We hear about this every time. Don’t look directly at the eclipse, you could go blind. Does it really happen? Some damage maybe, but I’ve known people stupid enough to arc weld without a helmet, they were in pain, probably lost some vision, but didn’t go blind. If it was that easy huge populations must have gone blind in times past.
My late father-in-law looked at an eclipse (partial) through a telescope when he was a stupid kid, and permanently burned an image of the sun on his retina. It did not blind him exactly, at least he could still read and of course he had the other eye. It did keep him from flying as a pilot when he was in the army air guard (or whatever it was, before it became the USAF).
I don’t know, with bare eyes you can look at the sun for a second or two without going blind, so I’ve never been sure why an eclipse is different. Assuming you’re not looking at it through a telescope. But on the other hand, why risk it?
It isn’t different–that’s the problem. People are more inclined to stare at the sun during a partial eclipse because (a) it’s interesting; and (b) the sun isn’t quite as blindingly bright so it doesn’t feel quite as immediately painful. But, it’s still dangerous. I have my doubts that anyone has ever gone totally and permanently blind, but still, don’t look at a partial eclipse without protection.
When my dad was in his fifties he discovered that he had either lost his peripheral vision in one eye / only had peripheral vision in one eye (can’t remember which) due to looking at an eclipse when he was a kid.
The other eye had been compensating so it only came to light (heh!) decades later.
It is different. During a total eclipse, the sky darkens. So your pupils open up to a lower f-stop. So your eyes become all the more vulnerable to whatever happens when you look directly at the eclipse.
Famous geodicist William Lambton lost vision in one eye by looking at the sun through the telescope of a theodolite, although I don’t believe it was during an eclipse. No doubt it could have happened, if someone used an instrument to watch the eclipse as the sun starts to come out again.
Looking at the sun is a BAD THING, don’t get me wrong, during the partial phases of even an eclipse can harm your little eyes. Don’t do it, don’t try without #12 welding glass.
However, during totality the sun is completely blocked and it’s safe to observe the corona by directly looking. It gets really dark and stars come out and it’s just like night
The logic is that in a late partial phase there is only a thin crescent of sun visible. The surface brightness of the crescent is still full power - but the total brightness of the sun is obviously much reduced. This reduction seems to be enough to avoid the pain/bright light reflex causing people to look away. So it is possible to stare at the crescent for some time. However since the surface brightness of the crescent is undiminished it is quite capable of burning a neat crescent shaped hole in your retina. Probably right in the fovea - which is seriously bad.
Phil Plait has a section about this in his book Bad Astronomy and you can read the relevant text here on Google books. The short version is that most people can look at the uneclipsed sun with the naked eye without having to worry about damaging their eyes, though some people can experience temporary problems. He writes, “[N]ever has anyone had a total loss of vision from solar retinopathy.” He goes on to explain why looking at the sun during an eclipse is more dangerous than looking at the uneclipsed sun, largely because the pupil dilates as mentioned by Segenoid above.
I looked at the sun the other day just before sunset. The sun was near the horizon, reddish and obscured by clouds. I looked just a few seconds at a time. Is that okay?
It’s not perfectly safe, but near the horizon your risk is much diminished. People tend to places during an eclipse where the sun is high in the sky, and this is where the mischief comes into play.
There’s nothing harmful about looking at an eclipse during totality. You are merely seeing the corona, rather than the sun itself. The danger is during the partial phases, when the sun is visible.
Exactly, and it doesn’t matter how temporary the problems are looking directly at the sun, it would be a shame if such problems occur during totality … it’s only a few minutes long at best.
The answer to the OP is no, because direct viewing of the sun doesn’t cause immediate blindness. It causes damage that accumulates over time.
I recall a story from the early 1970s about a young woman who lost her sight observing one of the full eclipses in that era, only to recover it suddenly months to a year later. No recollection of details, it was one of those local-paper feature stories and thus not necessarily ready for JAMA writeup…
Am I correct in recalling that there were several total or near-total solar eclipses (visible across NA) in the early 1970s, an unusual cluster occurring only every few decades?
February 26th, 1979, along the Colombia River Gorge. Yup, 38-1/2 years later we’ll have another one (August 21st, 2017)
My recollection is from late grade school, maybe 1971-2. What eclipses would have been visible from Northern California in that era?
I vaguely remember the '79 one, but that was a… weird year.
That website gives 40 solar eclipses visible from Sacramento, CA, during the 20[sup]th[/sup] century, all partials … July 10th, 1972?
