The Astronomy of Stonehenge - Simon Banton - Origins Conference

Our first speaker I've known for many years, he spoke at Megalithomania back in 2018 and he is one of the, in my opinion, I think many other people's been, he's one of the leading experts on the ancient site of Stonehenge. I'm sure you've heard of it and also really what's going on in the sky around Stonehenge, the archaeoastronomy of the site. He's appeared on Stargazing Live and The Sky at Night amongst other things. He worked at Stonehenge for six years and he's been researching the archaeoastronomy of this particular site for a very very long time and today we're going to get an overview plus new revelations about what has been discovered recently. So please give a warm welcome to Simon Banton. Well thank you very much and thank you for inviting me to speak here. We've got a lot to get through with this so I'm going to just crack on with it. This is the astronomy of Stonehenge, well some of it, because the topic's enormous and if you couldn't escape I'd keep you here for a few days. That's one of my first attempts at the astronomy of Stonehenge. Most people who have a go at it start with a map and draw lines all over it and you've got to pay more attention to the landscape and the shapes of the stones, not just the pure directionality that you get when you do an orthographic projection like that. So archaeoastronomy, that's what I am. I am an archaeoastronomer and as Ed Krupp from the Griffith Observatory once remarked, archaeoastronomy is a word with too many vowels and archaeoastronomers do not go around digging up old telescopes, that is not what we do. We're obsessed with humanity's relationship with the sky going all the way back. So why do we think Stonehenge has got any astronomy at all? It might seem really obvious to us but we've had pretty much the last 60 years since archaeoastronomy became a discipline, we've kind of got comfortable with the idea that Stonehenge is an astronomical observatory. But why exactly do we think that? Perhaps the best place to start is with this very familiar quote that you probably recognise, Diodorus Siculus, classical author, writing about the Gaulish Celts, the Hyperboreans and a magnificent spherical temple or temple of the spheres, better, somewhere in those islands where the moon comes very close to it and there's some kind of connection with the sky going on. Now arguably this is about Stonehenge, it might be the earliest reference to Stonehenge that we've got. Could be about Calanish or other stone circles further north but I think it's probably about Stonehenge and this is around 2,000 years ago, it's the earliest reference that we could point to and say perhaps. And then nothing, not a sausage for pretty much 17 centuries until the mid 1700s when Dr John Smith in 1771 says the apex of stone number one, the heel stone, the outlier for away from the stone circle is the thing that points directly to the place of Okay that's an interesting idea, it's completely wrong. He stole that idea off William Stookley who about 30 years earlier said it's the avenue, the ceremonial avenue that runs up to Stonehenge from the north-eastly direction, it's the centre line of that avenue that points to the summer solstice sunrise and that is correct and it's really quite an astonishing revelation and understanding by Stookley because when he comes to this realisation we're still working on the Julian calendar, we haven't switched to the Gregorian calendar by this point and although there was a fair on Stonehenge down going all the way back to the medieval times in the Julian calendar summer solstice wasn't June the 24th or the 21st, 24th was when the traditional fair was held, traditional midsummer's day, summer solstice was June the 10th so if you rocked up to the fair and looked out over the heel stone and down the avenue you would not see the sun rising in that direction, it would be off to the right somewhere because you're 14 days after the summer solstice so the fact that Stookley realised this when he couldn't just go and observe on the day of the really quite remarkable, well done William Stookley, not so well done John Smith for pinching the idea and getting it wrong. So brilliant, it's all about the summer solstice sunrise isn't it, every year 21st of June up to 40,000 people gather in that field overnight in the stones and they wait there to watch the sun rise over the heel stone and it doesn't, mostly because it's raining but on the rare occasions when it does rise over there it doesn't rise in the right place. Now I used to work at English Heritage and I got the job there because I have a background in physics and astronomy, I really wanted to abuse my staff privileges to get into the stones to take some observations that you can't normally do and so for a number of years I showed up in the week leading up to solstice and after solstice very early in the morning to get into the centre to try and catch the summer solstice sunrise over the heel stone in that direction without there being that many people in the way and if this works you should see what I recorded. Can you see the sun rising there? I am exactly on the axis, I'm exactly in the centre in the right spot, notice the heel stone is offset to the right of that gap between the stones there. That is what I was after, took me 14 years, brilliant, hooray, now I can sleep. Now okay let's look at a close-up of