Look west down any of downtown Toronto's east-west aligned streets at sunset this weekend, and have your camera ready to capture some spectacular images of Torontohenge.
Years ago, astrophysicist Neil deGrasse Tyson coined the term Manhattanhenge. It describes certain days of the year when the setting Sun lines up perfectly along the streets of Manhattan.
Framed by the tall skyscrapers of the New York City borough, this produces an effect similar to what the ancient druids created when they erected Stonehenge in what is now Wiltshire county in southwest England.
Manhattanhenge along 42nd St, June 3, 2008. Credit: Sevtibidou/Wikimedia Commons
Manhattan isn't the only place that sees this kind of phenomenon, though.
Toronto experiences this as well, and — appropriately enough — this has come to be known as Torontohenge.
Sunday, October 24 and Monday, October 25 are the best days to view Torontohenge this year.
On Sunday, we should see a "Full Sun" event. This is where the entire disk of the Sun will be above the horizon as it lines up between the buildings. It will be a "Half Sun" event for Monday, where the Sun will be half below the horizon during the alignment.
According to Ralph Bouwmeester, a Sun/shadow modeller who runs the SunPosition blog, the days leading up to Sunday and Monday will also afford an excellent view of this phenomenon. Thus, this weekend would be a great time to check it out (read on, below, to see our chances of having clear skies).
The best locations to view Torontohenge are perhaps along Wellington Street W, King Street W, Adelaide Street W, and Richmond Street W, in downtown Toronto. On King Street W, outside of Roy Thompson Hall, is especially good. Farther north, Bloor Street W near the intersection with Yonge Street is also a great spot.
This map shows the best streets for viewing Torontohenge from downtown Toronto. Credits: Google/Scott Sutherland
Each of these roads is straight, with tall buildings lining both sides, and has a relatively unobstructed view of the western horizon. Any similar street will produce the desired effect, though.
Sunset occurs at:
6:23 p.m. on Thursday,
6:22 p.m. on Friday,
6:20 p.m. on Saturday,
6:19 p.m. on Sunday, and
6:17 p.m. on Monday.
However, to get the whole experience, plan to be set up at your desired viewing spot at least half an hour before sunset. That way, you can watch as the Sun slowly comes into alignment between the buildings.
CLEAR SKIES OR CLOUDY?
Based on the weather forecast as of Thursday, there's some unsettled weather today, and more cloudy skies starting on Monday.
At the moment, Friday, Saturday, and Sunday look like the days with the best chance of seeing Torontohenge. However, come back for updates or check your local forecast to be sure.
Watch below: How to capture the best sunset photos
WHAT'S GOING ON HERE?
Throughout the year, our planet's tilt causes the Sun to change position in our skies. From day to day, the Sun gets higher in our sky from winter solstice through summer solstice. It then gets lower in our sky, day by day, for the remainder of the year. So, with each sunrise and sunset we experience, we see the Sun at a different point along the horizon than it was the day before.
This 'solargraph' image captures the Sun's path across the sky, day after day, between the dates of February 28 and June 20, 2016. Credit: Bret Culp (Used with permission)
Noticing this trend, ancient peoples such as the druids set up monuments in such a way that the Sun would line up with them on particular days of the year. This is typically on the four significant astronomical dates — the winter and summer solstices and the spring and fall equinoxes.
Cities such as New York and Toronto weren't built with these alignments in mind. Instead, the local geography dictated how they developed. For Manhattan, it was the orientation of the island. For Toronto, it was the shape of the lakeshore. However, by coincidence, it turned out that there were specific dates where the rising or setting Sun would line up perfectly with the city's streets. The effect became even more 'henge-like' as the buildings were built taller and taller, as they framed the alignment perfectly.
In Manhattan, the setting Sun lines up along the city's streets on May 29/30 and July 11/12. For Toronto, both the rising and setting Sun will line up along the city's downtown core. Thus, Torontonians can see sunset alignments around February 15 and October 25, and sunrise alignments around April 19 and August 23.
A CALL FOR CAUTION
With the setting sun shining straight down the streets of Toronto, the glare will undoubtedly make things difficult for those who are behind the wheel.
Whether the Sun is directly in your eyes as you drive west or in your rear-view mirror as you drive east, extra care should be taken during the afternoon commutes for the rest of this week and for a few days after Torontohenge as well. That way, we can all arrive at our destinations, safe and sound.
If you are out in downtown Toronto to see Torontohenge for yourself, be very careful when viewing. There is a great temptation to step out into the middle of the street to capture the perfect view. Still, please be mindful of traffic and the potential impact of glare on the ability of any driver to see you.