Well good evening everyone, and welcome to the 2021 virtual Grand Canyon Star Party!
I'm Ranger Rader Lane, the national park service coordinator for the event,
and for 31 years running Grand canyon has been celebrating our pristine night skies
through the annual Grand Canyon Star Party.
Now ordinarily we have hundreds of astronomers and thousands upon thousands of visitors
to come to the park to enjoy eight nights of some of the darkest night skies in the United States.
Now each evening is kicked off with a special guest speaker in our theater
followed by telescope viewing, constellation tours,
night sky photography workshops, and much much more.
Next year's Grand Canyon Star Party is June 18th through the 25th 2022,
so mark your calendars and cross your fingers that we'll be able to celebrate on site next year.
This year we are bringing Star Party yet again to the
virtual realm, and we're really excited!
We have a whole host of incredible speakers who have been willing to participate,
and before we introduce our special guest speaker this evening
I have a few entities that I would like to thank from the National Park Service
for their help in supporting this event.
First I'd like to thank the Grand Canyon Conservancy.
Now, they're the park's official non-profit partner,
and have done incredible work promoting dark skies in Grand Canyon and beyond.
The International Dark Sky Association; they're the entity that
certified Grand Canyon National Park as an
International Dark Sky Park back in June of 2019 and
we are very grateful for that and for all the work they do.
I'd like to thank the Tucson Amateur Astronomy Association.
They are the group that has been coming up for decades
to the Grand canyon Star Party to volunteer their time,
and share the wonders of the universe
through their telescopes and equipment, and so we, we just
really cannot do this without the TAAA so thank you to them.
And then finally we'd like to thank the Society for
Cultural Astronomy of the American Southwest.
They are an entity that has helped us coordinate many of
the speakers this year so we we thank them for their help.
And with that I would like to introduce tonight's special guest speaker.
Tonight we are honored and excited to have with us David Koerner.
David is, he got his PhD in planetary science at CalTech.
He worked at the jet propulsion laboratory on the formation of solar systems.
His emphasis is in observational astronomy,
having worked on, worked with telescopes such as the Hubble Space Telescope, the Very Large
Array, the Keck Telescope in Hawaii, and many others.
He focuses on disks around newborn stars from which planets are formed and
just does all sorts of incredible stuff in the field of astronomy. He was a faculty member at
the University of Pennsylvania before coming to northern Arizona University.
His teaching focus has been in astrobiology,
but he was instrumental in adapting an Intro to Indigenous Astronomy course
to the Northern Arizona University campus which became wildly successful,
and was based off of a course created by Nancy Maryboy and David Begay,
two speakers we hope to have later on this week,
and they created an online forum of that program years prior.
Now retired, David is a resident of Northern Arizona
and enjoys studying the various cultural astronomical sites
of the greater Grand Canyon region,
so, David, thank you so much for joining us tonight
we're, we're so excited and thrilled to have you!
Thank you Rader!
Well hello everyone, I'm going to talk to you
about some of the wonderful sites in the grand canyon region
that you could visit when you come to the Grand Canyon!
I know many of you come to this area, attracted to its dark skies.
attracted to its dark skies, and many of these places have dark sky official status.
Whether they do or not, the skies are dark and beautiful. But they also have many traditions
of cultural awareness of the sky from ancient people, and so I'm going to talk
a little bit about places you can go nearby, where studies have been done, and we have recognized
interactions with the night sky from ancient astronomers.
Hopefully this can add benefit to your trips to the region.
Now I'm going to discuss sites that have been
acknowledged and discovered through a field called archaeoastronomy.
That name sounds kind of like its two components - it's coming from archaeology and astronomy,
and archaeoastronomy is the study of these archaeological sites, and artifacts, and ruins,
to try to determine the astronomical practices, lore,
mythologies, and religions, and the world views of ancient cultures.
So in this talk series you've heard from present-day
native speakers about current astronomy in tribal lore,
and that falls under a field called ethno-astronomy, and it's very complementary;
we can sometimes use that information to interpret
prehistoric artifacts and their relevance to astronomy,
but in my talk I'm going to talk about a study of some of these sites.
