APOD: A Quadruple Lunar Halo Over Spain (2012 Dec 03)

Comments and questions about the APOD on the main view screen.

Have you ever seen a lunar halo?

Poll ended at Sun Dec 09, 2012 5:05 am

Yes
1344
88%
No
165
11%
What's a lunar halo?
27
2%
 
Total votes: 1536

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Chris Peterson
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Re: APOD: A Quadruple Lunar Halo Over Spain (2012 Dec 03)

Post by Chris Peterson » Mon Dec 03, 2012 5:41 pm

florid_snow wrote:Getting corrected by Chris is like a dream come true, I always appreciate reading your clear comments on here.
Thanks... but you made me spit my coffee onto my keyboard when I saw that! (A perfect storm- your comment and I was listening to Tim Minchin at the same time.)
Chris

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orin stepanek
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Re: APOD: A Quadruple Lunar Halo Over Spain (2012 Dec 03)

Post by orin stepanek » Mon Dec 03, 2012 5:51 pm

Interesting photo; but was the fish-eye lens necessary to capture the view? I think it could be a beautiful photo if done with regular photography! Just MHO!
Orin

Smile today; tomorrow's another day!

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Chris Peterson
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Re: APOD: A Quadruple Lunar Halo Over Spain (2012 Dec 03)

Post by Chris Peterson » Mon Dec 03, 2012 6:09 pm

orin stepanek wrote:Interesting photo; but was the fish-eye lens necessary to capture the view? I think it could be a beautiful photo if done with regular photography! Just MHO!
A 46° halo is specified by its radius. In other words, just capturing it completely (which this image does not) requires a vertical field of view of 92°, which (given typical image aspect ratios) means a horizontal FOV of 140°. That requires what is commonly called an ultra wide angle lens, which is probably what was used for this image (not a fisheye).
Chris

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JohnD
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Re: APOD: A Quadruple Lunar Halo Over Spain (2012 Dec 03)

Post by JohnD » Mon Dec 03, 2012 6:58 pm

http://www.atoptics.co.uk/fz472.htm

That is more explanatory!
Thnaks, furry snow!
John

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orin stepanek
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Re: APOD: A Quadruple Lunar Halo Over Spain (2012 Dec 03)

Post by orin stepanek » Mon Dec 03, 2012 7:00 pm

Chris Peterson wrote:
orin stepanek wrote:Interesting photo; but was the fish-eye lens necessary to capture the view? I think it could be a beautiful photo if done with regular photography! Just MHO!
A 46° halo is specified by its radius. In other words, just capturing it completely (which this image does not) requires a vertical field of view of 92°, which (given typical image aspect ratios) means a horizontal FOV of 140°. That requires what is commonly called an ultra wide angle lens, which is probably what was used for this image (not a fisheye).
Thanks for the explanation Chris! 8-)
Orin

Smile today; tomorrow's another day!

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Re: APOD: A Quadruple Lunar Halo Over Spain (2012 Dec 03)

Post by Indigo_Sunrise » Mon Dec 03, 2012 7:27 pm

Chris Peterson wrote:
Indigo_Sunrise wrote:Can someone please explain the difference between the '46* halo' and the 'infralateral arc'?
In that image, they look like they are part of the same halo/arc.... :?
The two are formed by different mechanisms. By all accounts, they can be difficult to distinguish from each other, and are easily confused. There's some good information here.

From the link you provided:
The lower colourful halo some 46° below the sun is an infralateral or circumhorizon arc. Note the greens and blues which would not be present in a 46° halo.
But in the image it looks as though the 46* halo is merely a continuation of the infralateral arc, since they both look as though they have the green and blue colors. Wouldn't that mean there are only THREE lunar halos in the image for today......? Or where would the 'separation' between the two halos be?


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Re: APOD: A Quadruple Lunar Halo Over Spain (2012 Dec 03)

Post by Starlight Lover » Mon Dec 03, 2012 7:40 pm

:!: :?: :idea: :arrow: :| :mrgreen: :roll: :oops: :lol2: I Like to look at the sky and see the stars and Even the Bigg dipper!

Dark as night Lover

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Re: APOD: A Quadruple Lunar Halo Over Spain (2012 Dec 03)

Post by webolife » Mon Dec 03, 2012 7:56 pm

The CHA actually nearly parallels [ie. as an arc of a concentric circle with] the horizon, so does not correspond to an angle with respect to the central line of light/sight. In an unusual halo phenomenon in Seattle a couple years ago, there was a CHA projected nearly 30 degrees to both left and right of a pair of sundogs [22 deg halo].

We get quite a few irridescent clouds around Seattle, lots of sundogs, and the occasional pillar of fire. Usually just faint 22-deg moon halos, and occasionally a bright lunar coronal halo. The most surprising and amazing halos I've seen were a triple corona of the sun sharpened by its projection through a grove of leafless trees about five winters ago; and a fog bow on the shore of the Washington coast right at sunrise. I was out for a stroll on the beach, completely immersed in fog looking westward, with a nearly 360-deg fog bow surrounding my bright heiligenschein-ed shadow.

