by APOD Robot » Mon Mar 21, 2016 4:08 am
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.
[/b]
[url=http://apod.nasa.gov/apod/ap160321.html][img]http://apod.nasa.gov/apod/calendar/S_160321.jpg[/img] [size=150]Alaskan Moondogs[/size][/url]
[b] Explanation: [/b] What's happened to the sky? Moonlight illuminates a snowy scene in [url=https://www.facebook.com/photo.php?fbid=554534044559189&set=a.312646138747982.88420.312643312081598&type=1&theater]this night land and skyscape[/url] made on 2013 January from Lower Miller Creek, [url=https://en.wikipedia.org/wiki/Alaska]Alaska[/url], [url=https://en.wikipedia.org/wiki/United_States]USA[/url]. Overexposed near the mountainous western horizon is the first quarter Moon itself, surrounded by an [url=http://apod.nasa.gov/apod/ap121203.html]icy halo[/url] and flanked left and right [url=http://www.atoptics.co.uk/halo/parmoon.htm]by moondogs[/url]. Sometimes called mock moons, a more scientific name for the luminous apparitions is paraselenae (plural). [url=http://apod.nasa.gov/apod/ap110110.html]Analogous to[/url] a sundog or parhelion, a paraselene is produced by moonlight refracted through thin, hexagonal, plate-shaped ice crystals in high [url=http://earthobservatory.nasa.gov/IOTD/view.php?id=85943]cirrus clouds[/url]. As determined by [url=http://www.atoptics.co.uk/halo/dogfm.htm]the crystal geometry[/url], paraselenae are seen at an angle of 22 degrees or more from the Moon. Compared to the bright lunar disk, [url=http://apod.nasa.gov/apod/ap090611.html]paraselenae are faint[/url] and easier to spot when the Moon is low.
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