that, there's a still that was taken at the same time, you can see where the sun is, you can see the heel stone, that's the line of the true horizon and it doesn't rise today where it did when Stonehenge was built 2500 BC for a couple of reasons. The first reason is there's a whole load of trees on the horizon of Lark Hill that weren't there 4,500 years ago, it was a bare open plain you could see for miles but those have been planted in the last century and when the military were putting their first airfield up on Lark Hill down there the private owner of Stonehenge Sir Edmund Antrobus insisted that they left a gap between their aircraft sheds so that it wouldn't obscure the rays of the sun coming down on the solstice and the military were quite accommodating and they did and that's called the Lark Hill sun gap that they left between their aircraft sheds. Sadly the trees have grown up in the intervening period and so if you ever hear a news story about somebody going to jail for hammering copper nails into trees on Lark Hill down that would be me. I really want to restore that sightline but that level of trees offsets sunrise it causes it to delay its appearance and so you don't see it until it's got up a bit and it's off to the right that's the first reason it doesn't work and the second reason is the change in the earth's tilt. 4,500 years ago the earth was tilted at 24 degrees and now we're 23 and a half degrees that's called the change in the obliquity of the ecliptic it is not the precession of the equinoxes that's a different effect that's the spinning round of the earth's axis of rotation like that pointing to different parts of the sky not the nodding backwards and forwards of the axis from about 22 and a half degrees to 24 degrees over a 41,000 year cycle. The effect of that change is four and a half thousand years ago the sun rose about a than it does today it rose closer to the north-south line and it sets close to the north-south line when Stonehenge was built so that's where the sun would have risen when Stonehenge was constructed to the left of the tip of the heel stone not out of it not to the right of it to the left of it okay so that's why it doesn't work but you might say why are we bothering to stand in the middle and look outwards anyway what happens if you stand over there by the heel stone and look in the other direction what do you see then what you see then is this this photograph is about 10 minutes after sunrise on June the 24th a few years ago that's the shadow of the heel stone four and a half thousand years ago without the trees and with the earth's tilt different the tip of that shadow over there goes straight through this gap this is the deliberate entrance way into the stone circle the gap here is wider than all of the other gaps in all the other stones around the outside the builders left that as a deliberately wider entrance into the centre the tip of that shadow runs through there across the centre of the monument and lands exactly on the altar stone flat slab of micaceous sandstone lying down on the ground in front of what was the tallest trial Terry Meaden we all know Terry Meaden noticed this in the 90s and he's absolutely right these days we have to wait for the sun to rise quite a long way to get that nice strong shadow and that's why it's offset to the right because the sun's going in that direction four and a half thousand years ago that strong shadow straight through the middle Terry thinks that this is a sacred marriage he says the stonehenge represents the sacred feminine with the circular form and the horseshoe of triathlons in the middle the earth goddess if you like and the heel stone Mr Pointy is the sacred masculine and this is the height of the sun's power somersaults this he thinks that the shadow of the heel stone represents the symbolic fertilization of the earth goddess by the sky father at the height of his power and it worked quite nicely because nine months after the somersaults this of course is vernal acrinox so the key thing here is don't stand inside the monument looking outwards necessarily here's the summary heel stones the somersault is sunrise marker no it's offset to the east of the primary axis avenue aligns with the somersault this sunrise yes look through stonehenge not out from the middle there's the primary solstice axis to somersault this brilliant we all know that fabulous uh except we've changed our minds it's all about the winter solstice sunset these days that's an idea that started about 120 years ago and um okay it's because of the way the horizon is uh arranged at stonehenge it's almost exactly perfectly opposite summer solstice sunrise 180 degrees out and because english heritage has interpretation officers and they believe that 900 tons of rock in a field lined up is not obvious enough they put a great big bronze arrow in the middle of the old road one lane and labeled summer sunrise the other labeled winter sunset crack in so i'm standing where you'd watch that winter solstice sunset direction now obviously if the avenue is the defining line of this primary axis you should be able to go out into the landscape up towards lark hill stand there with a camera and watch the sun set plop into the center of the stones so i thought that was worth a go so i worked out where to go stood there and did this plop that works really nicely bit of a close-up there we go exactly on the there's the winter solstice