Now an awful lot of the archaeoastronomy that's done in sites
concerns the alignments of ruins with celestial positions,
and so here's an example from Chaco of Pueblo Bonito.
The earliest version was facing slightly east of due south, but when added on to,
it had just a straight east-west line at the bottom to it, and of course this is
an alignment with the cardinal directions, but they in turn are very reflective of the sun angle,
and so you would get the most sun by facing due south over the course of a whole day.
We see many alignments, and this is one of the simplest alignments you can have.
But there are other celestial body positions that may align with ancient sites.
Now, we have to stop here for a moment just to help ourselves understand alignments,
with a little primer in a coordinate system called the horizontal coordinate system.
It's basically how you can point to things in the sky from your point of view,
just maybe standing in the open parking lot of the visitor center at a typical Star Party event.
There are two coordinates I want you to understand:
one is how high something is above the horizon, and that
would be a coordinate sometimes referred to as altitude,
and it's given in an angle where 90 degrees would be
directly overhead and zero degrees would be on the horizon.
And then the other one is a little more tricky; it's which
direction you're looking, and we use a coordinate called azimuth,
and azimuth is sometimes referred to as degrees east of north.
If you face due north you're at zero degrees azimuth.
As you start to rotate, looking toward the east you increase your angle.
If you went a full revolution around and came back to north you would have gone 360 degrees.
Here's a little up close: the altitude or elevation is measured from the horizon.
Those are two words we use for the same coordinate, altitude or elevation.
By the way, the zenith angle is the complementary angle measured from directly overhead,
and then here's the chart I want you to see because we'll use it for
our understanding alignments.
As you can see, zero to 360 degrees is full circle. If you look north is zero;
due east, 90 degrees; do south, 180 degrees;
do west, 270 degrees, and that's azimuth.
It's a useful thing to understand the alignments of buildings with the celestial events.
Now what's an example of a celestial event?
Maybe the most common one is the day, sometimes we call it the diurnal cycle,
where the sun rises in the east and sets in the west.
However as you'll notice, it doesn't always rise due east.
It sometimes rises a little north of east, sometimes a little south of east,
and that changes with the seasons, which brings us to another cycle, the annual cycle,
which is very important to native peoples and to ancient astronomers. Here you can see the sun's path,
you can notice, as you probably already know,
that in the summer the sun, it gets to its highest point
and we get a lot more sunlight. In the winter it doesn't rise quite so high.
But the other thing you should notice is where
the sun starts out and where it ends on the horizon.
If you look at say, the mid-summer solar path there, you can see that it rises
not directly in the east but north of the east, and also sets north of east.
Whereas in the mid-winter, winter solstice to be more precise,
the sun is rising somewhat south of east, and setting due south of east.
This position on the horizon, where the sun comes up and sets, is a very useful way
of knowing the time of year. Now you and I are going "why don't you just look at the calendar?",
because we have our western calendar, and we have dates and we just pin everything on them.
Well, you know our western calendar is not all that. I mean, if you have you ever noticed that
the dates of summer solstice and winter solstice are not the same from year to year, why is that?
Because the number of times the Earth revolves on its axis is not necessarily coupled to the time
it takes to go around the sun once. And so to be really precise of where you are in the year
you want to just watch and see when the sun hits these positions, and that tells you when you've
come full cycle. Now here's other examples of cycles.
A cycle is basically a periodic phenomenon. Things that recur in a time period,
and ancient astronomy is often focused on these cycles.
We've talked about two, the diurnal cycle and the solar year.
Another set of important cycles are the lunar cycles: how long it takes the moon to
go from one phase and back again to the same phase,
and also planetary cycles; when you see planets
like Venus return to the same place relative to the sun in the sky.
And ancient astronomers looked at all of these. My background here may look a little funny;
this is a Mayan calendar, and Mayans were masters of
measuring astronomical cycles, and planetary cycles, and lunar cycles.
You can see here examples of cycles in ancient astronomies.
The upper left is an example of using something called a gnomon, which is basically a kind of sun dial.
