About the time you read this article, the Great Solar Eclipse of 2024 will be about to happen or will have just happened. I will have gone to near Sulphur Springs, Texas, along with my wife, my brother and my sister-in-law. If I have gotten any good pictures of this event, I will share them at a later time because I will need to do considerable processing to stack the images and get the most vivid result.
If you view the eclipse, be sure to wear your solar safety glasses and notice a spectacular effect I haven't mentioned before--the Diamond Ring Effect.
The Diamond Ring Effect lasts only a few seconds so you must be alert to see it. Just seconds before totality, the Moon cuts off a tiny, final slice of the Sun. At the last instant before totality, it appears as if the Sun and the Moon form a diamond ring, just at the edge of the Sun about to be eclipsed. Warning! It is a temptation to remove your solar safety glasses at this point. Do not do this. Even the tiny portion of the Sun visible during the Diamond Ring Effect is bright enough to do serious eye damage. You will be able to see the effect with your solar safety glasses very well, so do not take them off.
When totality happens, then and only then, will it be safe to take off the solar safety glasses to see totality with the naked eye. If you are able, know the time length of totality where you are seeing totality -- it will vary across sites. If you know this time, you will know when it is time to get ready to put the solar safety glasses back on. You may look at totality across its whole time but, again, warning!
There will perhaps be another Diamond Ring Effect just a few seconds after totality ceases. Put those glasses back on -- the Sun is coming back to intense brightness.
While totality is present, be sure to gaze around the rim of the eclipsed Sun. These are the years of highest solar activity (solar activity = Sun spots, flares, prominences, etc.). Looking around the rim, you may see one or more prominences. Prominences are enormous gouts of flame, spouting from the edge of the Sun and they will be bright red if visible. They have various shapes and perhaps you will see a really long one. These prominences, if visible, can be thousands of miles in height, tendrils of super-heated hydrogen and other gases dancing off the Sun's surface.
During totality, you may also notice the Solar Corona. This can only be seen at an eclipse or with a very expensive instrument called a coronagraph. This Corona is a pearly white haze that can extend more than a million miles out from the Sun and it is the Sun's 'atmosphere.' It is made of mostly free electrons and protons, super-heated and streaming far from the Sun's surface.
I have included an image I made of the Diamond Ring Effect so you can be ready for it. I made it during the 2017 eclipse at a position in Oregon. If you want to photograph it, I suggest f/5.6, ISO 100 or 200, at 1/2000th. second. Use a tripod to get a steady image.
We are moving toward the time when many galaxies will be visible in the night sky. I will be discussing this in a later column.
Great luck viewing the eclipse -- above all -- be safe.
David Cater is a former faculty member of JBU. Email him at [email protected].