APOD: Dueling Bands in the Night (2018 Feb 27)

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APOD: Dueling Bands in the Night (2018 Feb 27)

Post by APOD Robot » Tue Feb 27, 2018 5:08 am

Image Dueling Bands in the Night

Explanation: What are these two bands in the sky? The more commonly seen band is the one on the right and is the central band of our Milky Way galaxy. Our Sun orbits in the disk of this spiral galaxy, so that from inside, this disk appears as a band of comparable brightness all the way around the sky. The Milky Way band can also be seen all year -- if out away from city lights. The less commonly seen band, on the left, is zodiacal light -- sunlight reflected from dust orbiting the Sun in our Solar System. Zodiacal light is brightest near the Sun and so is best seen just before sunrise or just after sunset. On some evenings in the north, particularly during the months of March and April, this ribbon of zodiacal light can appear quite prominent after sunset. It has recently been determined that zodiacal dust was mostly expelled by comets that have passed near Jupiter. Only at certain times of the year will the two bands be seen side by side, in parts of the sky, like this. Here the two streaks of light appear like the continuation of the banks of the Liver River into the sky. The featured panorama of consecutive exposures was recorded about three weeks ago in North Jutland, Denmark.

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Re: APOD: Dueling Bands in the Night (2018 Feb 27)

Post by HellCat » Tue Feb 27, 2018 9:45 am

Two spelling errors:

The less commonly seem band... Should be SEEN
Only on certain times of the year... Only AT certain times...

heehaw

Re: APOD: Dueling Bands in the Night (2018 Feb 27)

Post by heehaw » Tue Feb 27, 2018 12:58 pm

HellCat wrote:Two spelling errors:

The less commonly seem band... Should be SEEN
Only on certain times of the year... Only AT certain times...
Hey that's NOTHING - look at these fools: they got their map upside down! http://odtmaps.com/detail.asp?product_id=McA-23x35

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Re: APOD: Dueling Bands in the Night (2018 Feb 27)

Post by De58te » Tue Feb 27, 2018 1:44 pm

heehaw wrote:
HellCat wrote:Two spelling errors:

The less commonly seem band... Should be SEEN
Only on certain times of the year... Only AT certain times...
Hey that's NOTHING - look at these fools: they got their map upside down! http://odtmaps.com/detail.asp?product_id=McA-23x35
Uh, what spelling errors? Every word technically is spelt correctly.

That is actually the correct view of the map. Even though there is no up or down in space, if you were looking down above the pole of that map, then you would see the Earth rotating correctly. Clockwise to match the hands on a clock.

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Re: APOD: Dueling Bands in the Night (2018 Feb 27)

Post by VPA » Tue Feb 27, 2018 2:23 pm

Why do they appear parallel ?

Usually the zodiacal light and the milky way appear perpendicular to each other because the ecliptic is tiltled compared to the milky way.

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Re: APOD: Dueling Bands in the Night (2018 Feb 27)

Post by Chris Peterson » Tue Feb 27, 2018 2:31 pm

VPA wrote:Why do they appear parallel ?

Usually the zodiacal light and the milky way appear perpendicular to each other because the ecliptic is tiltled compared to the milky way.
They are not parallel. They intersect somewhere between Taurus and Gemini, which is behind the camera in this view. We're just seeing a projection artifact such as is common in very wide angle images.
Chris

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Re: APOD: Dueling Bands in the Night (2018 Feb 27)

Post by VPA » Tue Feb 27, 2018 2:42 pm

I think I got tricked by the clouds, it must change the apparent direction of the zodiacal light in the picture (seems to go away from the milky way as you go up in the picture).
For exemple here is a similar image with clear sky, where the zodiacal light gets closer to the milky way as you go up in the picture.
https://amazingsky.files.wordpress.com/ ... y-way1.jpg

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Re: APOD: Dueling Bands in the Night (2018 Feb 27)

Post by Chris Peterson » Tue Feb 27, 2018 2:47 pm

VPA wrote:I think I got tricked by the clouds, it must change the apparent direction of the zodiacal light in the picture (seems to go away from the milky way as you go up in the picture).
For exemple here is a similar image with clear sky, where the zodiacal light gets closer to the milky way as you go up in the picture.
https://amazingsky.files.wordpress.com/ ... y-way1.jpg
They're still almost parallel in appearance in this projection.
Chris

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Are these Bands entiltled to be called parallel?

Post by neufer » Tue Feb 27, 2018 3:21 pm

Chris Peterson wrote:
VPA wrote:
Why do they appear parallel ?

