APOD: In Green Company: Aurora over Norway (2020 Nov 09)

[APOD Robot]

In Green Company: Aurora over Norway

Explanation: Raise your arms if you see an aurora. With those instructions, two nights went by with, well, clouds -- mostly. On the third night of returning to same peaks, though, the sky not only cleared up but lit up with a spectacular auroral display. Arms went high in the air, patience and experience paid off, and the creative featured image was captured as a composite from three separate exposures. The setting is a summit of the Austnesfjorden fjord close to the town of Svolvear on the Lofoten islands in northern Norway. The time was early 2014. Although our Sun has just passed the solar minimum of its 11-year cycle, surface activity should pick up over the next few years with the promise of triggering more spectacular auroras on Earth.

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[WWW]

Are they sure that isn't Mount Crumpit?

[Ann]

Are they sure that isn't Mount Crumpit?

In Green Company: Aurora over Norway. Image Credit & Copyright: Max Rive.

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Mount Crumpit. Illustrator: I don't know.

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Well, they are similar... but on Mount Crumpit it is usually only the Grinch that is green.

Ann

[orin stepanek]

Nice Aurora! I would never stand on that peak!

[Tszabeau]

That does not help my vertigo but... WOW!

[Guest]

I’ve been using this photo as my cell phone wallpaper for about a year. I altered it slightly though by blotting out the guy at the mountain top.

[neufer]

Are they sure that isn't Mount Crumpit?

Well, they are similar...but on Mount Crumpit it is usually only the Grinch that is green.

Mount Crumpit.

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Click to play embedded YouTube video.

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Austnesfjorden fjord arm

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<<Austnesfjorden is a fjord arm of the Vestfjord on the southeast side of Austvågøya in Vågan municipality in Lofoten . On the west side, from the north, Vestpollen , Sildpollen , Vatterfjorden and the bay Husvågen go off, while Austpollen goes off Austnesfjorden in the northeast. Local road on the east side to the somewhat smaller village Liland.>>

[dx_ray]

This is NOT an honest astrophotography. If you zoom in the image, you can see many manipulations, like patches with different size of noise, or star dots in different sizes. This means that, those patches come from different images. I guess such manipulation is to make the circular shape of the aurora.

Ethics statement: APOD accepts composited or digitally manipulated images, but requires them to be identified as such and to have the techniques used described in a straightforward, honest and complete way.

https://apod.nasa.gov/apod/lib/apsubmit2015.html

APOD has post this image several times, I think such manipulation should not be shown on APOD.

[Chris Peterson]

This is NOT an honest astrophotography. If you zoom in the image, you can see many manipulations, like patches with different size of noise, or star dots in different sizes. This means that, those patches come from different images. I guess such manipulation is to make the circular shape of the aurora.

Ethics statement: APOD accepts composited or digitally manipulated images, but requires them to be identified as such and to have the techniques used described in a straightforward, honest and complete way.

https://apod.nasa.gov/apod/lib/apsubmit2015.html

APOD has post this image several times, I think such manipulation should not be shown on APOD.

The caption is very clear that the image is a composite of three exposures. That is normal photographic technique for any high dynamic range subject.

[BillBixby]

Nice Aurora! I would never stand on that peak!

Human lightning rod. Add a kite and a key for a simple experiment...

[orin stepanek]

Nice Aurora! I would never stand on that peak!

Human lightning rod. Add a kite and a key for a simple experiment...

[johnnydeep]

"I'm king of the World!". I suppose the other side of that mountain is a lot less steep than the side we see, or else how the heck did he manage to get up there?

Click to play embedded YouTube video.

[MarkBour]

I remember playing around with this image when it was posted 3 years ago. I thought I'd take another shot at investigating the locale (from my safe, warm, and comfortable chair).

Capture from Google Earth, click to expand

The best I can match this location and overall image is with:

https://earth.google.com/web/search/Aus ... iUR5a3JErA


If this view is correct, the nearest lighted roadway in the APOD is a road next to the village of Laupstad and the farther branch of the roadway goes out to the village Liland.

