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APOD: Ash and Lightning above an Icelandic... (2014 Apr 20)
Posted: Sun Apr 20, 2014 4:12 am
by APOD Robot
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.
[/b]
Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr
Posted: Sun Apr 20, 2014 4:59 pm
by LocalColor
The "wow factor" is off the scale with this image!
Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr
Posted: Sun Apr 20, 2014 5:18 pm
by Jim Leff
Great shot. Can anyone explain why the stars in the background have trails?
Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr
Posted: Sun Apr 20, 2014 6:20 pm
by BDanielMayfield
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.
Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr
Posted: Mon Apr 21, 2014 12:37 am
by Jim Leff
Then how are the ash plumes so clear and non-blurred?
Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr
Posted: Mon Apr 21, 2014 1:04 am
by geckzilla
Jim Leff wrote:Then how are the ash plumes so clear and non-blurred?
They were only briefly illuminated by the lightning.
Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr
Posted: Mon Apr 21, 2014 1:17 am
by BDanielMayfield
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.
Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr
Posted: Mon Apr 21, 2014 2:28 am
by Nitpicker
The EXIF data suggests a 15 second exposure with a 120mm focal length at f/5.6.
A mesmerising image.
Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr
Posted: Mon Apr 21, 2014 3:26 am
by Anthony Barreiro
Awesome elemental energy. A very moving image, but I'm glad I wasn't standing there when the picture was taken.
Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr
Posted: Mon Apr 21, 2014 11:56 am
by DavidLeodis
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 :wink:](./images/smilies/icon_wink.gif)
Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr
Posted: Mon Apr 21, 2014 1:31 pm
by Anthony Barreiro
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 :wink:](./images/smilies/icon_wink.gif)
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.
Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr
Posted: Mon Apr 21, 2014 1:38 pm
by owlice
Let's not continue in this vein, David and Anthony; thanks.
Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr
Posted: Mon Apr 21, 2014 3:05 pm
by Spif
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
Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr
Posted: Mon Apr 21, 2014 3:39 pm
by owlice