APOD: Ash and Lightning above an Icelandic... (2014 Apr 20)

Comments and questions about the APOD on the main view screen.

APOD: Ash and Lightning above an Icelandic... (2014 Apr 20)

Postby APOD Robot » Sun Apr 20, 2014 4:12 am

Image Ash and Lightning above an Icelandic Volcano

Explanation: Why did a picturesque 2010 volcanic eruption in Iceland create so much ash? Although the large ash plume was not unparalleled in its abundance, its location was particularly noticeable because it drifted across such well-populated areas. The Eyjafjallajökull volcano in southern Iceland began erupting on 2010 March 20, with a second eruption starting under the center of a small glacier on 2010 April 14. Neither eruption was unusually powerful. The second eruption, however, melted a large amount of glacial ice which then cooled and fragmented lava into gritty glass particles that were carried up with the rising volcanic plume. Pictured above during the second eruption, lightning bolts illuminate ash pouring out of the Eyjafjallajökull volcano.

<< Previous APOD This Day in APOD Next APOD >>
User avatar
APOD Robot
Otto Posterman
 
Posts: 1875
Joined: Fri Dec 04, 2009 3:27 am

Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr

Postby LocalColor » Sun Apr 20, 2014 4:59 pm

The "wow factor" is off the scale with this image!
User avatar
LocalColor
Science Officer
 
Posts: 227
Joined: Sat Mar 31, 2012 9:11 pm
Location: Central Idaho, USA

Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr

Postby Jim Leff » Sun Apr 20, 2014 5:18 pm

Great shot. Can anyone explain why the stars in the background have trails?
Jim Leff
Ensign
 
Posts: 65
Joined: Thu Dec 09, 2010 2:00 pm

Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr

Postby BDanielMayfield » Sun Apr 20, 2014 6:20 pm

Jim Leff wrote:Great shot. Can anyone explain why the stars in the background have trails?

Yes, it really is a great shot.

To catch that much lightning a photographer would need an extended exposure time. The stars have trails because the Earth rotates.
"Happy are the peaceable ... "
BDanielMayfield
Don't bring me down
 
Posts: 851
Joined: Thu Aug 02, 2012 11:24 am
Location: South Texas
AKA: Bruce

Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr

Postby Jim Leff » Mon Apr 21, 2014 12:37 am

Then how are the ash plumes so clear and non-blurred?
Jim Leff
Ensign
 
Posts: 65
Joined: Thu Dec 09, 2010 2:00 pm

Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr

Postby geckzilla » Mon Apr 21, 2014 1:04 am

Jim Leff wrote:Then how are the ash plumes so clear and non-blurred?

They were only briefly illuminated by the lightning.
Just call me "geck" because "zilla" is like a last name.
User avatar
geckzilla
Ocular Digitator
 
Posts: 5922
Joined: Wed Sep 12, 2007 12:42 pm
Location: Fresh Meadows, NY

Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr

Postby BDanielMayfield » Mon Apr 21, 2014 1:17 am

Jim Leff wrote:Then how are the ash plumes so clear and non-blurred?


There is some blurring of the ash, which is most noticeable on the right edge of the plume against the blue sky. The exposure time couldn't have been very long, or the star trails would have been longer. There are some APOD commenters that can estimate exposure times from the length of star trails, but I'm not one of them. Maybe someone else can tell us how long this exposure was.
"Happy are the peaceable ... "
BDanielMayfield
Don't bring me down
 
Posts: 851
Joined: Thu Aug 02, 2012 11:24 am
Location: South Texas
AKA: Bruce

Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr

Postby Nitpicker » Mon Apr 21, 2014 2:28 am

The EXIF data suggests a 15 second exposure with a 120mm focal length at f/5.6.

A mesmerising image.
User avatar
Nitpicker
Inverse Square
 
Posts: 1534
Joined: Fri Sep 20, 2013 2:39 am
Location: S27 E153

Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr

Postby Anthony Barreiro » Mon Apr 21, 2014 3:26 am

Awesome elemental energy. A very moving image, but I'm glad I wasn't standing there when the picture was taken.
May all beings be happy, peaceful, and free.
User avatar
Anthony Barreiro
Turtles all the way down
 
Posts: 793
Joined: Wed May 11, 2011 7:09 pm
Location: San Francisco, California, Turtle Island

Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr

Postby DavidLeodis » Mon Apr 21, 2014 11:56 am

It's a superb photo. It would have been a good choice to have been used as the APOD of March 5 2014 (Ash Wednesday). :wink:
User avatar
DavidLeodis
Perceptatron
 
Posts: 827
Joined: Mon May 01, 2006 1:00 pm

Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr

Postby Anthony Barreiro » Mon Apr 21, 2014 1:31 pm

DavidLeodis wrote:It's a superb photo. It would have been a good choice to have been used as the APOD of March 5 2014 (Ash Wednesday). :wink:

Or Wednesday February 18, 2015, for Western (Catholic and Protestant) churches. February 25 for Orthodox churches. Easter, and therefore Ash Wednesday, will come fairly early next year.
May all beings be happy, peaceful, and free.
User avatar
Anthony Barreiro
Turtles all the way down
 
Posts: 793
Joined: Wed May 11, 2011 7:09 pm
Location: San Francisco, California, Turtle Island

Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr

Postby owlice » Mon Apr 21, 2014 1:38 pm

Let's not continue in this vein, David and Anthony; thanks.
A closed mouth gathers no foot.
User avatar
owlice
Guardian of the Codes
 
Posts: 8097
Joined: Wed Aug 04, 2004 4:18 pm
Location: Washington, DC

Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr

Postby Spif » Mon Apr 21, 2014 3:05 pm

LocalColor wrote:The "wow factor" is off the scale with this image!


Looks so amazing that it seems fake to me. Without inspecting the image carefully with photoshop, my first guess is that this is a composite of several lucky lightning strike shots.

-s
Spif
Ensign
 
Posts: 31
Joined: Fri Jan 11, 2013 4:19 pm

Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr

Postby owlice » Mon Apr 21, 2014 3:39 pm

A closed mouth gathers no foot.
User avatar
owlice
Guardian of the Codes
 
Posts: 8097
Joined: Wed Aug 04, 2004 4:18 pm
Location: Washington, DC


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

Who is online

Users browsing this forum: No registered users and 11 guests