The water next to this roadway is therefore the inland end of the Austnesfjorden. The massif on the far side of the fjord would be the Langstrandtindan and Rulten.

So where would this place the photographer and his daring subject?
Somewhere near Pilan peak.

Pilan Peak photo on AllTrails.com

Google Earth around Pilan peak makes it appear more accessible than the APOD would suggest, but actually, I have no idea how difficult it is. I wouldn't trust Google Earth over a reliable topo map.

AllTrails rates the trek to Pilan as difficult.

One other thing. The overall shot would be facing pretty much south. If the time of year of the photo was around this time of year, then the sun would set pretty far to the south from that latitude in Norway, so in the APOD, having the sunset to the South-Southwest seems right.

[neufer]

non-distorted Pilan peak

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So where would this place the photographer and his daring subject?

Somewhere near Pilan peak.

Google Earth around Pilan peak makes it appear more accessible than the APOD would suggest, but actually, I have no idea how difficult it is. I wouldn't trust Google Earth over a reliable topo map.

AllTrails rates the trek to Pilan as difficult.

I wouldn't trust APOD's distorted image of Pilan peak with its non-distorted summit man.

[dx_ray]

This is NOT an honest astrophotography. If you zoom in the image, you can see many manipulations, like patches with different size of noise, or star dots in different sizes. This means that, those patches come from different images. I guess such manipulation is to make the circular shape of the aurora.

Ethics statement: APOD accepts composited or digitally manipulated images, but requires them to be identified as such and to have the techniques used described in a straightforward, honest and complete way.

https://apod.nasa.gov/apod/lib/apsubmit2015.html

APOD has post this image several times, I think such manipulation should not be shown on APOD.

The caption is very clear that the image is a composite of three exposures. That is normal photographic technique for any high dynamic range subject.

HDR should not affect stars. Please zoom in to 100% and take a closer look. Stars are messed up due to the manipulation. Can you recognize any constellations from this image?

[NCTom]

Chris, this has nothing to do with today's APOD, but I never followed up my question several days ago about the origin of gravity with the existence of mass. Thanks for the brief explanation which was probably the most I could come close to understanding. I had completely forgotten the Higgs boson and its relationship to mass and the nature of space/time. My physics classes were long before its discovery. Thanks again.

[gcvisel@gmail.com]

Why do (vivid) aurora look like curtains? Is that a map of the magnetic field there? Is there a flow of electricity happening with all those ions passing through?

Gerry

[neufer]

Why do (vivid) aurora look like curtains? Is that a map of the magnetic field there?

https://en.wikipedia.org/wiki/Aurora#Forms_of_auroras

Different Aurora forms

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Click to play embedded YouTube video.

<<According to Clark (2007), there are four main Aurora forms that can be seen from the ground, from least to most visible:

• A mild glow, near the horizon. These can be close to the limit of visibility, but can be distinguished from moonlit clouds because stars can be seen undiminished through the glow.
  
  Patches or surfaces that look like clouds.
  
  Arcs curve across the sky.
  
  Rays are light and dark stripes across arcs, reaching upwards by various amounts.
  
  Coronas cover much of the sky and diverge from one point on it.

Brekke (1994) also described some auroras as curtains. The similarity to curtains is often enhanced by folds within the arcs. Arcs can fragment or break up into separate, at times rapidly changing, often rayed features that may fill the whole sky. These are also known as discrete auroras, which are at times bright enough to read a newspaper by at night.

These forms are consistent with auroras' being shaped by Earth's magnetic field. The appearances of arcs, rays, curtains, and coronas are determined by the shapes of the luminous parts of the atmosphere and a viewer's position.>>

[neufer]

Is there a flow of electricity happening with all those ions passing through?

Schematic of the Birkeland or Field-Aligned Currents and the ionospheric current systems they connect to, Pedersen and Hall currents.