By looking at how the shadows move their orientation,
and lengthen and shorten during the day, you can tell time fundamentally.
Other cycles on here, right in the middle you see an astonishing thing, which is interpreted as
a full set of a lunar cycle from an Orig Nation Period. This thing is dated to
be 32 000 years old. So, ancient astronomy is really ancient!
If you look at the upper right, it looks like the ruin of an observatory.
I feel like I'm at Palomar when I look at this thing.
This is a Mayan observatory without a telescope, but it is oriented and aligned so beautifully
to see a number of things, including the cycles of Venus.
If you look in the lower left, this is Mayan writing
describing the cycles of Venus, and if you look in the lower right, and we'll come back to it,
you can see basically a notched kind of ruler that
measures where the sun-horizon rise and set positions are, and tells you to the month,
basically, what time of the year it is, and we'll come back and talk about that,
that's from Peru. Now of course when I used to teach intro to astronomy, we had an
outer space view of all these cycles, which is not what you necessarily see from the ground.
Notice how you're not on the earth in any of these pictures, and they show you cycles of planets, the
seasons, the solar day, and the lunar cycle, yeah there's a lot of detail here don't worry about it.
My only point is that when we teach intro astronomy we often teach
an off-the-earth perspective, whereas both in native astronomers, and in sky
watching, and in ancient astronomies, you are looking at celestial objects from the earth,
and so you look at their cycles as they appear from Earth.
So, one of the things we used to teach is putting these two things together to understand the cycles,
both from the ancient astronomy perspective and from the intra-astronomy perspective.
All right, so let's, start in with an easy kind of thing, horizons,
sunrise, and sunset watching - and this is a modern practice,
but was undoubtedly an ancient practice. What are we looking at here?
Those of you who are local may recognize in the horizon that this is
a horizon of the San Francisco Peaks, and I live just to the north of those peaks, but it's as
seen from the Hopi Reservation, in particular from the roof of a Bear Clan sun watcher's house.
And a paper done by an archaeoastronomer registered
where the sun sets as a function of day over these horizons,
and this is how the Hopi sun watcher tells what time it is.
The farthest sun set, in this case, to the left, is at the time of winter solstice.
And it is the sun watcher's job to pinpoint precisely when that happens,
and to do it a few days in advance. Now why? Because, when that happens,
you've got to start some ceremonies! They see the sun as moving to this position,
his winter house basically, and he sits there and it's cold! And it's going to keep being cold,
and if you want to go into the planting season you need him to hurry, turn around, and come back,
and make things warm again! So, a ceremony is a way of agreeing and placating the sun,
and saying "please come back so that we can
plant beans, because right now it's too cold. Don't stay there!"
And so, the sun watcher has to pinpoint when that's going to happen.
He has to say in a few days in advance so people can get ready,
and so he has to know very precisely, from a particular position,
where the sun set and sunrise positions are on the horizon, and that's how he tells.
Now this is just a natural alignment, but of course it depends on where you are looking from, right?
If he went to, you know, 10 miles south, it would not appear the same place on the horizon.
So there is an alignment, but it's the alignment of the position of viewing.
I can't help it, this always reminds me of Ansel Adams' photography remark where he
says "The key to great art photography is knowing where to stand" and of course
he was basically just saying, you know, framing the picture
is a big part of it, but the same is true for puebloan sun watchers. They have to know where
to stand if they're going to use horizon markers. All right, well, this was Chankillo in Peru,
you can add some some building elements. What you see here is just, this thing is 2300 years old,
or very - I'm sorry, I'm not sure if I've misremembered that but it's very old.
And you see the sun, and at different times of the year it will fall in those notches,
but only a scene from a particular position. On the right you see the observatory building
that locates where you are to look from. So, it's an example of an archaeoastronomical alignment
on solar horizon positions. Now let's talk a little bit about northern Arizona.
If you look on the right you see an azimuth diagram, and you can see marks
that show you where the sun comes up and where the sun sets at summer solstice,
and where it does that at winter solstice, and of course at equinox it comes up due east
and due west. Now this particular diagram is for a latitude a little bit north of us,
but I think this is a fun thing to know. I've lived in a meadow surrounded by
cinder cones for almost 20 years and I'm off the grid, so natural light is
very apparent. I can tell you a little notch in the trees exactly where the sun will come up in
winter solstice because I've just watched it year after year, and it's just a thing that you notice.
