2017 Total Solar Eclipse

[zapatos]

On August 21st of this year a total solar eclipse will cross the United States. Luckily for me my home will be in the path of totality.

 

The path of totality is about 73 miles wide. I am about 20 miles from the center line, and am trying to decide whether or not to move closer to the center line.

 

An advantage of being on the center line includes the fact that at the center totality will last about 160 seconds, while at my home totality will only last about 115 seconds.

 

Disadvantages of traveling to the center line include the traffic, crowds, and an unknown environment. Of course, the crowds could potentially enhance the experience.

 

One thing in particular I'm wondering about is if totality looks different on the center line than it looks 20 miles from the center line. Specifically I'm wondering if being closer to the 'edge' where the sun is not completely blocked will degrade my experience. Will it be noticeably brighter at my home than at the center line?

 

I'd love to hear any experiences anyone has had with total solar eclipses, tips on how to best experience it, or anything else of interest. I'm a total eclipse virgin and I want this to be a day to remember.

 

 

[Klaynos]

I experienced totality close to the edge of the zone around the year 2000. I didn't travel. I'm glad I didn't travel. It was a bit weird and I might feel differently about it now I'm older.

[swansont]

Don't look at the sun without proper eye protection. Sunglasses are not proper eye protection.

[Delta1212]

Don't look at the sun without proper eye protection. Sunglasses are not proper eye protection.

What about peaking through the cracks between the fingers on my up-raised hand? Edited June 30, 2017 by Delta1212

[Manticore]

When I was young, I smoked a piece of glass with a candle and watched an eclipse through it - worked perfectly.

[beecee]

I was lucky enough to see a total solar eclipse in November 2012 at a place called Palm Cove near Cairns in Queensland Northern Australia.

I was simply using a shade 10 welding glass. Pretty awe inspiring to say the least, particularly before totality and just after totality.

My next item on my bucket list is to see a Annular solar eclipse.

[Janus]

This will be my second chance to see a total solar eclipse. With the 1979 one I lived in the zone of totality. Unfortunately, it was in February, and in the Pacific NW, as per usual for this tie on year, it was cloudy.

It was able to snap one picture while hanging out of the passenger window of a car driving down US 30 chasing a gap in the clouds:

 

Taken with B&W film and developed/printed in the dark room I had set up in my Mom's laundry room. It was not a telephoto lens, so I had to blow it up quite a bit, which resulted in the print being grainy.

 

 

I'll have to drive several miles South to catch this one in totality, and I'm hoping for clear skies.

[iNow]

I'm trying to convince my wife that this is worth it. We have a four year old and an 8 week old. Travel is hard, but it's worth it, right?

I've been gaming out the maps. I think my best bet is Cameron, Missouri. There's even a sweet place called Wallace State Park that we could potentially use as our viewing perch. It's about a 2 hour drive absent traffic. 

I don't want to miss this. I don't want my 4 year old to miss this. I don't care about new movies, or concerts, or sporting events, or even new iPhones... but I care about this. 

I also want my wife who's nursing our kiddo and waking up multiple times per night and changing countless diapers per day while I work and who's the proverbial button holding us all literally together to feel this is worth it.

Barring the obvious (potential stormy skies, overcast day, highway traffic), it is worth it, right? Of course it is. Now, hopefully I can successfully convince her of the same. 

Edited August 5, 2017 by iNow

[zapatos]

Everything I read about it tells me it is not to be missed and is an unforgettable experience. Once people experience it, they often travel again and again to get another fix. I haven't been this excited in a long time.

[iNow]

I, of course, could always make the journey to witness it myself. I just want my girls with me. At minimum, I want my first born there by my side. She's at such an amazing, curious, creative age right now. 

[Sensei]

On 6/30/2017 at 11:51 AM, swansont said:

Don't look at the sun without proper eye protection. Sunglasses are not proper eye protection.

Take two polarization filters, overlap them together, and rotate one to adjust amount of light which is passing through them.

[beecee]

I was in Cairns [Palm Cove to be exact] in November 14th 2012 for the solar eclipse. I used shade 10 welding glass, although since that time I have read where they recommend to use shade 14. It was certainly unforgettable and stunning with totality lasting around 2 Minutes....

ps: Eyes still OK despite using shade 10.

 

 

Edited August 5, 2017 by beecee

[zapatos]

39 minutes ago, iNow said:

I, of course, could always make the journey to witness it myself. I just want my girls with me. At minimum, I want my first born there by my side. She's at such an amazing, curious, creative age right now. 

I forgot you were in Iowa. You used to live in Texas, right? One of the things getting me excited is reading about the first-person experiences. Finding some good articles by people who describe what it was like for them may get your wife excited the trip. I'd be tempted to drag my family along whether they wanted to go or not. I think they'd thank me later.

Quote

You do not see a total eclipse – you experience it. There are changes above you, around you, and within you. 

But here’s the thing – most people do not understand how incredible it is.  It is a strange and unusual experience that affects us profoundly, and is very difficult to describe.  Also, there are many who think they have seen a total eclipse, when in fact they have only seen a partial eclipse.  They then think it is something that is boring, and of no interest.

