A total solar eclipse is coming to Mexico, the US, and Canada on Monday, April 8, 2024. Its path crosses northern Mexico, then moves from Texas to the Midwest, southern Ontario, Quebec, Atlantic Canada, and Newfoundland. I’m fascinated and amazed by solar eclipses. I travelled to Manitoba in winter 1979 and Baja California in summer 1991 to see them. This one will be almost on my doorstep, so I will be sure to see it. In this post, I’ll explain why.
Some Technical Background
This is a map showing the track of the eclipse, with the zone of totality between the red lines. Cities where the eclipse will be total include Mazatlan, Durango, Dallas, Indianapolis, and Buffalo. Several major cities are just on the edge of the zone of totality, including Austin, San Antonio, Columbus, Detroit, Toronto, and Montreal. The big difference between a total and a partial eclipse is that the sun is completely covered by the moon’s shadow in the former but not the latter, which dramatically affects what you see.
What you See is What you Get
A total solar eclipse is a unique natural phenomenon, with a panoply of incredible sights unfolding in the sky and on the ground. When the eclipse is partial, the moon is casting an ever-growing shadow on the sun. But the sun’s overall light is so bright, you see little reduction in ambient light. In effect, the reduction in sunlight isn’t linear: the moon covering half the sun reduces sunlight by much less than half. To look safely at the sun when an eclipse is partial, you must use mylar eclipse glasses.
It takes about an hour from the time the moon begins to throw a shadow on the sun to the point when major changes start to happen. The 10 to 15 minutes before totality are an eerie and quickly evolving spectacle. You see darkness gathering much faster than at sunset. But it is different from sunset because the sun isn’t low in the sky, and shadows aren’t lengthening. The temperature is dropping rapidly. Some diurnal birds and animals are retreating, and nocturnal ones are emerging.
Through your eclipse glasses you see that the moon is covering most of the sun, which is diminishing to a thin sliver. Then for a few moments you see Bailey’s Beads, a crescent of points of light as the sun’s rays peak through lunar valleys. After that comes the diamond ring effect, with Bailey’s Beads on one side, and a last burst of direct sunlight on the other side. On the ground, you can see the moon’s shadow rushing towards you at 8000 km. per hour, bringing sudden darkness.
When the eclipse is total, the moon completely blocks the sun, and it is safe to remove eclipse glasses and directly look up at the sun’s ever-changing corona, in shades of silver, blue, and pink. You can also see solar prominences, immense bursts of fiery gas leaping from the sun’s surface far out into space. Looking around you, it is very dark where you are standing in the moon’s shadow, but the horizon all around you is in bright daylight.
When totality ends, the process reverses itself. The moon’s shadow rushes away from you and daylight rushes back to you at 8000 km. per hour. Putting on your eclipse glasses, you see the diamond ring effect and Bailey’s beads once more. Soon the sky’s brightness returns, the temperature rises, and animals resume their normal behaviour. Anti-climactic as it might be, you can use your eclipse glasses to watch the moon’s shadow recede completely from the sun.
Clouds Got in the Way
The major disrupter to viewing an eclipse is clouds. In Manitoba it was a bright cloudless mid-winter day. Baja California is a desert and therefore an ideal setting to view an eclipse. The astronomers who led our eclipse-viewing group selected a spot that was on the line of maximum totality, but clouds rolled in from nearby hills and we saw little of the eclipse. People who stayed at poolside at the hotel saw all 7 minutes of it, close to the maximum possible for an eclipse. (You need an astronomer to explain why this is the maximum.) Long-term cloud cover data show that locations in Mexico and Texas have the highest probability of sunshine, between 60 and 70 percent. In southern Ontario and upstate New York, the probability is in the range of 40 to 50 percent. It will be a gamble.
I’ll refer to Gordon Lightfoot’s song in this blog as I also did in a recent one. Toronto is just outside of the zone of totality. Watching the partial eclipse for over an hour with eclipse glasses and not being able to remove them for the glorious moments of totality is the epitome of unfulfilled edging. As Torontonians (like residents of Austin, San Antonio, Columbus, Detroit, and Montreal) become more aware of the difference between a partial and a total eclipse, they will want to take a short drive into the zone of totality. The roads around these cities may be very crowded on April 8.
After checking out more detailed information about Ontario cities on the path of totality, I’ve decided to go to Niagara Falls to see the eclipse. Niagara Falls will have totality of close to 4 minutes, as long as anywhere else in southern Ontario. It will be very dramatic to see the eclipse in such a dramatic setting, If not at the falls, there are lots of open areas (Queenston Heights) and shorelines to watch the eclipse. I’ve made a hotel reservation for Sunday and Monday nights and I’m returning to Toronto on Tuesday to avoid the congested highways on Monday. I imagine Montrealers will think of heading to the Eastern townships, and I’m sure there are similar options in Texas, Ohio, and Michigan.
As for my trip to Niagara Falls, I am aware of Oscar Wilde’s cynical assessment of it as “the first disappointment in the married life of many Americans.” I hope it won’t be the second disappointment in my life as an eclipse-chaser. But I would be much more disappointed if the eclipse was visible and I didn’t go such a short distance from home to see it. And, of course, just being there and sharing whatever happens with other eclipse-watchers will be a great experience. If you haven’t considered it, I hope you will. And if you do, I encourage you to get started immediately on making plans.