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I keep hearing that you can go blind during a solar eclipse.

Is the sun actually any brighter during a solar eclipse? This is how the media seems to frame it, and they suggest you need special glasses to view the eclipse.

But after some reading, it seems that the warning is about just not staring at the sun in general, and there is nothing special about the eclipse.

Is this the case?

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  • $\begingroup$ The explanation makes sense, considering this it's not advisable to observe the sun during the solar eclipse $\endgroup$ – Leo Swanson Aug 21 '17 at 4:28
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    $\begingroup$ For more modern myths and misunderstandings about eclipses listen to Skeptoid episode 584 $\endgroup$ – user1569 Aug 21 '17 at 8:04
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The Sun is the same as ever. It's just that people tend to stare at it for long times during the eclipse. A quick glance doesn't do much damage, but prolonged staring could be bad.

Those who see the phase of totality have an additional risk. After the Sun goes completely dark, and it then finally shows up again, some people feel compelled to keep watching that tiny sliver of light without protection for a long time. Don't. When the actual surface of the Sun is visible again after totality is over, it's time to put the googles back on.

Do not use regular sunglasses. They typically don't block the kinds of radiation they should block to allow you to watch the event safely. There are several options here:

Very dark welding glasses. Ask a welder or go to a welding shop. They have these special glasses to protect themselves from the radiation from the welding arc, which is similar to the Sun's radiation. These glasses are numbered to show how dark they are. For viewing the Sun, use the darkest ones, labeled #14. A welding mask with a #14 glass is perfectly safe no matter how long you're looking at the Sun. #13 glass might be safe too for short durations, but it's not recommended. Anything lower than that is not safe.

Goggles made specifically for watching the Sun. There are many kinds of them. As long as they pass the ISO 12312-2 international safety standard they're fine.

I recommend the goggles made of Baader solar film. They show the Sun in its original color (not red, green, orange, etc). There are several kinds here, too; the Baader AstroSolar Silver/Gold Film passes the ISO standard, these are what I use. You can buy them online in various places and they're very cheap.

More info:

https://eclipse2017.nasa.gov/safety

https://eclipse.aas.org/resources/solar-filters

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  • $\begingroup$ Another recommendation is to view it via "pinhole camera". This can be done very simply with as little as a couple of sheets of paper, or a little more elaborately with a shoe box. The idea is to arrange a surface on which you want an image such that the only light falling on it passes through a pinhole. tl;dr: place a piece of paper in sunlight on the floor; make a pinhole in the center of another piece and hold it so that it shades the first piece as completely as possible; you should see an image of the sun from light passing thru the hole. $\endgroup$ – Anthony X Aug 13 '17 at 18:37
  • $\begingroup$ Are you saying it's okay to look at the sun while it's completely eclipsed? $\endgroup$ – Kyle Delaney Aug 21 '17 at 14:40
  • $\begingroup$ @KyleDelaney - a little late for this comment now, but yes, it is completely safe to observe the total phase of the eclipse without using any special device. I have done that 2 days ago during the eclipse. Visually, seems about the same brightness as the full moon, more or less. $\endgroup$ – Florin Andrei Aug 23 '17 at 18:00
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No, the intrinsic brightness of the sun does not change. Part of the sun light is blocked from reaching earth however making the sun appear dimmer or less intense. This has a tendency to cause people to stare at the sun to see this effect. The sun is so bright even a portion of the light reaching your eyes is intense enough to damage them. So do not look at the sun during the eclipse, or any other time, without proper eye protection.

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  • $\begingroup$ And I guess when the stress this during an eclipse, it is in anticipation that viewers will be inclined to stare at it for long periods. $\endgroup$ – ScottF Aug 11 '17 at 16:19
  • $\begingroup$ yes probably. Even short times is dangerous though. Best not to look at all without proper precautions. I can't stress this enough. Even a short duration view is dangerous. $\endgroup$ – jmh Aug 11 '17 at 16:25
  • $\begingroup$ Recommendation noted. I am still just going to double up on sunglasses and glance up for 5 seconds.... $\endgroup$ – ScottF Aug 11 '17 at 17:19
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    $\begingroup$ DO NOT look at the sun with sunglasses. You need the proper solar filters to look at the sun -- unless you want to cause permanent eye damage. $\endgroup$ – JohnHoltz Aug 11 '17 at 17:40
  • $\begingroup$ @ScottF - The local news yesterday did a story on an elderly man who got major eye damage from staring at a previous eclipse when he was a boy. Seemed like a legit story. There's at least one anecdotal piece of evidence. $\endgroup$ – iMerchant Aug 15 '17 at 22:16

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