Explanation: Have you ever experienced a total eclipse of the Sun? This time-lapse movie depicts such an eclipse in dramatic detail, seenfromAustralia in 2012. As the video begins, a slight dimming of the Sun and the surrounding Earth is barely perceptible. As the Moon moves to cover nearly the entire Sun, darkness sweeps in from the left -- the fully blocked part of the Sun. At totality, only the bright solar corona extends past the edges of the Moon, and darkness surrounds you. Distant horizons are still bright, though, as they are not in the darkest part of the shadow. At mid-totality the darkness dips to the horizon below the eclipsed Sun, created by the shadow cone -- a corridor of shadow that traces back to the Moon. As the total solar eclipse ends -- usually after a few minutes -- the process reverses and Moon's shadow moves off to the other side. Tomorrow afternoon's total solar eclipse -- visible as at least a partial eclipse over all of North America -- can be experienced at social gatherings, some of which are being organized by local libraries.
Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)
Posted: Sun Aug 20, 2017 5:32 am
by Boomer12k
Ok...very interesting to watch the shadow pass...
WELL... It may just be CLEAR on the 21st here around 10-ish for the eclipse, I hope to get you my own pics and video... we shall see what I can see....
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Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)
Posted: Sun Aug 20, 2017 8:34 am
by De58te
Very interesting video.
ta152ho, what do you define as very cold air? The temp drops just a few degrees standing in the shade of a sunny day. Sure this is darkness covering hundreds of miles, but it only lasts a few minutes. How much colder does entering a very long tunnel get on a bright sunny day? (Assume it is a natural cave tunnel that doesn't have electric lights.)
Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)
Posted: Sun Aug 20, 2017 11:16 am
by orin stepanek
On TV news; they said that the hotels and motels are sold out for the event!
Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)
Posted: Sun Aug 20, 2017 1:25 pm
by Guest
geckzilla wrote:
LirrelJohn wrote:"Install Flash"?
Are you kidding? Even Adobe has denounced Flash as dead software.
Sorry, I thought I had cancelled the original post.
Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)
Posted: Sun Aug 20, 2017 1:36 pm
by heehaw
Something I forgot to include in my post yesterday (I'm not at all a solar scientist): heating of the solar corona by sound waves! It seems to me to be a good story: if you had a microphone just above the solar "surface" you would hear a constant loud roar because of the turbulence of the photosphere - and those sound waves go up, without dissipation (sound waves don't dump energy into the atmosphere, that's why you can hear someone talking far away). But as they go up higher and higher, the density of atmosphere goes down and down - that is not mysterious! - until the roar is moving FASTER than the local speed of sound: at which point the interaction with the atmosphere becomes dissipative: and so a tremendous amount of sound energy is dumped into a very small amount of residual atmosphere, which therefore is heated to a very high temperature.
That sounds good to me, but I am no expert; I'd love to hear expert comment on this.
Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)
Posted: Sun Aug 20, 2017 2:06 pm
by heehaw
Well, I finally googled (which is what I should have done first) and got my answer: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5422629/
Actually, that is more than I bargained for: almost too much! I haven't read it all yet!
Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)
Posted: Sun Aug 20, 2017 5:25 pm
by Chris Peterson
De58te wrote:Very interesting video.
ta152ho, what do you define as very cold air? The temp drops just a few degrees standing in the shade of a sunny day. Sure this is darkness covering hundreds of miles, but it only lasts a few minutes. How much colder does entering a very long tunnel get on a bright sunny day? (Assume it is a natural cave tunnel that doesn't have electric lights.)
It doesn't last a few minutes. It lasts a few hours. All that time with reduced sunlight for hundreds of miles around. The total drop can be tens of degrees by totality in a dry location.
I'm sitting in such a location myself now, on a high ridge in Wyoming, just a few hundred meters from the centerline, taking all my equipment through a dry run. So far, so good. There's a great sunspot group on the Sun's center. Not a soul within a few miles. Just me and the pronghorns and the grasshoppers.
Can't believe I have 3G cellular data here! It's the middle of nowhere.
Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)
Posted: Sun Aug 20, 2017 7:55 pm
by ToucanSam
Chris, I think your luck's gonna hold out!
Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)
Posted: Sun Aug 20, 2017 8:34 pm
by neufer
Click to play embedded YouTube video.
Chris Peterson wrote:
I'm sitting in such a location myself now, on a high ridge in Wyoming, just a few hundred meters from the centerline, taking all my equipment through a dry run. So far, so good. There's a great sunspot group on the Sun's center. Not a soul within a few miles. Just me and the pronghorns and the grasshoppers.
Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)
Posted: Mon Aug 21, 2017 12:46 am
by Chris Peterson
It's Wyoming. The pronghorn are that thick. The grasshoppers, not so much.
Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)
Posted: Mon Aug 21, 2017 7:49 pm
by orin stepanek
Well the eclipse came and went! My dog didn't seem to mind at all! The little Magic didn't pay it any attention! It was thought that some animals might think it was evening time but no mine!
Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)
Posted: Mon Aug 21, 2017 7:52 pm
by neufer
orin stepanek wrote:
Well the eclipse came and went! My dog didn't seem to mind at all! The little Magic didn't pay it any attention! It was thought that some animals might think it was evening time but no mine!
Perhaps little Magic is a little thick.
Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)
Posted: Sat Aug 26, 2017 4:11 am
by alter-ego
Chris Peterson wrote:
De58te wrote:Very interesting video.
ta152ho, what do you define as very cold air? The temp drops just a few degrees standing in the shade of a sunny day. Sure this is darkness covering hundreds of miles, but it only lasts a few minutes. How much colder does entering a very long tunnel get on a bright sunny day? (Assume it is a natural cave tunnel that doesn't have electric lights.)
It doesn't last a few minutes. It lasts a few hours. All that time with reduced sunlight for hundreds of miles around. The total drop can be tens of degrees by totality in a dry location.
...
I could feel an air temp drop early on in the eclipse. Below is the measured temperature drop throughout the entire eclipse in Glendo, WY.
Time-Lapse: A Total Solar Eclipse