Why is it dangerous to look at a solar eclipse?

[GreyWanderer]

If it's not bright enough to make you automaticly turn away, why does it then damage your eyes?

[ToSeek]

I don't think there are any pain nerves in the eye itself, so you can damage it without realizing you're doing so.

In any case, there's nothing special about the Sun during an eclipse. The warnings are given because people are more likely to look at the Sun during one. It's dangerous to stare at the Sun at any time, and multiply so to do so through any light-gathering device like binoculars or a telescope.

[Glom]

It's also a case that your eyes stop up during an eclipse because the sky's dimmer and the diamond ring can then be dangerous.

[MHS]

I watched the total eclipse of August 1999 in here in Europe and we were told that we could look at the sun during totality without any protection. I'm talking about internet, newspapers, national television here. Then after the event I heared that it's better not to do it at all. But then my question is: how to watch a solar eclipse? During totality the sunlight is to weak to see through the special glasses...

Anyway, it's almost 4 years later now and I can still see /phpBB/images/smiles/icon_smile.gif

[ToSeek]

On 2003-03-05 16:47, MHS wrote:
I watched the total eclipse of August 1999 in here in Europe and we were told that we could look at the sun during totality without any protection. I'm talking about internet, newspapers, national television here. Then after the event I heared that it's better not to do it at all. But then my question is: how to watch a solar eclipse? During totality the sunlight is to weak to see through the special glasses...

Anyway, it's almost 4 years later now and I can still see /phpBB/images/smiles/icon_smile.gif


During totality is fine. However, anytime before or after totality is risky, particularly because, as Glom notes, your pupils are more open than they would be in full daylight.

[tracer]

On 2003-03-05 15:23, Glom wrote:
It's also a case that your eyes stop up during an eclipse because the sky's dimmer and the diamond ring can then be dangerous.
"Your eyes stop up"? I think you mean your pupils dilate.

[tracer]

On 2003-03-05 16:47, MHS wrote:
Anyway, it's almost 4 years later now and I can still see /phpBB/images/smiles/icon_smile.gif
My dad wasn't quite this lucky. He stared at a partial eclipse for a little while when he was young, and now he has a permanent "burned-out" area on one of his retinas that is shaped like a partial solar eclipse.

[ljbrs]

I have used welders' *Shade 14* welding glass in welders' shields when watching a Solar eclipse. I have even looked directly at the Sun through them without doing any noticeable damage. Welding shields with *Shade 14* welders' glass can be purchased in stores which cater to welders. Make certain it is *Shade 14*, though. Then again, some people think that is also dangerous.

ljbrs /phpBB/images/smiles/icon_confused.gif

_________________
"There is in the universe neither center nor circumference." Giordano Bruno Born 1548. Torched 1600.

<font size=-1>[ This Message was edited by: ljbrs on 2003-03-05 19:10 ]</font>

[daver]

On 2003-03-05 18:46, tracer wrote:


On 2003-03-05 16:47, MHS wrote:
Anyway, it's almost 4 years later now and I can still see /phpBB/images/smiles/icon_smile.gif
My dad wasn't quite this lucky. He stared at a partial eclipse for a little while when he was young, and now he has a permanent "burned-out" area on one of his retinas that is shaped like a partial solar eclipse.


During the last partial eclipse, i made kind of a projector out of a camera tripod, a mirror, and an envelope with a hole ripped in it. I got a fuzzy image (it's fun to play with stuff during a partial eclipse. Almost anything can make a pinhole camera), which was fine for a partial eclipse, but i'd like to do a bit better. At the time i poked around a bit trying to find plans for a projector that could be build on the cheap with stuff likely to be found around the house (or generally available for little money); i did't find anything, but i didn't spend that much time at it and might have missed an obvious site. Anyone have any suggestions?

[johnwitts]

I used a borrowed digital camera for the European Eclipse. Good for looking at the Sun before and after totallity, because there's no way you can hurt your eyes. The camera seemed to survive the experience as well... /phpBB/images/smiles/icon_smile.gif

[Hale_Bopp]

Actually, trees make great pinhole projectors. Just look at the ground and the leaves will act as pinholes projecting hundreds of images of the Sun on the ground.

I know it seems unnatrual to look at the ground during an eclipse, but try it...it's pretty cool /phpBB/images/smiles/icon_smile.gif

Rob

[The Bad Astronomer]

Try here (http://mintaka.sdsu.edu/GF/vision/Galileo.html). This is a great essay on solar retinopathy. Also, I hear there is a chapter in the book Bad Astronomy (http://www.badastronomy.com/book/index.html) about this.

<font size=-1>[ This Message was edited by: The Bad Astronomer on 2003-03-05 20:28 ]</font>

[daver]

On 2003-03-05 19:46, Hale_Bopp wrote:
Actually, trees make great pinhole projectors. Just look at the ground and the leaves will act as pinholes projecting hundreds of images of the Sun on the ground.

