APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 2995
Joined: Fri Dec 04, 2009 3:27 am

APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)

Postby APOD Robot » Sun Aug 20, 2017 4:06 am

Image Time-Lapse: A Total Solar Eclipse

Explanation: Have you ever experienced a total eclipse of the Sun? This time-lapse movie depicts such an eclipse in dramatic detail, seen from Australia 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.

<< Previous APOD This Day in APOD Next APOD >>

ta152h0
Schooled
Posts: 1261
Joined: Mon Aug 29, 2005 12:46 am
Location: Auburn, Washington, USA

Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)

Postby ta152h0 » Sun Aug 20, 2017 4:12 am

Add a immediate blast of very cold air.......
Wolf Kotenberg

LirrelJohn
Ensign
Posts: 15
Joined: Tue Feb 14, 2017 10:50 pm

Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)

Postby LirrelJohn » Sun Aug 20, 2017 4:14 am

"Install Flash"?

Are you kidding? Even Adobe has denounced Flash as dead software.

User avatar
geckzilla
Ocular Digitator
Posts: 8640
Joined: Wed Sep 12, 2007 12:42 pm
Location: Modesto, CA

Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)

Postby geckzilla » Sun Aug 20, 2017 4:59 am

LirrelJohn wrote:"Install Flash"?

Are you kidding? Even Adobe has denounced Flash as dead software.

Maybe an HTML5 version will play at the website. https://vimeo.com/53641212
Just call me "geck" because "zilla" is like a last name.

Boomer12k
:---[===] *
Posts: 2089
Joined: Sun Apr 22, 2007 12:07 am

Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)

Postby Boomer12k » Sun Aug 20, 2017 5:32 am

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....

:---[===]

De58te
Ensign
Posts: 88
Joined: Mon Sep 30, 2013 6:35 pm

Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)

Postby De58te » Sun Aug 20, 2017 8:34 am

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.)

User avatar
orin stepanek
Plutopian
Posts: 4469
Joined: Wed Jul 27, 2005 3:41 pm
Location: Nebraska

Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)

Postby orin stepanek » Sun Aug 20, 2017 11:16 am

On TV news; they said that the hotels and motels are sold out for the event!
Orin

Smile today; tomorrow's another day!

Guest

Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)

Postby Guest » Sun Aug 20, 2017 1:25 pm

geckzilla wrote:
LirrelJohn wrote:"Install Flash"?

Are you kidding? Even Adobe has denounced Flash as dead software.

Maybe an HTML5 version will play at the website. https://vimeo.com/53641212


It did, thank you. It's quite pretty.


Sorry, I thought I had cancelled the original post.

heehaw

Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)

Postby heehaw » Sun Aug 20, 2017 1:36 pm

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.

heehaw

Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)

Postby heehaw » Sun Aug 20, 2017 2:06 pm

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!

User avatar
Chris Peterson
Abominable Snowman
Posts: 13273
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)

Postby Chris Peterson » Sun Aug 20, 2017 5:25 pm

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.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

ToucanSam
Asternaut
Posts: 1
Joined: Thu Jan 28, 2016 9:45 pm

Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)

Postby ToucanSam » Sun Aug 20, 2017 7:55 pm

Chris, I think your luck's gonna hold out!

User avatar
neufer
Vacationer at Tralfamadore
Posts: 14417
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)

Postby neufer » Sun Aug 20, 2017 8:34 pm

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.
Art Neuendorffer

User avatar
Chris Peterson
Abominable Snowman
Posts: 13273
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)

Postby Chris Peterson » Mon Aug 21, 2017 12:46 am

It's Wyoming. The pronghorn are that thick. The grasshoppers, not so much.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
orin stepanek
Plutopian
Posts: 4469
Joined: Wed Jul 27, 2005 3:41 pm
Location: Nebraska

Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)

Postby orin stepanek » Mon Aug 21, 2017 7:49 pm

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! :lol2:
Orin

Smile today; tomorrow's another day!

User avatar
neufer
Vacationer at Tralfamadore
Posts: 14417
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)

Postby neufer » Mon Aug 21, 2017 7:52 pm

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! :lol2:

Perhaps little Magic is a little thick.
Art Neuendorffer

User avatar
alter-ego
Serendipitous Sleuthhound
Posts: 746
Joined: Mon Apr 21, 2008 4:51 am
Location: Redmond, WA

Re: APOD: Time-Lapse: A Total Solar Eclipse (2017 Aug 20)

Postby alter-ego » Sat Aug 26, 2017 4:11 am

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.

http://www.skyandtelescope.com/astronomy-news/solar-system/experiencing-totality-eclipse-stories-from-sky-telescope/

Temperature Drop in Glendo, WY.JPG
You do not have the required permissions to view the files attached to this post.
A pessimist is nothing more than an experienced optimist


Return to “The Bridge: Discuss an Astronomy Picture of the Day”

Who is online

Users browsing this forum: CommonCrawl [Bot] and 1 guest