APOD: A Symphony in Northern Winter Skies (2019 Mar 22)

Comments and questions about the APOD on the main view screen.
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APOD: A Symphony in Northern Winter Skies (2019 Mar 22)

Post by APOD Robot » Fri Mar 22, 2019 4:11 am

Image A Symphony in Northern Winter Skies

Explanation: Despite the cold, a chance to view the shimmering northern lights coaxed this skygazer onto the frozen surface of Lake Superior on the west coast of the Keweenaw Peninusla and offered this nocturnal crescendo as a reward. A northern late winter night sky also plays across the panoramic composition of images made between 10pm and 1am on the night of February 28/March 1. At left, a faint band of Zodiacal light rises sharply from the horizon crossing Mars and the Pleides star cluster. Both the distant galaxy M31 and our own Milky Way shine above the greenish auroral arc. Navigational north pole star Polaris is centered above and accompanied on the right by the northern night's most recognizable asterism, the Big Dipper. Terrestrial lights include markers for two breakwaters on the the horizon near the center of the scene.

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Re: APOD: A Symphony in Northern Winter Skies (2019 Mar 22)

Post by Boomer12k » Fri Mar 22, 2019 4:48 am

An amazing image with so much going on...

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David_from_Slough_UK

Re: APOD: A Symphony in Northern Winter Skies (2019 Mar 22)

Post by David_from_Slough_UK » Fri Mar 22, 2019 12:57 pm

Great photo, but I'm puzzled. Why do the 'pointers' in the Big Dipper' not point towards the Pole star? Is it some kind of strange distortion with the wide-angle lens?

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Re: APOD: A Symphony in Northern Winter Skies (2019 Mar 22)

Post by orin stepanek » Fri Mar 22, 2019 1:08 pm

Great wallpaper shot! :D 8-)
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Re: APOD: A Symphony in Northern Winter Skies (2019 Mar 22)

Post by neufer » Fri Mar 22, 2019 2:00 pm

David_from_Slough_UK wrote:
Fri Mar 22, 2019 12:57 pm

Great photo, but I'm puzzled. Why do the 'pointers' in the Big Dipper' not point towards the Pole star? Is it some kind of strange distortion with the wide-angle lens?
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Re: APOD: A Symphony in Northern Winter Skies (2019 Mar 22)

Post by IIIIIKK » Fri Mar 22, 2019 4:28 pm

Hi,

I'm not sure that the bright centered star is Polaris because in relation to Big Dipper, it must be slightly above (except if it is caused by the distorsion of the lens or due to the projection).

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Re: APOD: A Symphony in Northern Winter Skies (2019 Mar 22)

Post by Ann » Fri Mar 22, 2019 7:09 pm

IIIIIKK wrote:
Fri Mar 22, 2019 4:28 pm
Hi,

I'm not sure that the bright centered star is Polaris because in relation to Big Dipper, it must be slightly above (except if it is caused by the distorsion of the lens or due to the projection).
Read the post above yours. :wink:

(But you're right - in reality, the pointers of the Big Dipper would point pretty much straight at Polaris, which they don't do in this picture.)

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Re: APOD: A Symphony in Northern Winter Skies (2019 Mar 22)

Post by alter-ego » Sat Mar 23, 2019 4:58 am

Ann wrote:
Fri Mar 22, 2019 7:09 pm
IIIIIKK wrote:
Fri Mar 22, 2019 4:28 pm
Hi,

I'm not sure that the bright centered star is Polaris because in relation to Big Dipper, it must be slightly above (except if it is caused by the distorsion of the lens or due to the projection).
Read the post above yours. :wink:

(But you're right - in reality, the pointers of the Big Dipper would point pretty much straight at Polaris, which they don't do in this picture.)

Ann
The image is most closely replicated by a form of cylindrical projection (sphere projected to a cylinder) which leads to distortions worsening toward the poles; not as severe as a Mercator projection but worse than more familiar images. From Stellarium, the images below show two projection algorithms, cylindrical and stereographic (sphere projected to plane) of identical fields of view. The latter (right image) is the same as or very close to typical camera images. The views are of the same APOD sky region, and from location close to the photographer. Also visible is the equatorial grid to show the continuity of distortions for both projections. The cylindrical projection (left) fits pretty well to the APOD. The stereographic projection looks more familiar. The pointer stars look more like pointer stars.
 
Cylindrical.JPG
Stereographic.JPG
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