I think that's what ancient astronomers did as well. And so if you're in northern Arizona,
you can do this too. You can do this actually anywhere in northern latitudes, it's just your
angles will be slightly different. Just for the record, I think this is really easy to remember,
that at the latitude that we are here near Grand Canyon, the sunrise on summer solstice is
about 60 degrees east of north, and sunset is 60 degrees west of north.
I love knowing this because I like to know where the sun's going to come up or set at Grand Canyon.
So, I take a map of Grand Canyon and I can draw a line with these angles between
any two points on the rim where I want to do my watching from,
maybe Shoshone Point, and then I can tell by drawing that line exactly where the sun
is going to come up or set on a particular rim of the canyon. So it's, it's a fun thing,
and it's related to these archaeoastronomy building alignments.
Now I'm going to start with a site that's a little bit out of our local region,
just because it's such a beautiful comparison to what we were just talking about.
This is in Wyoming so it's a little farther out, but it's a great example of what are called medicine wheels.
And medicine wheels, there are quite a lot of them, especially going up into Canada,
and they are from the Plains Indians. If you ever want to go visit Bighorn Medicine Wheel, it's a good
it's a good stop on your way to Yellowstone. It's up in the Bighorn Mountains, it's pretty high
elevation so it's not a good winter visit where it will be covered with snow,
and you can see it looks almost like our azimuth diagram doesn't it?
There's a lot of spokes, so what were they looking at? Well there are also these cairns on the outside,
and if you connect two of the cairns, you often get a very interesting direction.
So, here's this, if you connect this cairn with the central one, whoops, sorry about that.
If you connect this cairn with the central one you'll get a line pointing to summer solstice sunrise.
Similarly, if you connect this one, you get summer solstice sunset.
So, there are alignments here, and Native Americans could go and determine the time of year.
Now you may say "why is there not a winter solstice?" and the answer is quite simple.
This is a high site, covered with many feet of snow in the winter, so it wouldn't be of very much use.
Now, what about some of these other lines that are indicated here?
You'll see if you know their names, you'll recognize the names of stars between several of the cairn intersections,
and that's probably right because these are among the brightest stars in the sky.
When those stars first are seen to rise out of the glare of the pre-dawn, is determined by,
also, a time of year. So they can be seasonal markings. However,
if you're gonna look every morning before dawn to see when you can finally see
some star in the glare of the sun, those of you who've maybe
tried at a Star Party to be the first to see, say, Jupiter, as the night gets dark,
you know that's very helpful to know exactly where to look.
If you're trying to look for Jupiter and everybody goes "oh I see it!"
and you're like "where? I don't see it" and you have a hard time seeing it.
So, it's a great advantage to have a marker here to say "look this star is going to rise
right at this position on the horizon, if you look from this cairn to this other one."
These are so-called heliacal risings. Of course, the stars always rise at that position unlike the sun,
at least within your lifetime, and as far as the accuracy with which you can see,
so, you can always look in that direction. And, I love, I confess I love the heliacal rising of
Sirius, known as the dog star, for which the dog days of summer are named, primarily, probably
because of the heliacal rising of Sirius happens in the second half of summer; that's when you can
first start seeing it, and it's a wonderful season event. My bathroom window looks right out on the
horizon and I know the notch in the trees where Sirius will come up, and I start looking for it in
early August; I'm like "No, can't see it," and then finally there it is, I'm like "Wow,
new season is upon us." So, it's a great thing.
All right, now these alignments have an interesting aspect to them.
You might ask, "Well how do you know that, that was a real alignment intended?"
And the answer is: sometimes we don't. I think nothing could illustrate this more than
this funny event that happens, which has been called Manhattanhenge.
The streets in Manhattan are aligned along the long axis of the island.
But that so happens to be 90 degrees off from the solstice rise and set points.
