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APOD: Moondog Night (2014 Dec 11)

Posted: Thu Dec 11, 2014 5:08 am
by APOD Robot
Image Moondog Night

Explanation: In this night scene from the early hours of November 14, light from a last quarter Moon illuminates clouds above the mountaintop domes of Kitt Peak National Observatory near Tucson, Arizona. Bright Jupiter is just left of the overexposed lunar disk with a streak of camera lens flare immediately to the right, but that's no fireball meteor exploding near the center of the picture. Instead, from the roadside perspective a stunningly bright moondog or paraselene stands directly over Kitt Peaks's WIYN telescope. 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 (plural) are seen at an angle of 22 degrees or more from the Moon. Compared to the bright lunar disk they are more often faint and easier to spot when the Moon is low. About 10 minutes after the photograph even this bright moondog had faded from the night.

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Re: APOD: Moondog Night (2014 Dec 11)

Posted: Thu Dec 11, 2014 7:57 am
by Postman
And then there is the second arc at 44 degrees on the left.

Re: APOD: Moondog Night (2014 Dec 11)

Posted: Thu Dec 11, 2014 8:36 am
by madtom1999
Postman - I'm guessing that is a camera internal reflection thing but then again....

Re: APOD: Moondog Night (2014 Dec 11)

Posted: Thu Dec 11, 2014 9:33 am
by MikeH
What is the technical name for Sundogs, ie the same reflections in daylight?

I remember seeing the Sun with two mini suns on each side many years back in the Scottish Borders. They must be far more common in higher latitiudes.

Re: APOD: Moondog Night (2014 Dec 11)

Posted: Thu Dec 11, 2014 9:47 am
by Boomer12k
Awesome lookin'....
It was clear when I went out earlier, and the Moon was bright, and Orion was looked great.

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Re: APOD: Moondog Night (2014 Dec 11)

Posted: Thu Dec 11, 2014 11:33 am
by geckzilla
MikeH wrote:What is the technical name for Sundogs, ie the same reflections in daylight?
Parhelia. I suppose the lunar equivalent is parselenia.

Re: APOD: Moondog Night (2014 Dec 11)

Posted: Thu Dec 11, 2014 2:40 pm
by Chris Peterson
MikeH wrote:I remember seeing the Sun with two mini suns on each side many years back in the Scottish Borders. They must be far more common in higher latitiudes.
Maybe a little, because ice clouds might be a little more common. But sundogs and moondogs are extremely common nearly everywhere. I see them dozens of time each year, from 38°N.

Re: APOD: Moondog Night (2014 Dec 11)

Posted: Thu Dec 11, 2014 3:20 pm
by FloridaMike
How common are they at 28°N ?

Re: APOD: Moondog Night (2014 Dec 11)

Posted: Thu Dec 11, 2014 3:29 pm
by Chris Peterson
FloridaMike wrote:How common are they at 28°N ?
I'd say they're extremely common- many per year at any latitude, since thin ice clouds are common from the poles to the equator.

Re: APOD: Moondog Night (2014 Dec 11)

Posted: Thu Dec 11, 2014 3:35 pm
by Pmmcafee
We had a great early morning moon and, later on, a sun halo here in LA this last Sunday!

Re: APOD: Moondog Night (2014 Dec 11)

Posted: Thu Dec 11, 2014 5:55 pm
by BMAONE23
Postman wrote:And then there is the second arc at 44 degrees on the left.
madtom1999 wrote:Postman - I'm guessing that is a camera internal reflection thing but then again....
It is definitely more than a flare. It is a multicolored arc at 44 deg (extreme 9:00) just like a Colored Rainbow

Re: APOD: Moondog Night (2014 Dec 11)

Posted: Fri Dec 12, 2014 12:19 am
by Nitpicker
BMAONE23 wrote:
Postman wrote:And then there is the second arc at 44 degrees on the left.
madtom1999 wrote:Postman - I'm guessing that is a camera internal reflection thing but then again....
It is definitely more than a flare. It is a multicolored arc at 44 deg (extreme 9:00) just like a Colored Rainbow
Rainbow-like lens flares are quite common.

Re: APOD: Moondog Night (2014 Dec 11)

Posted: Fri Dec 12, 2014 1:27 am
by Chris Peterson
BMAONE23 wrote:
Postman wrote:And then there is the second arc at 44 degrees on the left.
madtom1999 wrote:Postman - I'm guessing that is a camera internal reflection thing but then again....
It is definitely more than a flare. It is a multicolored arc at 44 deg (extreme 9:00) just like a Colored Rainbow
I think it's flare. If it were a halo, it would almost have to be a fragment of the very rare 46° halo, and the colors are too saturated and run in the wrong direction for that.

Re: APOD: Moondog Night (2014 Dec 11)

Posted: Fri Dec 12, 2014 1:53 am
by BMAONE23
The colors are reversed aren't they, Blue hues toward the source instead of red