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Re:Eclipses and Decibels by idlewords on Monday August 28, 2017 @02:01PM (#15118687)
It's not true that you don't perceive the darkening of the sun until just near totality. Instead, what you get is a really weird subliminal creepy feeling that something is wrong.

You're seeing things with the brightness of a rainy day, and then with the brightness of sunset, but the color balance is that of full sunlight. For me at least it's very unsettling, and I wonder if other people experience it that way.

The uncanny feeling is quite visceral and a big part of the reason I think eclipses just have to be experienced. All kinds of alarms go off in your animal brain when the moon eats the sun.

This is not to take away from the author's very correct observation that the light effects only really kick in close to totality, I'd say with over 90% of the sun covered.

Re:Eclipses and Decibels by ctdonath on Monday August 28, 2017 @02:20PM (#15118840)
Yup, it's a "had to be there" thing. Complete eclipse, start to finish, took 3 hours. Totality was just over 2 minutes. Most of the time, lighting can only be described as "odd" - as you put it, color balance of full sunlight for brightness of sunset. Bugs & animals picked up on it, rapidly heading into night mode. Humans tended to stand around slowly realizing "huh? that's odd". Lighting starts as a sense of just wrong. Then at about 95% totality (!) you finally perceive the rate of change, as it exponentially plunges into darkness. Then you realize the darkness isn't, you're seeing with the visibility of a nightlight (but color balance still that of full sunlight), and proceed to freak over the visibility of the corona surrounding a big, well, black hole where the sun was. The horizon is also oddly bright.

And yes, there's a huge difference between any perceivable percentage away from totality, and totality itself. We're talking fractions of a second making a difference between direct viewing vs rapidly going blind.

Re:Eclipses and Decibels by dredmorbius on Monday August 28, 2017 @03:46PM (#15119476)
NB: The colour-balance of night, say, under a full moon, is actually pretty close to that of daytime.

It's just ... well ... a lot darker.

Shooting long-exposure slide film is a good way to confirm this (no colour adjustment possible).

Moonlight is has a slightly lower (that is, optically "warmer") colour temperature -- 4100K rather than 5000K.

Contrast with "daylight" vs. "tungsten" film colour balance: 5500K vs. 3200K.

https://physics.stackexchange.com/questions/244922/why-does-...

http://www.apogeephoto.com/white-balance-and-color-temperatu...

Re:Eclipses and Decibels by nkrisc on Monday August 28, 2017 @04:02PM (#15119596)
A lot darker, indeed. I recall camping in the mountains near Vail, Colorado many years ago during a full moon. It almost felt like day, but with a black sky. It was quite surreal. My immediate surrounding were illuminated (everything cast a distinct shadow) but everything just beyond your immediate vision was in darkness.
Re:Eclipses and Decibels by Florin_Andrei on Monday August 28, 2017 @08:48PM (#15121359)
> Shooting long-exposure slide film is a good way to confirm this (no colour adjustment possible).

Or shooting long exposure with a digital camera that does not automatically adjust the color balance. E.g. take the raw data from the sensor, instead of a camera-generated JPEG.

Re:Eclipses and Decibels by dredmorbius on Monday August 28, 2017 @10:59PM (#15121809)
Right. I was also contrasting _print_ film (negative process) as virtually all film-development would attemtp to "correct" shots for exposure and colour balance.

(Much of my experimental night photography was conducted ... some time ago.)

Re:Eclipses and Decibels by Florin_Andrei on Tuesday August 29, 2017 @03:03PM (#15126767)
Hey, I did some of that too. Had my own little dark room and everything.

Working with film was, um, exciting? Not sure if that's the right word. Anyway, mistakes were final. I remember deliberating on the settings for a really long time before pushing the button.

Re:Eclipses and Decibels by Florin_Andrei on Monday August 28, 2017 @03:08PM (#15119188)
Color balance does shift a bit towards red when it's close to totality. I've picked it up visually (it's a small change), and the camera also confirms it:

https://www.youtube.com/watch?v=af0dQLdmhxs

Re:Eclipses and Decibels by peeters on Monday August 28, 2017 @08:26PM (#15121249)
Why is it so much warmer immediately after totality than immediately before? Seems more like the camera shifted its white balance over the course of the video.