So the narrow streets aligned with these buildings have a funny phenomenon where
they're just a little bit off. So it's a few days before and after a solstice, the sun will rise and shine
at its rising point directly down the street. And this is a solstice kind of rising, and a lot of
people now get together and celebrate it, but the streets were not laid out for that reason.
I just want to point that out. And, so, if you're a little skeptical sometimes, that's not a bad
attitude to have, and archaeoastronomers have to always contend with some uncertainty.
All right, let's start our tour. I thought I would start with this amazing place,
and I understand my my colleague Brian Bates has talked about this a little bit in his talk as well,
Chaco Culture National Historic Park, again a tremendously dark sight
in the northwest corner of New Mexico, shown here in the map. The yellow lines there are ancient
roads which were laid out fairly precisely for those times, and Chaco was an amazing
metropolitan center. You can see on the right the remains of one of the ruins there.
I think that's Pueblo Bonito, it's kind of the MGM Grand of the ancient four corners world;
a giant many, many room hotel if you will, and people came from all around for ceremonies, etc.
Both building alignments and rock art have been found
that show the importance of sky phenomena to those people.
Here's one of them; you're looking from the sort of inside of the largest known kiva -
Casa Rinconada at Chaco Park. This is a fun thing to go see.
It is aligned very precisely with the cardinal directions.
As you can see, you're looking to this T-door opening, and it's directly below
the north star, and you can tell that by the star tracks right, so, it's aligned very well.
But some of the windows are also possibly aligned, and if you look at the little inset that I put
there, that's a picture I took when I went there at summer solstice a few years ago and you see that
little inset there is illuminated. It's illuminated by the rising sun coming through
another window, kind of on the opposite wall. You can go to Chaco at solstice and there's
quite a celebration there. Be forewarned, they limit the number of cars that they allow to go in,
they close the gate, and people line up while it's still well dark, and the first hundred cars
get to go in, and then we all stand around the wall and watch the sun rise,
and it shines through this window and illuminates this other inset. And, possibly these
other insets have other alignments that have not yet been identified. But this is an example
of what would have been a ceremonial kiva, and it would have had a roof on it. So, think how
exciting that would have been, to have the shaft of light come in, and you can tell the time of year by
where it is illuminating the opposite wall. Now that's a principle that is easy to see in
many buildings, even the modern native Navajo hogan is always built facing due east.
And so, how the sun comes in that door during the year and projects against the opposite wall is,
basically, a calendar and they can use it that way. I noticed that in my own house,
how the rising sun comes through the windows, and what part of the wall it goes on
is determined by the season. So, there's a building alignment at Chaco.
Perhaps more famous is a rock art
alignment that was studied by Anna Sofaer years ago. I believe that Brian Bates talked about this
as well, so I won't talk too much about it, but it is a thing that we see in other areas across
the Southwest so it's very useful to understand. In the upper right I have a picture of Fajada
Butte where this was discovered. Anna Sophaer was looking at rock art on the outside of Fajada
Butte around the time of solstice, and she happened to then see in an inner recess this, this spiral.
And the sun during the day came through cracks in these rocks, and at solstice period,
put a dagger of light right through the center of the spiral. Well, was that a coincidence?
Did they put the rocks there, or did they see the shaft of light and then draw the spiral?
Lots of questions, of course. Moreover, at the winter solstice,
two daggers appear on either side of the spiral.
If you see in the main picture I have there that's the winter solstice,
and on the right you see the sun dagger, right through the center in summer solstice.
Well, coincidence or not, it got people studying and looking for more examples of rock art alignments.
We'll come back to that in some other sites, but before we leave Chaco,
you have to take a look at this wonderful set of pictographs.
You can see how astronomical they are; there's a phase of a moon,
there's something that looks like a star, we have a hand, and below there kind of faintly,
and in the inset I've given a figure drawing of it so that you can see it more plainly,
there's this bizarre flaming target thing, which looks a bit like a comet.
So people have speculated that it is a comet.
Moreover, that it could have been an appearance of Comet Halley, because
Comet Halley appeared near in time to a known supernova. So, maybe these two things illustrate
the occurrence of a supernova about a thousand years ago, at a time when Comet Halley did a flyby.