The total solar eclipse is a very unique experience.  Those who do experience totality for the first time are often overwhelmed and can’t wait to see it again.

 

https://www.beingintheshadow.com

Here is part of a great description:

Quote

As partiality deepens, and the sliver of Sun shrinks even more, the sky gets darker - very slowly, but noticeably darker. You don't really see it happening, but you can tell it's changing somehow. The shadows on the ground become very sharp, very contrasty, and you feel like there's something wrong with your eyes. At this point, some veteran eclipsers will put an eye patch over one of their eyes, to get it dark-adapted so they can see more detail in the corona during the upcoming totality. Some people don't like that idea, because they like to use both eyes to see totality, and besides, wearing sunglasses during this darkening period probably gets your pupils as open as they're gonna get. But many people do it, so there must be something to it. We wouldn't recommend you do it if this is your first eclipse.

The wind picks up a bit, and the temperature drops noticeably. Birds roost, evening insects come out, and the world prepares for sunset in the middle of the day....

Onset of Totality
Partiality deepens even more, and the atmosphere actually starts to be a little scary. The sky gets deeper and deeper dark blue, and the Sun-sliver gets thin enough that you can actually (through your filters, remember?) start to see it shrinking as you watch it. In the five minutes before totality, you can really get a feel for how earth-shatteringly frightening this event must have been to ancient people who had no idea what was going on. We can truly believe that people could have been frightened to death! But not us - the spectacle gets your heart beating fast, your mouth watering for more, and your whole body trembling with excitement that you're being swept along in a wonderful dance of the cosmos that nothing is going to stop. But we're all too "modern" to allow anything like this to affect us...emotionally, right? Don't you believe it!

As the last bite of the Sun slides away, things happen way too fast to describe concisely. You simply cannot focus on every one of the events that are taking place all around you, so you have to pick the few that seem the coolest to you. (There will be more eclipses, after all, and in about 5 minutes you're going to be on the phone making travel plans to see the next one!) The most important thing going on is the actual Sun up in the sky, but let's take a peek at just a couple of other things first.

The sky surrounding the Sun will grow very dark very quickly. In real time, you will be able to see the deep blue turn to twilight blue, and then to bluish-black. Stars and planets will pop out of nowhere. Roosters will crow and insects will chirp as though night is falling. If you look to the west, you'll see a beautiful black curtain rising up out of the Earth, with hints of sunset-orange north and south of it, while off to the east, the sky at the horizon is still rather light. On the ground, your shadow will become impossibly clear and thin, and then will vanish completely as the Sun's light fades to about the intensity of the full Moon. In the last few seconds before totality, that dull blackness you saw off to the west will suddenly spring up out of the Earth, and take over the whole sky like a gigantic curtain being pulled over you - like that scene in the original Disney Fantasia movie - only about a hundred times faster. If you aren't focused on the Sun at that time (like most people will be), you'll be looking at the actual shadow of the Moon racing toward you at supersonic speed, covering you with its blackness. If you see that, you're very lucky, because it happens so fast. And besides, you'll probably be too awe-struck by what's going on center stage...

As the last sliver of Sun melts away, you will be able to see several things happening simultaneously. You will now definitely have the feeling that there are two bodies involved, because it is impossible to miss the disk of the Moon in these last seconds. (You should still be watching through the eclipse glasses, by the way.) But while the last bit of the sliver is shrinking, the Sun's corona will start to come out. The last little bit of the Sun's light will glare through valleys on the Moon, and will create a "bead" effect at the edge of the Moon's disk. These are called "Baily's Beads", and they are stunning. These will dance around a little, and then will fade away as the very last one of them brightens into a huge bead. Around the edge of the Moon, the Sun's corona will begin to glow, giving us the famous "diamond ring" effect. It lasts for only about 2-3 seconds, but it is stunning beyond words. Most people will take their filters off at this point (though technically, you're not supposed to look until the diamond ring is totally gone, we're just saying that most people choose to do it anyway). You will see the corona burst into view as the diamond fades away, appearing as though someone is smearing wispy-white cotton candy all around the impossibly black hole that's been cut out of the fabric of the blue-black sky. (We are convinced that the corona comes out while the diamond is still blazing away, and it is a beautiful sight to see.) There may be tongues of red fire visible around the edge of the Sun - these are solar prominences, and no one knows what they will look like until they see them right along with you.

...

http://www.eclipse2017.org/2017/what_you_see.htm

[John Cuthber]

9 hours ago, Sensei said:

Take two polarization filters, overlap them together, and rotate one to adjust amount of light which is passing through them.

That trick works well for visible light, but lets the IR through so it's not safe.

[swansont]

9 hours ago, Sensei said:

Take two polarization filters, overlap them together, and rotate one to adjust amount of light which is passing through them.

That's a bad idea. You can easily let too much light pass through.

[Sensei]

4 minutes ago, swansont said:

That's a bad idea. You can easily let too much light pass through.

