M31 - Andromeda Galaxy - Deep Sky Videos

what I have to start with is this book here called the story of the stars by GF chambers fellow of the Royal Astronomical Society and it was published in 1903 and if you just open to the front page it's got this beautiful picture here and the book says there is one elliptical nebula which stands out beyond all the rest yet it's great sized brilliancy and peculiar features forbid it being regarded as a typical elliptic nebula I am here alluding to the great nebula in Andromeda Messier is 31st alright next time something exciting is that what do you got for us well if you are the sky conditions we've sort of been battling with all night it's always a good thing to image something bright and one of the very brightest deep sky targets is of course m31 the Andromeda galaxy and this has been imaged by just about everybody who's ever pointed a telescope at the sky with a camera attached the tusks up in a way is almost too powerful so we only get the central part we'll take a snapshot image this is just to place the target on the chip and then we can concentrate on taking a longer image after that to pick up some of the dust lanes of all the Messier objects surely this is the big one it is both metaphorically and physically actually it's huge on the sky it's actually about five degrees across it's called galaxies don't have sharp edges so you can't say exactly where it ends but if you think about it the moon's about half a degree across so this is ten times the size of the full moon across the reason why you don't see it booming out at you in the sky is because it's very very faint you can just about see it with a naked eye but not a little bit so as with most galaxies its brightest in the middle and then fades out so you can just about see the nucleus if you find somewhere very dark I believe the most distant object you can see with the naked eye what's key here is it's not called the great spiral galaxy Andromeda it's called the great nebula because at this time in the history of astronomy we didn't know what these objects were the idea that a spiral nebula could actually be external to our own galaxy wasn't a new idea right quite correctly surmised in 1750 our own Milky Way could be a flattened disk of stars Immanuel Kant five years later postulated this theory of Island universes that our Milky Way was one of many disjoint and separate collections of stars this leads us to a very very important question where is our place in the universe how do we map out the space around us and how do we fix ourselves in amongst all of these objects that we observe and the Andromeda galaxy was really key for making a very big change in our understanding of this so what the software is doing at the moment in the top left hand of the screen you can see the guide star now this is the star that the telescope's looking at in the sky remember everything in the sky is moving the equipment and we're using here has to track the motion of the sky very accurately so we hopefully won't see too much movement of that and whilst that's guiding the telescope the main imaging camera we'll be taking in this case a two-minute exposure the thing is the own droplet galaxies whilst it's the biggest and brightest galaxies in the sky it's still quite a tricky galaxy to image because as you can see from this image here the nucleus of the galaxy is so bright compared to the outer spiral arms so we still have to take lots of images to actually get a good end result in 1920 a very important event in scientific history took place called the great debate the Smithsonian Natural History Museum hosted this debate between Shaklee and Curtis the astronomers divided into two camps one of which says no these spiral nebulae are actually inside our own galaxy and they're just funny strange objects and the Milky Way as we see it is essentially the entirety of our observable universe whereas on the other camp you have the proponents of the island universe theory and it really sort of summarized the state of where we were as a community at that time it wasn't until 1925 that this issue was really put to rest by the very very famous observations i Edwin Hubble who used the Mount Wilson 100-inch telescope the largest telescope in the world at that time to measure Cepheid variables in m31 and these are a very very special class of stars that are known as standard candles so by measuring how they vary in a particular way you can figure out how bright they are and that lets you find out how far away they were and this conclusively proved that the distance to m31 was such that it is actually 2.5 million light years away outside our galaxy it's the other really big galaxies in the local group so the local group is this collection of a dozen or so galaxies of which the two largest members are the Milky Way and m31 the Andromeda galaxy there's a fairly long-running argument as to which is the biggest and which is slightly not quite so big you know it's like the Milky Way it's got a disk of stars it's got a bulge in the middle the Bulge is clearly not quite round in the case of the Andromeda galaxy and we think it's the same in the Milky Way there's a kind of a bar shaped bulge in the middle so as far as we can tell it really is very similar to the Milky Way a spiral galaxy inside my own Milky Way has a not only a collection of stars in it in a spiral shape but there's a lot of gas and dust in between the stars and the nice thing about the own dromeda galaxy is tilted over an intermedia angle and that does give us a chance to see the two dust lanes that sort of delineate the spiral arms effectively very very clearly let's do the job properly what we have to do is take at least a couple of hours worth of images but I think the sky will allow us to do that tonight but if we were able to do that with selective processing we can shrink the size of the nucleus of the galaxy and then we'll start to bring out the faint of dust lanes there's a lot of noise in the image as well because the skies so artificially bright by the moonlight you can see these sort of dust effects and things like that so it's not a pretty image but certainly we could go ahead and take them you know maybe another three hours worth like that and then we'd start to get a fairly strong image although on the brighter end of things is a beautiful regular normal-looking spiral galaxy if you take very deep exposures and really look at the faintest parts of this galaxy you find it's a complete mess that's all all sorts of things going on around it so there's a classic picture of the galaxy there's the galaxy itself in the middle and that's sort of the extent you would typically associate with the galaxy and then these black stuff out here is what happens if you look at photographic plates and just count the number of stars so you can actually get out to very very faint levels in these galaxies by doing these star count analyses so you can see there's a huge stream of stars piling into the galaxy from one side and it looks like that's a little satellite galaxy which started out here somewhere as it's falling in its got torn into these sort of long shred and is in the process of falling into the galaxy and then there's all these other messy bits as a dark patch over years as a extra bunch of stars here there's a bit that sticks out there is even the bit that sticks out on the other side entirely it's basically not a nice regular looking collection of stars and it really is because in these outer parts you're seeing the remnants of bits and pieces that are falling into the galaxies over time is this like when you see a really beautiful or really handsome person and then when you get up close to them you see their faces and although it really is yours' in all the wrinkles you really are seeing things which you only see when you look in very sharp focus very much up close and you know the camera up in a sharp focus close-up is never very flattering or you typically remark you typically don't it you open up the book you look at that picture and you think to my eye it's very obvious what that is because I've grown up knowing that this is a majestic galaxy you know a twin if not slightly larger than our own but it's very interesting to imagine looking at that and thinking oh well that just might be something just beyond the nearest stars to really understand the change in perspective that happened almost instantaneously when we place these objects in their rightful place in the universe is really quite extraordinary

Channel: DeepSkyVideos

Views: 308,457

Rating: 4.9024739 out of 5

Keywords: astronomers, messier, space, galaxies, nebula, nebulae, stars, universe, deepsky, deepskyvideos, deep sky, telescope, Messier, Messier Objects, Messier Catalog, Messier Catalogue

Id: N5fdsSRTJfg

Length: 8min 31sec (511 seconds)

Published: Thu Aug 30 2012