We can't know for certain, but that's the case of many things in archaeology.
What we can know for certain, is that this this set of pictographs shows
the importance of celestial phenomena to these ancient people.
They took the time to paint this on the wall, so they were noticing these things,
and they probably had an important role in their beliefs and thought patterns about the world.
All right, now we're going to move to a little bit of a complicated site. If you go north from Chaco,
you can see where Chaco is there in New Mexico, just across the border into Colorado, there is
Chimney Rock National Monument, which is the northernmost Chacoan site with the Chacoan style
building, but it records an interesting lunar cycle event. And so bear with me, here is complicated
diagram of a lunar standstill. Now the moon also changes its azimuth rising site,
but it goes through what would have been a whole annual cycle for the sun in the space of
a lunar orbit, which from phase to phase as seen from Earth is about 29.5 days.
So, if you watch the moon rise on consecutive nights, you'll see it changing its azimuth rise position.
It does what the sun does, it goes from an extreme point to the north of east when it's rising,
and then back to an extreme point to the south of east, and these points are called the standstill.
You can imagine why the sun is moving from night to night, but then it comes to a
point and it basically stops and then turns around and goes back, so that's a standstill.
But the thing about the moon, the moon's orbit is very near to the orbit of the Earth,
so these standstill positions are kind of close to the solar solstice positions.
But it's not exact, the lunar orbit is five degrees off, and so sometimes the moon goes
farther north of the sun, sometimes it doesn't get as far north as the sun.
And so, these standstills are divided into major and minor standstills.
The moon reaches its farthest range, it's major standstills, the full moon, once in an 18-year cycle.
That's an interesting and quite a subtle thing; you'd have to watch moon risings and settings for
many years to notice where that alignment position is. Would you do that if you were an ancient astronomer?
Well if you were the watcher, I mean it's your job to watch everything come, and go, and rise;
so you'd be doing that all the time and eventually you might notice this.
Well, do we see any evidence of that in a site? And here's this astonishing site at Chimney Rock.
If you look in the lower right inset, you see a kiva, Chacoan building site,
and it is positioned so that if you look between those two spires
the moon will rise between those spires when it reaches its major lunar standstill.
So that's kind of exciting! Lots of studying has been done, and I think it's
probably worth a visit on your tour, to go look at it. Of course, you have to wait once
every 18 years to actually see the event as it was intended, but still a beautiful Chacoan site.
Now, not too far from there, if you go a little west, you'll come to Mesa Verde, which of course
is famous as a National Dark Sky Park that has amazing cliff ruins. But it also has some
archaeoastronomy to it, and so, I thought I would mention it. You might want to stop there,
you can see there it is on the map, and I'll simply mention that the alignments that have been studied
are alignments in Cliff Palace and Sun Temple. Now remember since this, we talked
about the sun coming through the east facing door of the hogan, or through your window,
and then a shaft of light landing somewhere else. Some of the windows in these towers, and alignments
between towers show the same alignment. Is it intended, or is it Manhattanhenge? Not sure.
But, again, who can pass up a trip to Mesa Verde? Whoa! All right, if you go a little further across
the border, right on the border of Colorado and Utah, you come to Hovenweep National Monument
in our tour, and there are some alignments that have been studied there among the towers.
Now, I love the towers of Hovenweep. They're very like the kinds of towers that modeled
the Desert View Tower in Grand Canyon, and of course, that, you've got to go there and see all
the astronomy murals painted there by Fred Cabotie from years ago; there's constellations and meteors
illustrating a lot of Hopi astronomy. But here studies have been done on window alignments
by Ray Williamson. You can read about them in his book Living the Sky,
I think which usually appears in many book stores in national parks.
Take a look for it, and give yourself a chance to stop there and take a look at these towers.
All right circling back down into Arizona, here is kind of my local area, and just above
this map is where Grand Canyon is. If you come down 89 on the right, you'll come to Wupatki National
Monument, and it's one of the nearest sites to Grand Canyon. I believe Brian Bates will talk about,
or did talk about this particular site at Wupatki, called Crack-in-Rock.