sun beautiful hey great stuff that's not quite right that last gleam there should be there between the uprights of the tallest triathlon and it's not because the tilt the earth has changed so you've got to factor in this change in obliquity of the site so there's the summary of that bit the avenues the winter solstice sunset yes last gleam falls between the uprights of the tallest triathlon yes but only four and a half thousand years ago when obliquity was 24 so there is the thing that everybody knows about stonehenge that is the line that's what everybody accepts is true fabulous that's the sun dealt with forget about the sun what about the moon remember that quote from theodorus moon appears very near the earth and the god visits the island every 19 years or so 19 is a very lunar number so uh yeah okay in the 1960s a chap called peter newham and another chap called gerald hawkins who you might have heard of independently came up with the idea that there were lunar alignments at stonehenge that were focused around the station stone rectangle and these are four small sarsen stones only two remaining one there and one there the sites of the missing stones are marked by what's called the south barrow down here and the north barrow over there they're not burial mounds but they're just enclosures a right raised bit of ground there they both suggested the long sides of this station stone rectangle are tied in with the extremest possible moonrises and sets interesting idea and so in 2006 the last time we had major standstill and we're coming up to it again 2024-25 last time 2006 i took friends stood them in the north barrow over there and said look over that station stone in 10 minutes the full moon will rise over it they went bollocks and then they went oh every 18.61 years the moon at its extreme rises over this chap he wouldn't get out of the way there's the path of the moon there's the station stone there's the this works so peter and gerald came up with this idea it's a great idea we get to check it now again because we're the next standstill and back in may there was a major present moon set at its northernmost extreme and i happened to blag my way into stonehenge with a research team from Bournemouth university to take some pictures of this because they're trying to confirm it and it happened to be the night of the aurora storm so ha there's the crescent moon bottom left a bit of a close-up there's the station stone illuminated by my torch that's the track of the setting moon factor in obliquity and that goes that way by a degree it's off to the right by a degree four and a half thousand years ago or more that sets into the base of that station stone along the long side of the station step rectangle so it works there's a lunar aspect to the monument that's tied in with that station stone rectangle and peter came up with a new idea a second idea about some of the aspects of the lunar parts of stonehenge here's his plan station stone rectangle one two three four there center of the aubrey hole circle which is there over in the northeast causeway there's a set of post holes which he suggested might have been a set of ranging rods to try and track this lunar northernmost moon rise and just to the left of the heel stone there's a set of four post holes unfortunately known as the a-holes we're stuck with that name he suggested the heel stone here marks the mid swing of the moon at its northernmost extreme major sunrise major moon rise to minor standstill and the thieves over here are key there's a different plan station stone rectangle with the diagonals across it to mark the center up there in that blue circle is the northeast causeway what's going on there there's the heel stone there's the a-holes peter and aubrey bowl later suggested these actors a countdown year by year the winter full moon which rises in this direction to the major standstill so five years before four years before three years two years one year and then the major standstill is that it's quite tricky getting the moon exactly at the major standstill at rising because it moves through the sky really quickly but that is pretty damn close it's a very interesting idea so the earthwork looks like it's lunar with the station stone rectangle and the big stones are solar there's that summary but we've left out a whole solstice axis we've done summer sunrise to winter sunset what about winter sunrise to summer sunset the notch if you stand on the visitor path at stonehenge on the western side of it tarmac path when you look through these two stones of the circle that are standing you see the uprights of the western triathlon there and there is a little notch worked into the edge of that stone stone 58 and if you sight through that notch you see that the edge of it the open side is closed up by the edge of one of the triathlon uprights on the far side of the circle step 53 that forms a really nicely constrained sight line to conybury hill to the southeast and remember that little pile on which is not neolithic but it's a very useful marker nonetheless everyone needs a foresight there's the alignment visitor path is down here in the bottom through that set of three part of the circle through the notch in this stone past the edge of that stone past fallen stone eight which doesn't get in the way when it's standing off to the winter solstice sunrise position and in 2012 we had a perfectly clear winter solstice and i'm