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Re: APOD: A Quadruple Lunar Halo Over Spain (2012 Dec 03)

Post by LocalColor » Mon Dec 03, 2012 8:03 pm

Very lovely photo today.

ronboy

Re: APOD: A Quadruple Lunar Halo Over Spain (2012 Dec 03)

Post by ronboy » Mon Dec 03, 2012 9:32 pm

A lunar Halo = What Neil Armstrong "really" said first. :lol2:

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Re: APOD: A Quadruple Lunar Halo Over Spain (2012 Dec 03)

Post by neufer » Mon Dec 03, 2012 9:46 pm

Chris Peterson wrote:
florid_snow wrote:
Getting corrected by Chris is like a dream come true, I always appreciate reading your clear comments on here.
Thanks... but you made me spit my coffee onto my keyboard when I saw that!
Glad I wasn't drinking coffee. :wink:
Art Neuendorffer

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Re: APOD: A Quadruple Lunar Halo Over Spain (2012 Dec 03)

Post by saturno2 » Mon Dec 03, 2012 11:56 pm

This picture is very beautiful
Moon Halo multifaceted.
Over Spain
This composition is great for a Christmas Card.
Truly

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Re: APOD: A Quadruple Lunar Halo Over Spain (2012 Dec 03)

Post by Wadsworth » Tue Dec 04, 2012 1:33 am

ronboy wrote:A lunar Halo = What Neil Armstrong "really" said first. :lol2:
:lol2:

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Re: APOD: A Quadruple Lunar Halo Over Spain (2012 Dec 03)

Post by neufer » Tue Dec 04, 2012 5:07 am

ronboy wrote:
A lunar Halo = What Neil Armstrong "really" said first. :lol2:
http://en.wikipedia.org/wiki/Hello wrote:
<<Hello, with that spelling, was used in publications as early as 1833.

According to the Oxford English Dictionary, hello is an alteration of hallo, hollo,
which came from Old High German "halâ, holâ, emphatic imperative of halôn,
holôn to fetch, used especially in hailing a ferryman
.">>
    • Twelfth Night Act 1, Scene 5

    VIOLA: Make me a willow cabin at your gate,
    • And call upon my soul within the house;
      Write loyal cantons of contemned love
      And sing them loud even in the dead of night;
      Halloo your name to the reverberate hills
      And make the babbling gossip of the air
      Cry out 'Olivia!' O, You should not rest
      Between the elements of air and earth,
      But you should pity me!
Art Neuendorffer

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Re: APOD: A Quadruple Lunar Halo Over Spain (2012 Dec 03)

Post by RedFishBlueFish » Tue Dec 04, 2012 1:51 pm

Chris Peterson wrote:
RedFishBlueFish wrote:What is the bright blue spot in Orion, just outside the inner halo at about 5 o'clock: UFO, Healing Brush gone wrong, or some sort of reflection within the lens?
It appears to be an internal reflection. I see a subtle hexagonal structure aligned with the lunar diffraction spikes, created by the 6-leaf iris in this lens.
Yes, I do believe that you are correct.

The moon is also the same shape.

I was hoping for UFO though :ssmile:

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Re: APOD: A Quadruple Lunar Halo Over Spain (2012 Dec 03)

Post by JohnD » Tue Dec 04, 2012 10:43 pm

Without showing disrespect, will anyone who wishes to post about how lovely this picture or any other will be on Christmas Card please do so in the Christmas card thread?
Astronomical pictures are undoubtedly beautiful, but an excess of oohing and ahhing is inappropriate.

Christmas?
Bah! Humbug!

Scrooge

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Re: APOD: A Quadruple Lunar Halo Over Spain (2012 Dec 03)

Post by owlice » Tue Dec 04, 2012 11:03 pm

Oohing and ahhing is completely appropriate, whether in excess or done sparingly.

Some publications are purchased for the pictures, even if the articles are excellent! :D
A closed mouth gathers no foot.

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Re: APOD: A Quadruple Lunar Halo Over Spain (2012 Dec 03)

Post by Beyond » Wed Dec 05, 2012 12:07 am

Well said, owlice, Guardian of the Codes, administrater, and Queen of the ooooooooooh-ers. :yes: :thumb_up: :mrgreen:
To find the Truth, you must go Beyond.

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Re: APOD: A Quadruple Lunar Halo Over Spain (2012 Dec 03)

Post by astrosirius » Thu Dec 06, 2012 3:12 am

Una preciosa imagen del Halo de la luna en pleno Invierno, felicidades!!
Google Translate wrote:A beautiful image of the Moon Halo in winter, congratulations!
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Last edited by bystander on Thu Dec 06, 2012 3:40 am, edited 1 time in total.
Reason: Added translation. This is an 'English only' board, please read the rules.