I'll show you an example, here again, of a site. Here are a bunch of big dots, and it just so happens
that protrusions in the rock make a shadow, sometimes called a Shadow Dagger, and that dagger
lines up against the dots, as you can see in the inset, at equinox. Now, there's a lot of other things
here, and this is a very recently studied site by David Purcell with Museum of Northern Arizona.
If you want to go see it, it will require a little bit more work. You can't just drive up to it.
It's a bit of a backpack, and you have to go with a guided ranger hike.
You can register for it at Wupatki, and then they will guide you out to the site,
and there's many other amazing pictographs. It is still in the process of being studied for
its archaeoastronomical significance. An interesting site that should be on your lookout.
The last one I'm going to talk about is south of Sedona. So, now we've come,
we've been coming south from Hovenweep, but going down to a fun area you can drive to.
The V Bar V Heritage Site, V bar V was a ranch that owned the land, but there's this amazing
set of pictographs that was recently very well studied, and what you'll see here that's,
let's see, I don't know if you see my cursor, but if you do the rocks here have been placed.
They're not just naturally sitting there, and that's been established through study.
They're here as well, and so, they cast shadows in a very particular direction at a near noontime
solstice illumination. Those shadows, based on time of year, will hit certain pictographs.
Here's a little spiral, I don't know if you can see it, but the shadows will hit that at
winter solstice. There are other symbols along here, and this thing is just chock-full of many
different kinds of pictographs. But if you go to V Bar V Heritage, they'll give you information on
the study of them and their significance. Here's a little map - you come down I-17, 179, right there, I'm
sure you can look it up. All right, well, that's just a sampling of what I'm calling the Four Corners
Ancient Astronomy tour. If you start in at Chaco, you can go up to Chimney Rock, Mesa Verde,
Hovenweep, Wupatki, and come back down to V Bar V, and of course you're going to stop at Grand Canyon.
You may even be doing this near in time to Grand Canyon Star Party, and take
a look at these different astronomy sites. So, just a suggestion, whether you go to any one of them,
or all of them, I hope you enjoy seeing the sky as the ancient people of this region would have seen it.
Last but not least, I want to give a shout-out to the Society for Cultural Astronomy
in the American Southwest. They are also a wonderful source for additional information
on archaeoastronomy of the region. You can become a member or get as involved as you like,
and so I've put their website up there in big font. I hope you have a great enjoyment
of both the night sky and the cultures of the people who used to live here. Thank you.
All right, well, thank you so much David, that was a fascinating talk. Really well-rounded, and I just
very much appreciate that greater region tour, and the way that you formatted that talk for
folks who might be visiting Grand Canyon, and might want to do that larger regional tour.
I have so many questions but just to keep it somewhat brief, if you don't mind,
My first question would be:
How, you've indicated like a few sites here, and given some examples, but how,
can you paint a picture of how prevalent these sites are around
the southwest in general; I mean are we talking about, have you just talked about 80 percent of them,
or are we talking about thousands? What your perspective on that?
I'll have to plead the fifth because I think, the first thing that comes to my mind is,
how little study has been done compared to the number of ancient sites that exist.
If I put them, if I can put them in two categories, rock art sites versus
ancient ruins sites and buildings, you know from grand canyon archaeology, that there are thousands
of ruins, and there are equally large numbers of rock art sites. Now I know that members of
the Society for Cultural Astronomy in the American Southwest are busy, for example, doing a survey
of rock art sites and their alignments. They're just in the beginning of collecting
hundreds and hundreds of surveyed pictures of the rock art sites; there are spirals everywhere.
Now let's sit back a minute with the spiral. There are other spirals that have sun daggers,
and so it makes archaeoastronomers think, "Oh wow, this is kind of a universal solstice sign," right?
Modern tribes say "No," they say "The spiral is our symbol for migration," or at least some tribes do.
There might be others that have different interpretations, so we have to be careful here.