standing on that line at the top end of that arrow and i took that picture there's the full orb sunrise winter if you factor in the change in the bleak to the ecliptic it moves to the right by one degree to there okay forget the numbers that's me being obsessive you drop that on the notch alignment and you get that it's targeted like a rifle sight really really accurate a very tightly constrained sight line that's first noticed by gordon freeman in 2008 in canada stonehenge did a lot of work with an alberta in canada medicine wheel and then drew analogies with stonehenge came and visited the site did actual observations on the ground paid attention to the shapes of the stones and critically the horizon altitude didn't just draw lines on a map well done gordon spotted something new that's the view just after winter solstice at the sunrise through that notch in our fabulous and of course i always make a point of turning my back on the sun looking the opposite direction just in case there's something to see now in this case there is something to see these black blobs here are the shadows of the stones and that yellow path is the beam of sunlight shining through that notch running out along this landscape which by pure coincidence after 262 miles goes straight down the passage at newgrange and i mean exactly i don't mean just about this has got to be a coincidence newgrange is 3100 bc these bits of stones are 2500 bc 262 miles the irish sea in the way long distance surveying and alignment laying out over that sort of thing the science half of my brain goes nah but the respect for the ancients half of my brain goes draw your own conclusions it's a lovely coincidence okay so the opposite direction for the winter solstice sunrise there's that line which runs exactly along the midline of a very specific and important stone opposite direction to summer sunset so now we're not looking that way we're looking this way back along the same alignment this should point to the summer sunset when stonehenge was built if we're lucky and if you stand there and look in that direction that's what you see slightly off the alignment here because you've got the collapsed lintel and upright of the tallest trilithons partner stone in the way there's the notch so you've got to be a little bit off it just to make it out and in summer solstice the sun should set into that notch if you're standing in the right place does it of course it does there's the sun it really was that colour as well that's not a photoshop the military had set fire to Salisbury Plain training area again as they do it with fire stuff at it so the sky was really full of dust and smoke nice pink sun setting into that notch four and a half thousand years ago that's perfect brilliant so there's the sunset line summer solstice sunset again looking along the midline of that very specific and important stone so that's the secondary axis and that and the primary axis intersect at 80 degrees 80 and a bit degrees 80 in round numbers at a very specific spot exactly over the centre of the altar stone there's the altar stone lying down there that stone there that's the stone the tip of the shadow touches those two axes intersect exactly over the centre of it altar stone's not perpendicular to that main axis it's at 80 degrees to it that's why the secondary alignment works along its long axis very cleverly positioned I think it suggests that the altar stone has always been prone not that it was once upright in that position and there was knocked over when the tallest trial of normans bits collapsed so okay 80 degrees that's interesting anything in the stone age landscape with 80 degrees associated with it apart from this well yeah there's the fabulous treasure of bush barrow normans and down barrow cemetery it's bronze age around about 1800 bc so you know a good few centuries after stonehenge has been completed and it's beaten gold that's about a millimetre thick and it's about oh I know 25 centimetres that way about 15 centimetres that way very very thin beaten gold and its axis is 80 degrees that lozenge encompasses the geometry of the sky at the latitude of stonehenge very neatly we do not understand what the engravings on the front represent but I think it's conveying information because they haven't got an alphabet and written language we tend to assume they weren't able to communicate knowledge that's not necessarily the case we should be looking for the ideas and the information in the symbology of the artwork and the geometry of these things so that's the bush barrel lozenge wonderful dug up in 1808 by richard colt whore and william cunnington looking for blink in the grave of a chap that's ended up being called the stonehenge heavily overloaded word but this is an emblem of knowledge these people understand this afterwards you can take that you can drop it smack in the middle of stonehenge there's the geometry of the site fantastic that's the sun and the moon if you've got a handle on the way they move and you understand this periodic cycle the regression of the lunar nodes the 18.61 years from major lunar standstill backwards and forwards to the other one then you've got the potential to work out when an eclipse is going to happen mid 60s two people that's the 2015 near total solar eclipse over stonehenge world's press stood there in the wrong place press photography released after this showed a beautiful near total eclipse about that