Thanks for sharing though! I wasn't able to experience the full eclipse so I love seeing others experience it.

Re:Eclipses and Decibels by Florin_Andrei on Monday August 28, 2017 @08:44PM (#15121338)
The camera's white balance definitely did shift.

To my eyes, close to totality (on either side) the light was a bit redshifted. Not much, but a little. The change seemed symmetrical before and after.

I've imaged the whole event. Looking at the disk of the Sun, the color is not the same everywhere. The edge definitely loses energy in the blue end of the spectrum - I believe for the same reason why blue light is dispersed more, compared to red, in Earth's atmosphere. So near totality, when you receive light only from the edge of the photosphere, it's normal that the spectral composition looks different.

Re:Eclipses and Decibels by joezydeco on Monday August 28, 2017 @04:05PM (#15119632)
Thank you for explaining the color balance thing.

We were driving across the totality zone as the partial increased from 30% to about 90%. There was almost no loss of "brightness" per se, but everything had this odd "haze" to it as you looked around without normal driving sunglasses. You knew something was different, but not in style of a sunset or cloud-obscured day.

Re:Eclipses and Decibels by matthewmcg on Monday August 28, 2017 @02:37PM (#15118954)
Not only the "this light is too dim for having daylight color balance" feeling, but the shift of the sun from a disc to a crescent makes shadows and shading look very odd.
Re:Eclipses and Decibels by munificent on Monday August 28, 2017 @03:57PM (#15119560)
> You're seeing things with the brightness of a rainy day, and then with the brightness of sunset, but the color balance is that of full sunlight.

Also, it has the brightness of an overcast day, but the shadows are still sharp-edged, just dim.

Re:Eclipses and Decibels by maxxxxx on Monday August 28, 2017 @03:20PM (#15119271)
The thing I noticed earliest was that it got colder. An hour before the eclipse everybody wore a T-shirt. 10 minutes before we all wore a jacket.

As far as light goes I would compare it to a full moon. We are not used to having dim light come from above. We are only used to it coming from the horizon at sunrise or sunset. That's why the light felt "wrong"/

Re:Eclipses and Decibels by LTG on Monday August 28, 2017 @02:48PM (#15119035)
For me, it felt like my "animal brain" decided something must be wrong with my eyes: I started rubbing them, as though I had just come indoors after a bright day.

I took my (corrective) glasses off, and then felt confused when everything got blurry. Some part of my brain must have thought they were sunglasses.

I swear I could feel myself get more anxious when taking my glasses off didn't "fix the problem" - like the "animal brain" could remain calm as long as the dim light could be explained by something familiar.

Re:Eclipses and Decibels by boondaburrah on Monday August 28, 2017 @06:39PM (#15120733)
I wasn't within the region that would have totality. What I got mostly was this (partial was somewhere around 60-70 percent):

  Me:    Walks outside (currently not cloudy).
  Brain: "Tut tut, looks like rai-WAIT WHY ARE THERE HARD SHADOWS?"
This happens to me whenever I wear sunglasses (my brain does not like them), but the weirdest feeling was not being able to feel glasses on my face because this time there weren't any!
Re:Eclipses and Decibels by trentmb on Monday August 28, 2017 @04:03PM (#15119610)
Man, I had such a different experience viewing the eclipse.

It was kinda cool, but

> Instead, what you get is a really weird subliminal creepy feeling that something is wrong.

and

> The uncanny feeling is quite visceral and a big part of the reason I think eclipses just have to be experienced. All kinds of alarms go off in your animal brain when the moon eats the sun.

simply do not resonate with me.

Re:Eclipses and Decibels by grzm on Monday August 28, 2017 @02:04PM (#15118713)
I concur with the "creepy" feeling. I wasn't in the path to experience the full eclipse and it was slightly overcast, and wasn't even aware of the exact time of peak occlusion where I was. However, I still noticed that something wasn't quite right. Noticeably peculiar.
Re:Eclipses and Decibels by slavik81 on Tuesday August 29, 2017 @02:38AM (#15122538)
It didn't really seem that odd to me. We had 75% coverage and it was more or less as if a cloud was passing by. Had I not known there was an eclipse that day, I might not have even noticed it wasn't.