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

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

Post by 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.

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

Post by LocalColor » Sun Apr 20, 2014 4:59 pm

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

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

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

Great shot. Can anyone explain why the stars in the background have trails?

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

Post by 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.
Just as zero is not equal to infinity, everything coming from nothing is illogical.

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

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

Then how are the ash plumes so clear and non-blurred?

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

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

Post by 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.
Just as zero is not equal to infinity, everything coming from nothing is illogical.

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

Post by 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.

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

Post by 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.

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

Post by 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:

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

Post by 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.

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

Post by owlice » Mon Apr 21, 2014 1:38 pm

Let's not continue in this vein, David and Anthony; thanks.
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Re: APOD: Ash and Lightning above an Icelandic... (2014 Apr

Post by 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

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

Post by owlice » Mon Apr 21, 2014 3:39 pm

A closed mouth gathers no foot.

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