altitude so their press photography was a photoshop that's what it really looked like two people in the 60s came up with the idea of predicting eclipses using stonehenge gerald hawkins again and later fred hoyle refining it actually given the task of trying to tear this idea down and came up with supporting it and a slightly simpler way of moving markers around the aubrey hole circle to track the sun and the moon the aubrey hole circle is 56 evenly spaced pits just inside the bank of stonehenge very early 5 000 years ago and so gerald and fred came up with a recipe fred's is the one i'll show you it's a bit simpler you've got to imagine stonehenge represents the earth and the ring of aubrey holes represents the sky divided up into 56 spaces and all you need are four markers you need a marker for the moon which you move two holes a day so it goes around 56 holes in 28 days pretty close to 27 days which is the time it takes the moon to go around the earth my apologies not exact but close and you move the sun two holes every 13 days in the same direction that goes around once in 364 days pretty close to 365.2422 not exact and you need markers for the crossing points of their path in the sky they're called the nodes the ascending and descending nodes and they move around the circle in the other direction three holes a year which means they go around once every 18.66 years which is extremely close to 18.61 which is actually how long it takes the nodes to process around the sky you can cope with the inaccuracies it turns out the nodes are interesting that's why there are crossing points because the moon's path is angled to the apparent path of the sun so twice a month once it goes through that one and once it goes through that one and you get an eclipse when the sun and the moon are both at the crossing point and either in the same direction solar eclipse or opposite each other lunar eclipse but you can also have eclipses when they're very close to the nodes that turns out to be one aubrey hole either side so let's work this there's the march 20th 2015 solar eclipse the sun the moon markers are both in the same hole next to a crossing point a node marker in this zone of possible eclipse there's the zone of possible eclipse on the opposite side okay so that's saying there's an eclipse of the sun on march the 20th people showed up to see it these two chaps lovely tinfoil helmets very nice model of the solar system i think they were dutch let's work this march 21st moon markers move two holes so it's going to go around once in 28 days 22nd 23rd 24th 25th 26th oh hang on got to move the sun marker two holes every 13 days so i'll we'll do it one hole after seven days and the next hole by another six days and you know that that's fine we'll be able to do that it's quite complicated to keep track of you can find yourself at sixes and sevens okay keep going 28 moons move two holes again 29 30 31st 1st 2nd time to move the sun again so it's now moved two holes in those 13 days keep going april 3rd april 4th right full moon moon marker is exactly opposite the sun marker with the earth in the middle that's a full moon they're both within the zone of possible eclipse this is saying that there ought to be a lunar eclipse on april the 4th 2015 which is clearly nonsense except it isn't this does work but you've got to cope with the inaccuracies and that can get very complicated you can at least sort the sun out twice a year if it's not exactly in line with the axis and all the whole either side of that main axis you can fix it at summer solstice or winter solstice if the moon marker is not exactly opposite the sun marker at full moon you can fix it and if you keep track of the inaccuracies and correct for them periodically like that you can be accurate to the day for potential eclipses and the key thing here is lunar eclipses are more obvious and important than solar eclipses you've got to be a very specific spot on the earth with very specific conditions to be able to see a total solar eclipse they don't happen frequently from the same spot if there's a lunar eclipse happening tonight and you're on the hemisphere of the earth that's looking out to the moon when it's going into eclipse you will see it and four and a half five thousand years ago if you're wandering across the landscape during the full moon because it's great you can do a bit longer travel because there's going to be a nice bright light in the sky you're going to notice it suddenly go out or go blood red you're going to pay attention to that the moon eclipse is much more striking and obvious than a solar eclipse from any particular spot on the earth so this is the idea the Orbitals can be an eclipse calculator and Hawkins publishes it in Nature initially and this chap Richard Atkinson said it's rubbish these people are howling barbarians dear boy there's no way these people were capable of doing this sort of astronomy four and a half thousand years ago rubbish howling barbarians Richard Atkinson luminary of Stonehenge archaeology from the 1940s 1950s did the worst excavation ever done at Stonehenge never documented terrible never properly published books the type he wrote a paper in antiquity I think it was saying it's called Moonshine on Stonehenge right go Hawkins right go at it in 56 there's a significant number for eclipses in the ancient world we'd find evidence of it elsewhere the implication being that we don't but it turns out