Several people have lately asked me about what exactly to look for during a total eclipse. So, if you’re traveling to this one on August 21, or might see one of the upcoming totalities – in Chile in 2019 or 2020, or in Australia in 2023, or here in the Northeast in 2024 – save this page.
Totality lasts just two-and-a-half minutes this time, and four minutes in 2024. But the real spectacle starts about five to ten minutes before totality begins, so be aware of the time of totality at your location and keep track of the time.
During the hourlong partial eclipse, you need continual use of your eclipse glasses or filter. But 50 minutes in (or ten minutes before totality), put the filter down and pay attention to your surroundings. Sunlight is now emanating exclusively from the solar limb, its edge, and this imparts an otherworldly illumination.
Ordinary familiar objects like houses and cars now seem bizarre. Colors look more saturated and contrast is boosted. Shadows are stark. Starting about five minutes before totality, the light on everything is visibly reduced, seems more yellow, almost orange; and the shadows of bushes or trees now contain countless bizarre glowing crescents. Notice how the temperature is dropping. Look at the reaction of animals.
Take a look at the Sun through your filter now. The Sun, which has looked like a crescent for some time, now has that crescent shrinking into an extended point.
Look again at the ground around you. Two minutes before totality, all white surfaces (or a sheet, if you’ve spread one in front of you) may suddenly be filled with eerie wiggly black lines. These are the legendary shadow bands. They cannot be photographed. Any video or still picture you take will later show no sign of them!
At one minute before totality, the shadow bands reach their maximum display, the light on everything is most stark and the illumination sharply fades. As the light drops further, start taking quick glances at the Sun directly, without a filter. It’s important that these be momentary, half-second glimpses, because the Sun is not yet safe to stare at.
You are looking for the diamond ring effect. You’ll know it when you see it: a single point of sunlight on the edge of the suddenly visible black Moon, with the solar corona now surrounding the black Moon. Take only quick glimpses of this at a time. And if instead you still glimpse full sunlight, look away immediately and try again 20 seconds later, with another half-second glimpse.
The purpose of all this is to catch totality the moment it begins, and not to miss any of it. When totality begins, no direct sunlight remains – just the ink-black New Moon surrounded by the creamy-but-dim glow of the solar corona. Check your timepiece to confirm. Totality has begun.
Now you can stare at it. Indeed, during that first minute of totality, point binoculars at the eclipsed Sun and look for deep-pink flames shooting from its edge. These are prominences: geysers of nuclear flame.
Using naked eye or binoculars, look for structure in that glow surrounding the Moon. Any fine filaments or lines are the magnetic field lines of the Sun: a wondrous sight that is normally invisible.
The corona with its filamentary structure, and the pink prominences, are the main totality features you are looking to observe. But you will also feel an astonishing, unique sense – or vibration, or presence – to the whole thing. It will be like nothing else you have ever experienced in life. Let this experience in, savor it, as opposed to intellectually trying to figure it all out.
Use binoculars only during the first half of totality, because you don’t want to accidentally get any direct returning sunlight into your eyes through the binoculars when totality ends. You might also look around the sky and look for any stars to be out. Certainly, Venus and Mercury will be there, with Venus the brightest.
Don’t worry about your surroundings. You don’t need to be viewing from a mountaintop or some other place of natural beauty. The totality will grab your focus and be a complete package of unspeakable beauty. The foreground you choose is nice, but not vital to the experience.
One important tip is not to spend much time with photography. Eclipse experts must bracket their images by using a range of exposures and f-stops. They use at least a 200 mm telephoto, and usually a 400 mm or even more magnification – and of course a tripod. And even then, a lot of fancy processing and image combination is needed afterward. People who spend their totality minutes fiddling with their f-stop dials always regret it afterward. So, know that expert images will be available after the eclipse, and they will be much better than anything you can create. Don’t even try.
Another factor is your soundtrack. You will find totality to be one of the most sacred experiences of your life. I think it’s best experienced in silence. But some enjoy the excited chatter of a group, which invariably includes commentary and exclamations. It’s not bad per se, but know that you won’t get a second chance. So decide ahead of time what you want. Me, I inform our tour members that I will be unavailable during totality. If you’re in a large group, decide ahead of time whether you to observe it with silence and one-pointedness, or in a matrix of conversation.
Another diamond ring will mark the end of totality. Some say you shouldn’t watch it, but every astronomer I know does indeed watch it, including myself. However, that brilliant spot of returning Sun, the diamond, grows more and more intense, and use common sense to stop watching it after a very short time, after which you must exclusively use your solar eclipse glasses again.
In practice, totality is so astounding, few people bother to observe more than a few minutes of the hourlong partial eclipse that appears after totality. Instead, everyone tries to recall that wondrous thing they experienced. But they can’t. The magical feeling fades, and does not return until the next totality you travel to see – at least one year later.