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<<A Birkeland current is a set of currents that flow along geomagnetic field lines connecting the Earth's magnetosphere to the Earth's high latitude ionosphere. In the Earth's magnetosphere, the currents are driven by the solar wind and interplanetary magnetic field and by bulk motions of plasma through the magnetosphere (convection indirectly driven by the interplanetary environment). The strength of the Birkeland currents changes with activity in the magnetosphere (e.g. during substorms). Small scale variations in the upward current sheets (downward flowing electrons) accelerate magnetospheric electrons which, when they reach the upper atmosphere, create the Auroras Borealis and Australis. In the high latitude ionosphere (or auroral zones), the Birkeland currents close through the region of the auroral electrojet, which flows perpendicular to the local magnetic field in the ionosphere. The Birkeland currents occur in two pairs of field-aligned current sheets. One pair extends from noon through the dusk sector to the midnight sector. The other pair extends from noon through the dawn sector to the midnight sector. The sheet on the high latitude side of the auroral zone is referred to as the Region 1 current sheet and the sheet on the low latitude side is referred to as the Region 2 current sheet.

The currents were predicted in 1908 by Norwegian explorer and physicist Kristian Birkeland, who undertook expeditions north of the Arctic Circle to study the aurora. He rediscovered, using simple magnetic field measurement instruments, that when the aurora appeared the needles of magnetometers changed direction, confirming the findings of Anders Celsius and assistant Olof Hjorter more than a century before. This could only imply that currents were flowing in the atmosphere above. He theorized that somehow the Sun emitted a cathode ray, and corpuscles from what is now known as a solar wind entered the Earth's magnetic field and created currents, thereby creating the aurora. This view was scorned by other researchers, but in 1967 a satellite, launched into the auroral region, showed that the currents posited by Birkeland existed. In honour of him and his theory these currents are named Birkeland currents.

Auroral Birkeland currents carry about 100,000 amperes during quiet times and more than 1 million amperes during geomagnetically disturbed times. Birkeland had estimated currents "at heights of several hundred kilometres, and strengths of up to a million amperes" in 1908. The ionospheric currents that connect the field-aligned currents give rise to Joule heating in the upper atmosphere. The heat is transferred from the ionospheric plasma to the gas of the upper atmosphere, which consequently rises and increases drag on low-altitude satellites.

Birkeland currents are also one of a class of plasma phenomena called a z-pinch, so named because the azimuthal magnetic fields produced by the current pinches the current into a filamentary cable. This can also twist, producing a helical pinch that spirals like a twisted or braided rope, and this most closely corresponds to a Birkeland current. Pairs of parallel Birkeland currents will also interact due to Ampère's force law: parallel Birkeland currents moving in the same direction will attract each other with an electromagnetic force inversely proportional to their distance apart whilst parallel Birkeland currents moving in opposite directions will repel each other. There is also a short-range circular component to the force between two Birkeland currents that is opposite to the longer-range parallel forces.>>

[Chris Peterson]

This is NOT an honest astrophotography. If you zoom in the image, you can see many manipulations, like patches with different size of noise, or star dots in different sizes. This means that, those patches come from different images. I guess such manipulation is to make the circular shape of the aurora.


https://apod.nasa.gov/apod/lib/apsubmit2015.html

APOD has post this image several times, I think such manipulation should not be shown on APOD.

The caption is very clear that the image is a composite of three exposures. That is normal photographic technique for any high dynamic range subject.

HDR should not affect stars. Please zoom in to 100% and take a closer look. Stars are messed up due to the manipulation. Can you recognize any constellations from this image?

There are many ways to capture wide dynamic range other than conventional HDR. I've seen a great many nighttime images that make it very difficult to detect constellations.

[dx_ray]

The caption is very clear that the image is a composite of three exposures. That is normal photographic technique for any high dynamic range subject.

HDR should not affect stars. Please zoom in to 100% and take a closer look. Stars are messed up due to the manipulation. Can you recognize any constellations from this image?

There are many ways to capture wide dynamic range other than conventional HDR. I've seen a great many nighttime images that make it very difficult to detect constellations.

Above posts had suggested the view is to south, and it should be wide angle photo, also you can see many bright stars in it. Together with location information, it is not hard to find constellations if stars are not manipulated.