But again, the game is to try to find these sites and then compare them with astronomical
alignments, and I think we're just beginning to exploit the full capacity. There's just a beautiful
new set of tools being constructed at ASU for computer simulations of sites. As you can see,
if we know the azimuth of the solar sunrise at of solstice, we don't have to sit around and wait
for solstice to see where it's going to come from, right? We can model it in a computer, and so the new
software that they're working with will also take photographs of the site and make a 3D
representation of all the elements in the site, and then can project to tell you how different
celestial bodies will impact it. But, this is just in the beginning of operation
and of course there's more sites that are unexcavated than excavated for one thing.
And then, of course, there's also a lot of practices in ancient astronomy that wouldn't
have left a relic, or a mark, like our Hopi sun watcher. He knows where his roof is but, you know,
a hundred years later you're not going to go "Oh, wow, this roof is aligned." You wont know that,
So, my feeling is that we only see the tip of an iceberg, but we may not see the whole iceberg.
I guess that's it for me, I mean, the one tough question I have,
which might not be tough, might be easily answered for you, is how would the, I can
understand how the summer solstice and the winter solstice would have been observationally marked.
How might they have determined the equinox, observationally, for some of these sites?
Yeah, I've always thought about that too because, you know, like I said, I know where the solstice
positions are on my own horizon. There's kind of a large hill in the due east from where I look,
and so I know when equinox is because I'm an astronomer, but I'm always like "Well, where exactly
is it rising, and how would ancient people have known the equinox position?"
For one thing, unlike the standstills at equinox, the rise position is not standing still.
It's changing more rapidly than at any other time of year. I mean, it's moving from
day to day, so if you were trying to pick out, well, what could you do? I mean if we just speculate,
we certainly could go halfway between the two solstice positions, which, of course,
would have been, for equinox rise, would have been due east. One thing Native Americans
are often very good at is cardinal directions. They know, they have a great sense of
literature, and thought about the meaning of cardinal directions;
where things come up, where things set, and so if you look at even symbols, say,
from Hopi symbols you'll see a cardinal direction sign with quadrants that have different associated colors,
that are very specific. So, I would say part of the answer has to be their astuteness about
cardinal directions. They know, and those can come from many other ways, I mean we know there's
the north star that gives us the north, but the sun during the day, the simple gnomon; when the
shadow of the sun is at its very shortest, it is due south. If you have due south and due north,
you can go 90 degrees from either direction. When you construct a hogan you do exactly that:
you construct it according to, I heard a wonderful talk about the mathematics of
constructing a hogan, and it was basically some basic geometry of how you
position all the the pillars for the hogan etc. They know cardinal directions, and I think that
has to be how they determine equinox. What would be its significance, you know,
I'm not sure. I think many Native American tribes don't call the seasons in terms of four.
I think they're right. They have two seasons, and what we call these you know spring and fall,
these equinoxial seasons, are really transitions. Things are changing really fast, and so,
you know it's more logical to a sky watcher and to a native person to say "Look, you've
got winter and you've got summer." Then, when you're in between, you're in between.
You're changing - you're changing fast. That's really not the thing. Those of us who live in
northern Arizona in April know that this is not a well-defined season.
Yeah, yeah.
Yeah, it's snowing, it's 70 degrees. Make up your mind.
Well, it's just like you say, I mean, what you explain there, it's a testament to almost our
questioning this type of determination of equinox, is a testament to what we've
lost as a society in terms of actually being observational sky watchers. We're kind of atrophied.
We rely so much on arithmetic, and geometry, and calculation, instead of
going out and actually, intimately, watching the azimuth, and the change along the horizon line.
That's something that is definitely worth preserving, and just a wonderful thing to do,
as you do at your own house, just knowing the little notches of where the sun rises
in different places, in different seasons, is just a great thing that I encourage everybody to do.
With that thanks so much, David. We really appreciate you, and for those watching,
please tune in to the virtual telescope viewing session premiering right after this talk.
And again, Star Party 2022 is June 18th through the 25th, and hopefully it'll be celebrated on site.
In the future you all can come and meet David, and talk about some of the wonders of
cultural astronomy with him, in person, on site, at a future Star Party.
With that, David, thank you so much, and we hope to see you soon up here at the Canyon!
Sure enough, thank you for having me.