Tag Archives: sunrise

Summer Solstice 2017

Today is the summer solstice, so I watched the sunrise at Virtual Avebury and then took a walk around the completed simulation. I love going back here, particularly on days like today 🙂

Just as an update, I submitted my dissertation in early May and should be getting the results back very soon – gulp! As long as all is well, I’ll post some parts of my dissertation on this blog, although I’m writing a book chapter from it too, so I’ll need to be careful about not publishing anything I’ll be incorporating in the chapter.

Sunrise at The Cove

IMG_1651 (640x480)The arrangement of stones in the northern circle of Avebury is known as “The Cove”. It originally would have consisted of 3 stones, of which only 2 remain standing today as shown in the picture on the left. The third stone was to the left of the megalith in the centre and the arrangement would have created a box shape with an open side pointing north east, i.e. in the direction the picture is pointing. The smaller stone you can see to the left of the central stone is all that is left today of the circle that surrounded The Cove. There were some other stones inside the circle, and geophysical investigation has suggested that there may have been a row of smaller stones facing the open side of The Cove, but this isn’t yet known for sure.

As I’ve been constructing virtual Avebury, the northern and southern circles have been feeling more and more important, so I erected the Obelisk in the southern circle, which I discussed in the last post, and now I’ve put up the 3 stones of The Cove in the northern circle to see how they look, shown in the picture below. The stone pyramids are markers for stones I have yet to make and place.

Cove sunrise 1

As with every new stone setting I make, I’m fascinated by them! As the open side faces the position of the rising sun at the summer solstice, I thought I’d try out some of the sky preset effects in Firestorm (the viewer I use) to get the sun to rise at its summer solstice position at virtual Avebury. To do that, I checked the time of sunrise on 21st June this year (OK, not strictly correct as it should be 4.5K years ago but it’s near enough!) which was 03:43 GMT. I then went to the NOAA Solar Position Calculator and entered the date as 21st June, the latitude and longitude for Avebury (51.4295N, 1.8530W) and the time of 03:43. The sun position calculator then gave me the solar azimuth as 49.29, i.e. the sun’s position on the horizon measured in degrees clockwise from north at that time, location and date. However, the elevation above the horizon at that time was -0.06, so whilst that may be technically sunrise, it wouldn’t be visible as a spectacular rising above the horizon, so I tweaked things until the elevation was 1, which actually made very little difference to the time (03:55) and the azimuth setting (51.33). So far so good!!

Firestorm has the facility to change the position of sunrise and sunset from its default of rising dead east and setting dead west. In the sun controls (the slider known as the ‘easting’ control) east is set as 0, as the sun rises dead east at the equinoxes (roughly 21st March and 21st September). Running the slider along its length moves the sun through 360 degrees around the border of the sim, ending up east again at 1.0. North is set as 0.75. As the azimuth setting I’m looking for is 51.33 degrees east of north, I took that away from 90 to find out how many degrees north of east I’m looking for. Answer = 38.67. I then worked out what decimal fraction of 360 that is (answer was 0.105), and then subtracted that from 1 to find out what I had to slide the easting control to for midsummer sunrise. Still with me?? 🙂 Anyhoo, 1 minus 0.105 is 0.895, so that’s what I set the sun position to be in Firestorm. And hey presto!

Cove sunset 3_001

Here is the result. The sun rising directly into the mouth of The Cove. I’m blown away by this! Reading some of the literature on theories relating to astronomical alignments at Avebury, writers like Burl (2000) are unconvinced of The Cove’s orientation to the rising summer sun because the width of the “sightline” would make it inaccurate. But I think this completely misses the point. The builders of Avebury were not building an observatory, where sightlines and accuracy matters, but were more likely building monuments that had particular meanings for them. The days before and after the solstice, when the sun would still fill The Cove on rising, may have had special significance. Perhaps that period of several days was a festival of some sort. In any case, we need to be very careful about overlaying post-Enlightenment, western scientific criteria onto our interpretations of structures that may have had very different meanings to their builders. Here endeth the first lesson 🙂

If you’d like to visit virtual Avebury you’re welcome to. Simply go to Kitely.com, set up a free avatar account (remember your u/n and password!) and then download the Firestorm viewer (Google ‘Phoenix Firestorm’). Open the viewer and enter your u/n and password and when you have rezzed on the welcome site, click on the search magnifying glass in the viewer and enter EIC at UWE. Teleport there and you’ll land at the visitor centre. Look at the top of your screen and click on Avatar, then Preferences and then Graphics. Set your draw distance as far as possible (Avebury is a big sim!) and then feel free to have a good look around. If you’d like to hear the soundscape too, just click on the movie camera icon in the top right of your viewer. Virtual Avebury is still very much still under construction, but I’d love to get as much feedback as possible as I go along – evaluation is one of the things I need to do lots of for my Advanced Dip dissertation! I’ve set the sky to be perpetual summer solstice sunrise at the moment, so I’d be particularly glad to get feedback on how it makes you feel.

P.S. The horizon hills are being made as a mesh sculpture by my genius collaborator Aaron Griffiths, in New Zealand. Looking fab already, Aaron!


Burl A. 2000 The Stone Circles of Britain, Ireland and Brittany. London: Yale University Press.