APOD: Alaskan Moondogs (2016 Mar 21)

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APOD: Alaskan Moondogs (2016 Mar 21)

Post by APOD Robot » Mon Mar 21, 2016 4:08 am

Image Alaskan Moondogs

Explanation: What's happened to the sky? Moonlight illuminates a snowy scene in this night land and skyscape made on 2013 January from Lower Miller Creek, Alaska, USA. Overexposed near the mountainous western horizon is the first quarter Moon itself, surrounded by an icy halo and flanked left and right by moondogs. Sometimes called mock moons, a more scientific name for the luminous apparitions is paraselenae (plural). Analogous to a sundog or parhelion, a paraselene is produced by moonlight refracted through thin, hexagonal, plate-shaped ice crystals in high cirrus clouds. As determined by the crystal geometry, paraselenae are seen at an angle of 22 degrees or more from the Moon. Compared to the bright lunar disk, paraselenae are faint and easier to spot when the Moon is low.

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Re: APOD: Alaskan Moondogs (2016 Mar 21)

Post by Beyond » Mon Mar 21, 2016 4:16 am

Finally! Something to howl at the earth, for a change.
To find the Truth, you must go Beyond.

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Re: APOD: Alaskan Moondogs (2016 Mar 21)

Post by Boomer12k » Mon Mar 21, 2016 8:13 am

Really nice shot...

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Re: APOD: Alaskan Moondogs (2016 Mar 21)

Post by heehaw » Mon Mar 21, 2016 8:45 am

What's happened to the Earth? Look at those glints on the snow!

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Re: APOD: Alaskan Moondogs (2016 Mar 21)

Post by RJN » Mon Mar 21, 2016 2:47 pm

I deleted the reference to cirrus clouds in the NASA APOD text since there are likely few cirrus clouds between the observer and the mountain. I apologize for the oversight. - RJN

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Re: APOD: Alaskan Moondogs (2016 Mar 21)

Post by starsurfer » Mon Mar 21, 2016 2:50 pm

This is very nice, I have seen sundogs but never moondogs. I think Moonlady will like this one. :)