we do this is Plutarch 2nd century AD writing that the Pythagoreans believed Typhon their demonic power their 56 sided polygon belongs to Typhon some who give the name Typhon the shadow of the earth in which they believe the moon falls and suffers eclipse 56 eclipses 1800 years ago classical literature we have known about using 56 to keep track of the sun the moon and the crossing points for a very long time it turns out it's just that archaeologists and astronomers don't tend to read Plutarch very much they really ought to so there's the lunar eclipse of September 2015 very nice and that is Typhon this is what we're talking about that's the shadow of the earth that's how big it is in the sky compared to the moon and there's Typhon the Typhonian beast that's what we're talking about that's what Plutarch and Eudoxus and the Pythagoreans are referring to okay but is that the only 56-ness that we find around the place associated with these sorts of monuments well no it isn't because in Sweden we've got a stone boat called Allestanna and it's got 56 stones plus three for Proumaston still and it looks beautifully out over the water to the winter solstice sunrise it's aligned long axis that direction it happens to be placed at exactly the right latitude where remember at Stonehenge summer solstice winter solstice are 80 degrees apart Allestanna it's exactly a right angle it's been positioned very carefully so there is 56-ness elsewhere associated with tracking the sun and the moon potentially and eclipses can't say for definite that's what they used it for but it's possible are these people howling barbarians as Atkinson said of course they're not he's failing to take into account that humans have been looking at the sky for tens of thousands of years the oldest evidence we've got of lunar phase markings is around about 35,000 years old from a carved bone from central Europe it's what we want to do we want to stare at the sky and work out what's going on because of all of the things in our environment it's the only intangible one that mountain looks interesting i can walk over there climb it and touch it that island looks interesting i can walk to the beach invent a boat build a boat get in a boat paddle a boat cross the island touch it no matter where you go and how high up you go you can't touch the sky bringing the sky down to the ground marking the movements of the key luminaries the sun and the moon and keeping track of where they're going to behave oddly that almost puts us on a level with the gods we're understanding what they're doing we can predict what they can do this is a very human thing to do before we're mechanized humans with boundaries and records everything in the landscape is sacred that tree that rock that bend in the river all of it is special and sacred it's a song line landscape we've forgotten the words thank you one more thing i blame that altar stone is a blue stone and for a hundred years since we finally nailed down that the blue stones probably came from southwest wales the altar stone which is clearly not a sarsen or not a local stone to stone edge has been classified as a type of blue stone originally thought to have been picked up in milford haven off the senai beds probably en route from preseli to stonehenge need a big rock all right stick it on the boat off we go then about eight years ago provenancing changed and it was no longer the senai beds milford haven way it was brecon beacons that's where the closest match was the old red sandstone interesting changed the perception of how the blue stones came from from preseli to stonehenge from being a water-based route to being a land-based route probably along the line of the a40 through wales and then crossing the seven then coming down that direction interesting changed our perception of where the traveling might have been done from and how they got to stonehenge and then about 18 months ago rob ixer and a couple of other people were analyzing the blue stone fragments that were dug out of the monument and curated in museums in the 19th century secure contacts we know they were broken off the bottom of the altar stone and realized that it doesn't match brecon beacons either it's composed of fragments in there that come from the underlying basement rock that is so old it has to be north of the iapetus suture these are the oldest rocks in britain it has to come from the orcadian basin north east scotland now of course the media got hold of this and went oh we don't know what the orcadian basin is can we say orkney no we're going to say orkney so everyone said all the media and then two days later another paper came out saying it doesn't match any of them and the media never came from orkney come from the orcadian basin somewhere up here okay there's lots of cool stuff going on in orkney nassau particularly alderstone circles in britain up there there's lots of cool stuff going up here there are recumbent stones focus on the moon lots of stuff going on over here carnish this is society up there that's paying close attention to the sky that's where the altar stone actually comes from really interesting we know where it is now 600 miles south and it's lying there under that red line that's where it is now was it always there there's the intersection of the axes the perfect spot very nicely laid out exactly the right angle to capture all of that but in the 1950s richard atkinson was doing some digs in the