Usually the zodiacal light and the milky way appear perpendicular to each other because the ecliptic is tiltled [sic] compared to the milky way.
They are not parallel. They intersect somewhere between Taurus and Gemini, which is behind the camera in this view.
We're just seeing a projection artifact such as is common in very wide angle images.
  • All meridians (longitude lines running from pole to pole) appear to be parallel at "the equator."
https://en.wikipedia.org/wiki/Parallel_(geometry) wrote:
<<In Euclidean geometry, parallel lines are lines in a plane which do not meet; that is, two lines in a plane that do not intersect or touch each other at any point are said to be parallel. In some other geometries, such as hyperbolic geometry, lines can have analogous properties that are referred to as parallelism. In spherical geometry, all geodesics are great circles. Great circles divide the sphere in two equal hemispheres and all great circles intersect each other. Thus, there are no parallel geodesics : all geodesics intersect.>>
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Re: APOD: Dueling Bands in the Night (2018 Feb 27)

Post by distefanom » Tue Feb 27, 2018 10:14 pm

Do someone noticed that the reflected lights, of the sky, which appear in the water (even thou a bit blurred), did not correspond to any part of the sky ?
Why?
Maybe photo-editing?

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Re: APOD: Dueling Bands in the Night (2018 Feb 27)

Post by geckzilla » Wed Feb 28, 2018 12:01 am

distefanom wrote:Do someone noticed that the reflected lights, of the sky, which appear in the water (even thou a bit blurred), did not correspond to any part of the sky ?
Why?
Maybe photo-editing?
The stars get smeared by movement in the water, so the brighter stars are especially noticeable. It's just something that happens with longer nighttime exposures featuring gently moving water. It does appear unusual, but it's not because of any editing. You can find other images similar to this with the same effect. What's neat is that the water reflection represents the relative brightnesses of the stars a little better than how they appear in the sky part of the image.
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Re: APOD: Dueling Bands in the Night (2018 Feb 27)

Post by neufer » Wed Feb 28, 2018 12:37 am

geckzilla wrote:
distefanom wrote:
Do someone noticed that the reflected lights, of the sky, which appear in the water (even thou a bit blurred), did not correspond to any part of the sky ?

Why? Maybe photo-editing?
The stars get smeared by movement in the water, so the brighter stars are especially noticeable. It's just something that happens with longer nighttime exposures featuring gently moving water. It does appear unusual, but it's not because of any editing. You can find other images similar to this with the same effect. What's neat is that the water reflection represents the relative brightnesses of the stars a little better than how they appear in the sky part of the image.
All that is true...but I also think this is a composite of at least 3 photos taken on the same night.
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Re: APOD: Dueling Bands in the Night (2018 Feb 27)

Post by astrokareny » Wed Feb 28, 2018 12:52 am

The sky portion of the image is beautiful, but I had the same issue with the star reflections in the water. There is nothing in the water that appears to correspond to the star patterns in the sky, star brightness notwithstanding. What am I missing about the principle of reflection? Maybe the "composite of at least 3 photos" is the explanation?

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Re: APOD: Dueling Bands in the Night (2018 Feb 27)

Post by Boomer12k » Wed Feb 28, 2018 1:56 am

It amazes me that you can see, I guess it is the Andromeda Galaxy, in these types of pictures.

WHY do they have to be "DUELING"... they look pretty harmonious to me... Why not "Harmonious Bands in the Night"?

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Re: APOD: Dueling Bands in the Night (2018 Feb 27)

Post by neufer » Wed Feb 28, 2018 3:22 am

Click to play embedded YouTube video.
Boomer12k wrote:
It amazes me that you can see, I guess it is the Andromeda Galaxy, in these types of pictures.

WHY do they have to be "DUELING"... they look pretty harmonious to me...
Why not "Harmonious Bands in the Night"?
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Re: APOD: Dueling Bands in the Night (2018 Feb 27)

Post by distefanom » Wed Feb 28, 2018 10:42 am

astrokareny wrote:The sky portion of the image is beautiful, but I had the same issue with the star reflections in the water. There is nothing in the water that appears to correspond to the star patterns in the sky, star brightness notwithstanding. What am I missing about the principle of reflection? Maybe the "composite of at least 3 photos" is the explanation?
Oh well, I'm in the same mind.... I think that the reflections in the water shows DIFFERENT IMAGE FEATURES than what can be seen directly using ordinary optical telescopes....
Maybe those "sploshes" thanks to water sloshing, shows something different image properties than the original image...
I.e. the AFOCAL method photography method, used sometimes in astronomy...
This method gives way more "optical power" to otherwise cheap machines...
here:
http://www.astronomyforbeginners.com/as ... afocal.php
or here:
http://darkerview.com/wordpress/?tag=afocal