From 1370 W/m^2 to Earth surface arrive 1050 W/m^2.

It's 0.1050 W/cm^2 while watching Sun directly at noon.

After adding single polarization filter it's 50% 0.0525 W/cm^2 straight away.

After adding second polarization filter and rotate it 90 degrees, you adjust from 0 W/cm^2 to 0.0525 W/cm^2..

With glasses you have absolute no control over it. Even worse, you can't even calculate how much W/cm^2 you will get.

 

[swansont]

Just now, Sensei said:

From 1370 W/m^2 to Earth surface arrive 1050 W/m^2.

It's 0.1050 W/cm^2 while watching Sun directly at noon.

After adding single polarization filter it's 50% 0.0525 W/cm^2 straight away.

After adding second polarization filter and rotate it 90 degrees, you adjust from 0 W/cm^2 to 0.0525 W/cm^2..

Polarizers are not perfect, and if you slip, the angle changes.

Similar to lasers, the light that hits the eye is well-collimated and is focused so the intensity increase by ~5 orders of magnitude by the time it hits the retina. And you pupil does not tend to contract during an eclipse, because the ambient light levels are significantly diminished. 100 mW/cm^2 becomes 10 kW/cm^2 on the retina.

Looking into a 100 mW laser, even from a few meters away (so it's a 1 cm^2 spot) is not something I'd recommend. 

http://ehs.oregonstate.edu/laser/training/laser-biological-hazards-eyes

Quote

With glasses you have absolute no control over it. Even worse, you can't even calculate how much W/cm^2 you will get.

You have control over what glasses you buy. And of course you can calculate the transmission. The optical density tells you exactly that. Optical Density of 5 means 5 orders of magnitude reduction, which is the minimum recommended for the visible (OD ~3 for the NIR)

[iNow]

13 hours ago, zapatos said:

I forgot you were in Iowa. You used to live in Texas, right? 

Exactly. Also, my wife is usually pretty down with this sort of thing. She wouldn't normally need convincing. It's mostly just that we're in new infant territory right now so even "simple" trips to the grocery store require us to put on our war paint and work up the courage for the ride ahead. I'm making progress, though.

Edited August 5, 2017 by iNow

[John Cuthber]

4 hours ago, Sensei said:

 

With glasses you have absolute no control over it. Even worse, you can't even calculate how much W/cm^2 you will get.

 

For a start, why would you want to calculate the power density at the eye?

Since the polarisers don't work properly with IR the calculation you gave may be dangerously wrong.

It's not easy to calculate the fraction of the light that gets through 2 polarisers- again they are not perfect so the cos² theta or whatever isn't correct.

I can calculate the fraction of light that gets through a filter- if I'm given the transmission curve and I wouldn't rely on a filter unless I had that curve.
 

I can measure the transmission if I really want to.

Why not just admit that your idea is dangerously wrong in this case (albeit that it's a useful trick in some other  situations)

[imatfaal]

2 hours ago, iNow said:

Exactly. Also, my wife is usually pretty down with this sort of thing. She wouldn't normally need convincing. It's mostly just that we're in new infant territory right now so even "simple" trips to the grocery store require us to put on our war paint and work up the courage for the ride ahead. I'm making progress, though.

It is the fodder of life long memories - who wants kids to remember the trip to disneyland when they could have great memories of the trip to see the sun go dark

To be honest I think the idea of packing up the station wagon and heading of to see the total eclipse of the sun with wife, curious 4 year-old, and 8-week babe in arms (congrats to you and la iNow btw) sounds like the beginning of a Great American Novel.  And as if to prove my point: I reached up to grab the nearest John Irving I could find - the first chapter is called The Inadequate Lamp Shade (clearly a reference to the eclipse) and the first line is "One night when she was four and sleeping..."   (Admittedly it goes a bit dark from then on in). 

A bibliomancy for the 21st century - do things if they might make a good plot for a novel

 

[iNow]

Thanks for the kind thoughts. I should probably change my username to i-don't_sleep-Now. 

I'm struck by the romantic notions of the trip. I'm confident we'll go, too. 

Whether our novel is love story or horror story / Americana or just plain drama remains to be seen. 

[iNow]

So, we're confirmed. Going to be in the centerline. Fingers crossed the skies are clear. 

 

Edited August 12, 2017 by iNow

[iNow]

They're calling for a strong afternoon thunderstorm Monday. That would suck hard. 

[MigL]

Reminds me of a science fiction story about a planet orbiting multiple suns, such that the sky was always bright.
But every thousand years solar eclipses would bring nightfall, everybody went nuts, and civilization would come to an end.

Be wary of people acting strange.
It could be the beginning of the end.

[Manticore]

1 hour ago, MigL said:

Reminds me of a science fiction story about a planet orbiting multiple suns, such that the sky was always bright.
But every thousand years solar eclipses would bring nightfall, everybody went nuts, and civilization would come to an end.

Be wary of people acting strange.
It could be the beginning of the end.

I remember that one too. Now I'm going to go crazy all day trying to remember who wrote it.