Red Southern Lights

February 7, 2012 8:56 AM

A lovely time-lapse of the Aurora Australis - The striking red color is the result of charged particles from the sun exciting oxygen atoms high in the atmosphere.

More details, including some beautiful stills, can be found here.

posted by quin (15 comments total)

Wow. I just love these time-lapse videos. Thanks quin!

Can anyone in the southern hemisphere comment on the apparent brightness of the Milky Way down there? I know it's more visible than it is up here in the frigid north, but is it anywhere near as spectacular to the naked eye as it is in this video?
posted by hamandcheese at 9:06 AM on February 7

Thanks! This was a visual treat.
posted by Lynsey at 9:32 AM on February 7

Can anyone in the southern hemisphere comment on the apparent brightness of the Milky Way down there?

And the 2 big blobs next to it... those would be the Magellanic clouds, right?
posted by Hairy Lobster at 9:35 AM on February 7

Interesting. So the aurora is green/blue in the north and red/orange in the south? I did not know that.
posted by crunchland at 10:08 AM on February 7

"And the 2 big blobs next to it... those would be the Magellanic clouds, right?"

Yeah. I have no idea why this matters so much to me, but I think seeing them is about the only stargazing thing that I'd get really excited about.

I have a lifelong interest in astronomy, but not so much in actually looking at the stars. I was more interested in astrophysics, particularly cosmology, and that's the direction I was aiming for when I briefly majored in physics.

Years later, when I dated an astrophysicist, she did take me out stargazing one night and it was fun. Still, as beautiful as the night sky is—and scenes like these are incredibly beautiful—I guess I sort have always felt like, to me, looking at stars in the sky is to the beauty of astronomy as looking at shelves of books in a library is to the beauty of books.

...but the incredible sight of the Milky Way and the Magellanic Clouds in videos and photos like these does, nevertheless, make me catch my breath and be amazed.

I've never seen aurora. The red in this is exquisite—as it happens, red is my favorite color. Thanks for this post and these links!
posted by Ivan Fyodorovich at 10:09 AM on February 7

What I've never worked out is how people get these fantastic shots of the stars without any star trails. Even when I try really pretty short exposures (tens of seconds) I get these horrible blurs while those shots (which I'm assuming were in the minutes range from the trails left by ships) have nothing. What the hell gives?

Also - It never occurred to me before but are the southern lights always red and the northern ones green? The planet has port and starboard...?
posted by sodium lights the horizon at 2:09 PM on February 7

Shorter exposure times enabled by more sensitive film/sensors?
posted by Ivan Fyodorovich at 2:11 PM on February 7

Possibly - but if so, those ships are going at a hell of a speed...
posted by sodium lights the horizon at 2:15 PM on February 7

sodium lights the horizon: It never occurred to me before but are the southern lights always red and the northern ones green?

Nope. From Antarctic Connection's page on The Aurora Australis - Southern Lights:

What are the Colors of the Aurora?
Auroral displays appear in many colors with pale green and pink the most common. However, different shades of red, yellow, green, blue, and violet have all been observed. The brightest auroral color is generally a green light emitted by excited oxygen atoms. A red diffuse glow results from another oxygen atom transition. A purple color results from a transition in a Nitrogen molecular ion. The mixture of the major green, red and purple emissions may combine to give aurora a general 'whitish' appearance. The color variations are a product of the altitude of the storm, and the density and composition of the ions at that altitude. The folding effect results from the electric field induced on either side of the auroral curtain by the electrons.

The page also discusses the locations where you can see an aurora:

Where do Auroras Occur?
The global distribution of auroral activity is an oval around the magnetic poles in both hemispheres. As the level of magnetic disturbance of the Earth's magnetic field increases, the oval of auroral activity expands equatorward. Known as 'Aurora borealis' in the north, auroras occur in the upper atmosphere of both poles and are occasionally visible from middle latitudes as a dark red glow near the poleward horizon.

With that, it sounds like red might be more common farther from the poles, but I could be wrong.
posted by filthy light thief at 2:38 PM on February 7

How come the Milky Way is still very visible when the sun has risen?
posted by dov3 at 3:14 PM on February 7

The apparent brightness of the Milky Way in Australia is nothing like as bright as it appears in these shots. It's the same Milky Way, even though we're looking at a different piece of it. To put things in perspective, I can't see the Magellanic Clouds from the suburbs; I can just make them out from the suburban fringe; and I can see them reasonably easily from the countryside if it's dark. The photographer has positioned himself in a very dark area, looking out over a dark sea, and he's taken long exposures to make the stars seem brighter. Also, he's probably using a very good lens that admits a lot of light.

The film is made up of made of long exposures joined together. They're not very long exposures, though, because the star trails are hardly visible and the trails of the swiftly-moving meteorites take more than a single frame. Another reason the star trails aren't very long is that the camera is pointed towards the south pole, so the stars in the camera's field don't appear to be moving rapidly. The stars at the edge of the frame do look distinctly elliptical, and if I were feeling clever I could probably work out the length of the exposure from the shape.
posted by Joe in Australia at 4:19 PM on February 7

"What I've never worked out is how people get these fantastic shots of the stars without any star trails. Even when I try really pretty short exposures (tens of seconds) I get these horrible blurs while those shots (which I'm assuming were in the minutes range from the trails left by ships) have nothing. What the hell gives?"

from the blog:
30 seconds, f/2.8, ISO 3200
at 14-20 mm on FF sensor you can go up to 30 seconds without noticeable star trails.

"How come the Milky Way is still very visible when the sun has risen?"

I think that's the moon rising. See this timelapse from the Chile VLT array: the first clip starts with sunset (with the mountains still brightly lit by moonlight), then a later moonset, followed by the Milky Way rise and finally sunrise.
posted by jjj606 at 6:04 PM on February 7

Here's some northern lights.
posted by crunchland at 6:58 PM on February 7

Hobart, 1991. The fuckers rushed back in excited and stood in my doorway with grins on their faces.
"Did you see it? Wasn't it fantastic! Oh man, I am soo stoked, that was the best thing ever!"
"What are you talking about?" I asked
"The aurora, aurora aurora yeah yeah, aurora, the aurora."
"Wha? Why?"
"Oh. We've been watching it from the front deck. And, ah, thought you must be seeing it from somewhere else... ah, um.."
"I've been in here working." Fuckers.
"Sorry, yeah sorry, it was awesome, sorry, wow that was great, sorry, fantastic."

***

Fairbanks, Alaska, 2000. We woke and crawled out of our tent.
"Fantastic, awesome, incredible, I hope my photos worked."
"What are you talking about?" he said.
"The aurora!"
"Wha? Why?"
"Well, I thought about waking you but you'd been such a jerk to me last night I realised I'd enjoy it more alone.

***

Can anyone in the southern hemisphere comment on the apparent brightness of the Milky Way down there?

I live in rural Australia at an altitude of 1000m or 3330ft with absolutely no light pollution. Not every clear moonless night is this bright but many are. Sometimes the night sky here is the biggest consolation for living so far from a freakin' shop.
posted by Kerasia at 7:16 PM on February 7

There's not nearly as much light pollution in the cities in Australia where I've lived as there is in the cities in the US where I've lived. I've only seen the Milky Way that brightly when I've been out in the country but I could, for example, count more of the Pleiades by naked eye from my backyard in central Adelaide than I could from anywhere I'd lived in the US.
posted by gingerest at 7:17 PM on February 7