually go off to this side or it can go off to the other side into the instruments where the measurements are made this is I cannot tell you how big this thing is you really have to be here I've also just been warned not to step on the disc there that the telescope's mounted on cuz that's actually floating on oil and if I step on that it will actually move the telescope and at the moment they're working on the mirror and uh if they're working on the mirror and then I Shake It by stepping on the disc that will make me incredibly unpopular there's a better view of the shutter now that's the shutter my hat fell off there's actually desks under the telescope on the disc desks with computers I took a great photo of this telescope the other night there was a cloud hovering above it for hours so they're letting us go up these stairs now so we can look at the telescope from up a bit higher there's the astronomers posing for pictures with the telescope even astronomers are impressed by this okay so we're upper level now we're on this walkway you can see we're on a walkway around the Dome got a better view of the secondary mirror now and we're almost up at the same level as the primary mirror the mirror that's made of those segments but we're still not quite high enough to look down on the mirror and there's those areas on the side where the instruments get mounted and if I go here you can sort of see a bit better now how when the light comes from the secondary mirror it comes down there and then can shoot off to the side you can even see where it comes out see so they've given me the okay I'm going to walk all the way around the walkway so we're underneath one of the sides where those instruments get mounted they can put some huge instruments on here if you're used to telescopes being those small things in people's backyard think again oh now look here from here we've got a nice view of where the light goes into the instruments see it's come down and then gone in there looking down there as well we got a nice view of the of that disc floating on oil that the telescope's on again there we're sort of seeing those segments that are put together to make the mirror 36 of them each single one of those 36 would be a dream for most astronomers I've got 36 of them to make this combined 10.4 M diameter I'm glad I'm wearing my hard hat but I think if this fell on me I don't know it would do me much good and there's May bit of a tourist shot with the telescope I I've never been in the the Dome I've been there obviously it's taken a number of years so I've watched the Dome kind of coming up from the ground and so on so i' I've watched it growing up um but one of these days I really must get inside and have a look around you can just watch the video there she is from the outside you can see those windows I was talking about so there's the shadow of the Dome and check out that view there are various things that you need to think about when you're cting a telescope one is for example you want a nice dark site but of course on the other hand you don't want to be too much in the middle of nowhere because you've got to get people out there you got to get electricity there and so on so the there's lots of trade-offs one of the trade-offs is that that you need people around in order for actually there to be enough infrastructure to build a telescope but not too many people around so that the the night sky is nice and dark but one of the other issues is obviously one of the good things about being up a mountain is you're above clouds and so on but if you build up a mountain in the middle of a mountain range typically the air would have gone over the tops of other mountains before it gets to your mountain and one of the things that happens to air you know air typically starts flowing in a nice laminina way nice smooth flow when it encounters a mountain top it becomes very turbulent and so if you're kind of on one of these Downstream mountain tops you end up with all this turbulent air from the other mountains going over your head and turbulent air creates this phenomenon of seeing which messes up the image quality of what you can actually see in the sky so the perfect Peak as far as an astronomer is concerned is a peak which is on its own and that's why islands are so perfect because you've got all this ocean around them which means that the air has had plenty of time to calm down and be in this nice smooth lamina flow and then there aren't other mountains around which would have messed up the the air flow over your Mountain so that's why so many of the Premier observatories like LA and Hawaii are mountains high mountains but that they're isolated in the middle of the ocean not bad have you oh yeah not bad not bad not bad it's uh it's quite big I still prefer that one over there you prefer those ones yeah that's my preferred one that's the William hersel telescope that's right that's part of the Isaac Newton group of telescopes that harier works for but but that's not bad either that's not bad we're so high up here that you're normally above the clouds and that's a good thing when you're doing astronomy look at them they're astronomers being tourists they love it taking their photos at night they take photos of space but they can't take a photo of themselves for toffee getting the sunlight boys next to the telescope they have all these levels here this was actually used for the inauguration of the telescope all the VIPs were sitting here not a bad view they had hey you'd think all the telescopes up here have pretty much the same view but actually each site has slightly different seeing conditions they actually chose between that site there and this site here and they must be only a couple of hundred met apart maybe 300 M but all the testing they did showed the seaing conditions here were ever so slightly better than the seing conditions just over there which is actually a little bit higher the other irritating thing is that things vary with time so what's a beautiful site one year will turn out to be a rubbish site for the next 10 years which means that if you're not really careful with your sight testing you can fool yourself into thinking this is the perfect place for my telescope you just happen to have caught it done your sight testing in the one year where that was the perfect place and for the next 10 years it turns out you'd have been better off 100 yards up the road here's another interesting fact I was saying before how important it is to keep the telescope Dome cold and over the years they've realized one of the most important things to do is keep heat sources away from the Dome don't build anything that generates heat near the Dome and that's why in modern telescopes like this all the engines and heating stuffs right over there far away as possible from the Dome I I grew up in London and so actually I I had rarely seen the night sky at its best until I went to started going to professional astronomical observatories I'd never seen the Milky Way um and so going out in a place like Lea in the middle of the night and just looking at the sky and seeing this band of light across the sky sometimes the Milky Way is so bright I swear I can see my shadow from the Milky Way it really is that impressive across the sky and I've been out there for some of the meteor showers few years ago I was out there where one of the big comets was flying across the sky and you could see this tail of this Comet across maybe a third of the sky it was so dark it's absolutely beautiful and you know you do you'll often find if you go observing with professional astronomers we're pretty Blas about the night sky but nonetheless you'll find that you know once or twice a night we'll sneak out just to have a look at the sky because it is so gorgeous

Channel: DeepSkyVideos

Views: 54,496

Keywords: GTC, La Palma, Gran Telescopio Canarias, astronomy, astronomers, messier, space, galaxies, nebula, nebulae, stars, universe, deepsky, deepskyvideos, deep sky, telescope, Messier, Messier Objects, Messier Catalog, Messier Catalogue

Id: 9YgACusQaTE

Length: 12min 25sec (745 seconds)

Published: Thu Feb 16 2012