Total Solar Eclipse 2017

16 Jun 2017 13:55

It's always a risk. But the chances that you'll see it if you're not in the totality path is 0%.

And even in the unfortunate event that it is cloudy, the totality is still dramatic:

[youtube]2CsK5psgiZg[/youtube]

16 Jun 2017 14:00

Watsisname, yeah, so where are you going to see the Eclipse? I'm going to Lincoln, NE (I have family there)

16 Jun 2017 14:16

Lincoln's good, but get the family to drive closer to the centerline if you can.

Driving just 30 miles south will gain you more than an extra minute of totality, and every second of totality is precious.

I'll be near Madras Oregon.

16 Jun 2017 15:00

Watsisname, advice taken. Have you ever witnessed a solar eclipse before?

midtskogen · 16 Jun 2017 15:49

If it's cloudy (and not too cloudy or low clouds), look for the Moon's shadow race across the sky. It's not as good as a perfectly clear sky, but I've seen both kinds of totalities.

The extra minute is definitely worth a short drive (or even a long hike). Not just for the extra minute, but for the light and symmetry. Remember that areas outside the totality are visible near the horizon throughout the totality. But again, better to be in the edge of the totality zone with a visible sun than to be in the centre with no sun.

16 Jun 2017 17:04

Have you ever witnessed a solar eclipse before?

Only partials, so in other words not truly. Deepest I've seen so far was 80% coverage in 1994. I was in elementary school, and an annular eclipse passed a few states to the north. I distinctly remember the sky being a darker shade of blue than normal. It felt more like late evening than midday. The teachers brought us out with eclipse glasses and we saw the brilliant crescent Sun in the sky.

It was pretty neat and memorable, but still just a partial. I would even say a total lunar eclipse is much more interesting than a deep partial solar. Totality will be something very new.

midtskogen · 17 Jun 2017 01:17

A fairly deep partial solar eclipse will give a pale light and shadows will sharpen. It's something slightly unreal about it. If it reaches 99%, you can see shadow lines or bands on bright surfaces, a wave like pattern moving like shadows on a shallow seafloor. That can be a very weird experience. If you're in a snowy landscape and the air turbulence is high, it's like the ground beneath you, or the world itself, begins to be torn apart. The sun flickers in the sky. It's the weirdest thing. Look for the effect during the two minutes before and after totality. You probably need a plain, white surface nearby to see it well, though.

If there is a partial eclipse and overcast, you wont notice a thing, really. It does get darker, but you wouldn't be able to tell that apart from just a thicker cloud layer.

I once saw a partial eclipse of the midnight sun. It's not anything special about that objectively, of course, but I'll have it on my list of eclipses.

It was on 31 July 2000, seen from Ny-Ålesund (79N 12E). It was snowing that night, but the clouds cleared for a while and I got my photo of it.

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midtskogen · 18 Jun 2017 09:43

I'm aiming for Madras somehow (but I haven't been able to book a camping spot, because the ticket system seems currently broken). Now I looked up the weather statistics for Madras and got a bit surprised. So the average high in August is 30C (record: 43C) and that sounds reasonable, but the average low is 6C and the record low is -6C. That sounds quite desert like. It's a good thing to know when packing the right sleeping bag.

18 Jun 2017 19:47

Yeah, east of the mountains is shadow desert, which is good for the cloud statistics, but also means big temperature swings. Be prepared, and have lots of fluids. Heat stroke will be a concern during the day and it will be very chilly at night.

It'll be interesting to see how much the eclipse cools things down that morning (totality around 10:20am local time). Probably even more so further east when it occurs early afternoon. I guess the effect wasn't so strong or felt in Svalbard.

midtskogen · 19 Jun 2017 00:42

I guess the effect wasn't so strong or felt in Svalbard.

Since the diurnal variation there is small and secondary to wind direction/weather, it would be surprising if an eclipse could give an effect of any significance. This study found a weak effect, if any. Near my position there was a weather station run by the university with minute resolution. I checked it after the eclipse, and it was hard to find any clear temperature drop. Perhaps, but much smaller than the random temperature fluctuations during the hours before and after (-19C - -22C or so). I can't find the data now.
Below is a list of observations from various meteorological stations and I think all of them were in the totality zone. They only have data every our reporting temperature at the top of the our and min and max during the previous hour. The totality started 11:10, but if the temperature at 11 was -20.8C and the minimum of the next our was -20.8C as well (or only slightly lower), the effect is practically zero for the totality (but some effect could already have taken by 11:00). In any case, the effect must have been less than random weather fluctuations. In my video the audio suggests that the wind picked up (which is more noticeable in -20C than a few tenths of a degree actual change), but it might be just random weather. Usually, I think one would rather expect the wind to drop during a totality.

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EDIT: I cut and pasted the weather data from tables, and the formatting became bad. I don't know how to fix that,

19 Jun 2017 03:16

That's interesting now that you mention the wind. I've looked at a lot of totality videos, and for the real time ones with audio it often seemed to me that the wind changed in some way during or near totality. I always put it off as random weather, which in your case in Svalbard it probably is. Now I decided to look into it further.

Apparently, the "eclipse wind" is actually a real thing. This is fascinating to me. As you would think it is more often a weakening of the wind with the loss of convection, but more significantly there is a change in the wind direction as well. In fact it was hypothesized back in 1901, using observations from the 1900 eclipse and the early theory of cyclonic systems, that the temperature drop induced by the shadow should act as a cyclonic system, with winds circulating about the center (actually a point just trailing totality, since that's where the minimum temperature is). This pattern is subtle and overlaid on top of whatever the regular weather is already doing, so it's difficult to notice. But it can be seen as a small, systematic change in average wind direction throughout the shadow. Furthermore, while the air itself does not move with the shadow (that of course would be absurd at thousands of km per hour), the pattern does, like a wave through the atmosphere.

I love this section of the 1901 paper:

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This was investigated in much more detail in recent eclipses, using comparison of observations to models with and without the eclipse, and they substantiate this "eclipse cyclone" theory. This year should be an outstanding opportunity to test it further with such a long track over populated land.

An excellent dissertation about the meteorological effects of eclipses, including the eclipse wind.

On an unrelated note I wanted to ask, if you remember, how early before totality did Venus appear (or how long could it still be seen after?) I suppose it varies a lot from one eclipse to another, but 2015 and 2017 are pretty similar in terms of the magnitude of both the eclipse and Venus.

YouTube · 19 Jun 2017 06:25

Blue Hill

I have been there many times, I grew up within sight of it

First permanent meteorological observatory in the USA, if I recall correctly.

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midtskogen · 19 Jun 2017 07:22

On an unrelated note I wanted to ask, if you remember, how early before totality did Venus appear (or how long could it still be seen after?)

It's hard to say two years after, but I do remember that it was visible a while before the totality, but whether a while is 15 minutes or 30 minutes I can't tell anymore. Also, when I first spotted Venus, it was clearly visible. The visibility is easier to time after the totality, since you then know where to look. I didn't look for it after the eclipse.

08 Jul 2017 22:30

Added some maps and further information to the OP. 43 days to go -- a lunar cycle and a half.

YouTube · 09 Jul 2017 01:25

Naturally I will be going to the cloudiest location possible

On the bright side, I recently got a solar filter for my camera, so if it's not cloudy I should get some nice shots!

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