I know it seems unnatrual to look at the ground during an eclipse, but try it...it's pretty cool /phpBB/images/smiles/icon_smile.gif

Rob


Our trees weren't positioned well for shadows then. I remember a B&W picture posted on usenet a long time ago of shadows from a tree during a partial eclipse. Lots of fun.

When we were viewing the eclipse we had two dads and two 5-year olds. The moms were inside watching tv. The dads were outside making O's with their thumb and forefinger and looking at the results, looking at the shadow cast by a piece of particleboard with holes drilled in it, and generally cavorting and making fools of themselves. The five year olds were outside (because it was EDUCATIONAL) but bouncing a ball against the side of the house.

[Irishman]

I've never really been able to tell about eclipse in shadows from leaves. The openings are already irregular.

However, my dad made a projector out of his telescope. You point the telescope at the eclipse, and aim the opening from the eyepiece (without an eyepiece) at a wall or screen to provide the viewing surface.

[GreyWanderer]

On 2003-03-05 20:27, The Bad Astronomer wrote:
Try here (http://mintaka.sdsu.edu/GF/vision/Galileo.html). This is a great essay on solar retinopathy. Also, I hear there is a chapter in the book Bad Astronomy (http://www.badastronomy.com/book/index.html) about this.

<font size=-1>[ This Message was edited by: The Bad Astronomer on 2003-03-05 20:28 ]</font>


Thanks. That essay cleared it all up.

[Comixx]

I loved looking at all the projected partials on the ground during the last eclipse.

Also, in relation to Glom saying "your eyes stop up.." that is a photographer's term used to describe opening the aperture of a lens wider (or changing the f/stop to a lower number). At least, that is what I assumed he meant /phpBB/images/smiles/icon_wink.gif

<font size=-1>[ This Message was edited by: Comixx on 2003-03-06 05:16 ]</font>

[Glom]

Yep that's it. I like that term. /phpBB/images/smiles/icon_wink.gif

[calliarcale]

*reads article*

Galileo went blind from cataract and glaucoma! ACK! I've been suckered by another urban legend! I used to believe that he'd gone blind discovering sunspots, but now I know better. Thanks, BA!!! It's a good article too. It clears up a lot of the details for me.

[gethen]

Several years ago, during a partial solar eclipse in this area, I was told that it could safely be viewed through exposed radiographic film that was improperly developed so that it was totally black. I tried this and could see the eclipse fine, but have since wondered if I was smart or just lucky.

[David Hall]

One of the best ways to view an eclipse is with a pair of binoculars. Use them to project an image of the Sun onto carboard or something (hint, use something dark. Light surfaces create a lot of glare). You get two clear images. I used my pair a few months ago to check out a large sunspot.

I'd love to get a real mylar or welding glass viewer though. I want to be able to look at the Sun directly for once. There just seems to be something missing when you only have a roundabout way to observe.

[The Bad Astronomer]

On 2003-03-06 11:36, calliarcale wrote:
*reads article*

Galileo went blind from cataract and glaucoma! ACK! I've been suckered by another urban legend!

I was the tech editor for the book "Astronomy for Dummies", meaning I was supposed to make sure all the astronomy was right. This myth was mentioned as fact, and it went right past me, even though I had already talked to Andy Young about it. I was truly embarrassed! As far as I know, it's the only content error in the book. Steve Maran is a really good writer.

[calliarcale]

That makes me feel a lot better. Thank you. /phpBB/images/smiles/icon_wink.gif Mistakes can slip by even the best of us, obviously, if they can sneak past you!

[Kiwi]

I looked at the uneclipsed sun through binoculars and saw it in 3D as a round ball, back in the early 90s when there were lots of sunspots. I researched the subject to find out what filters were safe, and, besides the welding goggles mentioned above, there was also a particular form of mylar (available only in the U.S.A. at the time) and the one I used -- fully exposed, developed and fixed CONVENTIONAL (silver-based) 120 black-and-white roll film, such as FP4, Pan-F, Plus-X, Tri-X etc., taped over the front lenses of the bunoculars.

Finding the sun isn't easy because the sun is the only thing visible and it's deep, dark orange. But well worthwhile.

Dunno how much truth there is in this, but apparently 24-year-old Dimbeswar Basumatary of Balimari, Assam, India, can spend hours gazing at the sun without blinking. He's been doing it for five years. An opthalmologist from the Sankardev Netralaya eye hospital says Basumatary has good colour vision whith no problems -- so far. (Islamic Republic News Agency)

[Kaptain K]

One of the best ways to view an eclipse is with a pair of binoculars. Use them to project an image of the Sun onto carboard or something (hint, use something dark. Light surfaces create a lot of glare). You get two clear images.
You can get a single image if you cover one of the lenses with a handkerchief. I did this in the late sixties and at one time had the pictures to prove it.

[honestmonkey]

Well, since we're recounting eclipse stories, here's mine.

It was a partial eclipse in 1996? 97?, maybe a bit before. The large evergreen bush out front made a pretty good projector. Lots and lots of little cresents all over the ground. It was an eerie experience. Everything seemed dimmer than it should be, but in the wrong way. It also seemed more quiet than usual.

All in all, a lot of fun.