monument reopening trenches from hawley from the 1920s started digging around this sort of area seeing it would bottom out some of all these digs because he never got right down to the bedrock stopped and in the bottom of a hole here you found a stone hole sunk down into the chalk containing a fragment of a group one stone axe probably cornish a stone used to stand there and it doesn't stand there now somebody took it out and somebody put that there to say sorry to the ancestors it is possible that the altar stone once stood upright in that stone hole and was removed by the people who built the big stone phase of stonehenge and relocated to there it's exactly on the primary axis and i thought that's really interesting i was chasing this down because andy collins is interested in a possible second altar stone so i was going back through archaeological records looking at big illustrations and plans of all of the excavations in the 20th century and came across that and thought that's really interesting what i did next made me go oh my god no really that's the station stone that's where the altar stone was this line is parallel to that line this line is winter solstice sunrise over there summer solstice sunset over there if the altar stone stood there originally then we've got the secondary axis caught through there so if we plot that on a plan we can look at what we've actually got with only five stones you can catch the entire sky you've just got to put them in the right place at the right latitude station stone station stone station stone station stone altar stone there short sides of the station stone rectangle summer solstice sunrise winter sunset they're parallel to the primary axis the altar stone is on that primary axis halfway from there halfway from there long sides of that rectangle northernmost moon set top left southernmost moon rise bottom right you put the altar stone there in that stone hole wa3639 that lines up with the station stone to give you summer solstice sunset and that through there to there gives you that winter solstice sunrise line which is echoed later along the long axis of the altar stone when it's repositioned that is all you need at this latitude to catch all of the sky except hang on we've forgotten something there's something missing from that diagram where's the northernmost moon that can ever happen and the southernmost moon set if you put that stone in that hole and instead of having it perpendicular to this line you twist it slightly so that it's 80 degrees so this line runs along its face perpendicular to that is the northernmost major moon rise southernmost major moon set that is the entire sky captured in five stones that's brilliant that is elegant that is a significant monument you look at that simply that's all you need that is literally all you need station stones and an altar stone at 80 degrees the primary axis gives you everything four sarsen stones one scottish stone they give you those lines that addition gives you all the rest of it i think that the people in orkney understood the sky to such an extent that they realized they were in the wrong place to catch it all in a nice simple geometry and i think that is the motivation for traveling south from orkney bringing an altar stone from somewhere in that region which is the echo of their society that's the founding stone if you like take it to the right place 51 10 north in our language set it up there and you've got the entire sky probably before 3000 bc then the people who come along two and a half thousand bc with their idea of what we need here is bigger rocks they leave the station stones alone but the altar stone's and they put it there on this same 80 degree axis and they've retained all of those alignments but they've embellished it that's the minimum stone edge that you need to catch everything heel stone slaught the stone stone 16 gives you the sight line through the primary axis 57 58 stone 80 the altar stone and 53 over here give you that tightly constrained sight line to the secondary axis you've still got the station stone rectangle giving you the moon and you twist that so it's 80 degrees so it lies underneath that axis and then perpendicular to it is your that still wasn't enough for them because they put one extra stone in the stone circle to echo that upright altar stone and it's that stone there that is stone 11 it's half the height and half the width of all of the other uprights in the outer circle and it is positioned precisely so that the line from that station stone through the spot where the altar stone used to stand upright goes through 11 to preserve that particular site that's what it was that's what it is there's potentially some very interesting geometry going on down here with these divisions across there but i've not gone into that yet that's the most elegant capturing of everything that goes on in the sky that i've ever come across i've been studying this stuff for 35 years i discovered that in august this year and it's all because andy collins went uh what about the second oldest then thanks andy you sent me off down a rabbit hole that's come up with something really fascinating richard colt hall 19th century financier of william cunnington's excavations and barrows published all those findings in a book called ancient vulture and the preface to it basically says about stonehenge how grand how wonderful how incomprehensible about now thanks guys