Friday, December 30, 2011

2011 in photos

By the month, choosing one photo for each month. This is quite hard for some months.

January: Cold and dark, as January tends to be in interior Alaska. The Sun is almost invariably pretty when it's up. A 3-in-the-afternoon visit to Chena Lakes yielded this shot.

Sunset at Chena flood control

February: Snowy! It snowed a lot in February. Compounded with the rest of the snow that had been piling up since October, my front porch was getting pretty deep.

Front Porch

March: The return of daylight! I drove down to Seward for the heck of it, saw this beached boat. The Sun reflecting off the snowy mountains was blindingly bright next to the shaded black paint, so I did this one as an HDR. I need to spend some more time in this area, it looks like a great place for sea kayaking.

Boat HDR

April: Denali in the springtime. For a few weeks before buses begin running, the park road is open to private vehicles as far as the Teklanika River (mile 30). Lee, Kate and I went on the first open weekend, drove as far as we could, then walked further. It's still the furthest I've been into the park. The cold days give clear views of the big mountain that are rarely seen in summer when all the people are here.

Denali in the distance

May: The weekend before I drove south to Arkansas I went for one last Alaska drive, down to the Denali Highway. It was not yet officially open for traffic, with lots of crazy warning signs suggesting instant death for anyone foolish enough to set foot tire on the road, but I found the road easily passable as far as Tangle Lakes. Saw lots of ptarmigan here, but my favorite shot had to be this one. Captures the feeling of the place perfectly.

Lost in Alaska

June: I spent around an hour chasing one particularly large dragonfly around a field to try and get a good in-flight shot. Dragonflies are fast, and getting it in focus was difficult. The effort paid off; the dragonfly is sharp, the light is good, the exposure is just right, and the out of focus background looks great. I didn't even have to crop it.

Dragonfly on the hunt

July: I stayed in Denver for two weeks where I spent the nights doing science in a private jet over thunderstorms. Look for me in NHK's 'Cosmic Shore' program, coming out on Discovery or National Geographic channel this spring :P I would post one of the sprite images I took with the high-speed camera, but they're all on my hard drive in Alaska, so how about a shot of the plane I flew in instead? Not the best picture I took this month, but probably has the best memories associated with it.

Storms in the distance

August: Driving along the south side of Denali I pull over to a decent view of the mountain, and a couple on vacation in Alaska pull in to see the view, then tell me 'the view was better a few miles back, we're going back.' So I follow them, and they were right, it's the best view of Denali I've ever seen. First you think 'oh, those are some big mountains'. Then you notice the shadow of the big mountain behind them. I ended up chatting with them for half an hour in the grass on the side of the Parks Highway, then we go our separate ways.

Denali Sunset from the south side

September: Aurora season is on! Having recently visited the Chatanika Dredge for the first time, I know I want it as a foreground for some aurora shots, so I head that way one night when the aurora forecast looks good. It ends up being the most memorable aurora I've yet seen, and I shoot for hours - two other guys with the same idea show up to shoot too, I wish I could see what they ended up getting. This picture doesn't even use the dredge, but looks up one of the tailing piles where the aurora appears to be streaming right out of the ground. The bright thing near the ground is the rising planet Jupiter.

Jupiter rising

October: Prime aurora season! Taken from my front porch during a brief break through an otherwise completely overcast sky, this shot currently has almost 20,000 views on Flickr, making it the most popular picture I've ever taken by a good margin.


November: This year I started experimenting with time lapse videos, and by the end of the year I was shooting quite a few of them. This one was taken from the roof of the Science Operations Center at Poker Flat, using an 8mm fisheye lens meant for all-sky cameras.

December: New Year's Eve Eve, driving through the bottoms in Paris, AR looking for something interesting, I spot a Great Horned Owl through the trees. I get a decent silhouette shot from a distance, then tramp off through the woods to try and get closer. The owl is too quick for me, but the sunset ends up being nice and colorful and interesting all on its own. Here, with some random agricultural equipment.

New Year's Eve Eve

Friday, December 23, 2011

Atmospheric Optics: The Glory

Airplane shadow in a glory

Spotted out the plane window over western Arkansas. Well, I said I was going to do more science posts, so why not start with this thing?

It's called a glory because it looks like the archetypal halo around the head of a saint. You see them directly opposite the Sun (so always below the horizon) in clouds of uniformly-sized drops of water. The exact formation mechanism is not known, but we have clues. The light in the center is polarized, so there must be at least one reflection inside the droplet, as well as two refractions (entering the drop and leaving the drop). And obviously, since we see them opposite the sun, the light must be bent around 180º (light going away from the Sun has to be turned completely around to come back to your eye). More sophisticated analysis shows most of the brightness is due to one reflection inside the water drop.

But it's not possible to turn the light 180º! At least, not with only one reflection and two refractions! So the explanation is that the light travels briefly along the surface of the drop as a surface wave. A diagram, and more explanation, can be found here.

A light ray enters one side of a drop and comes out the other side. A different ray enters where the first exits, and exits where the first enters. They interfere with each other, which causes the colored rings.

So the glory occurs directly opposite the Sun, which is the place where your shadow is. Therefore, your shadow will appear right in the center. In the top photo, you can tell I was sitting in the back of the plane. Like rainbows, glories aren't located at a physical place in space - every person sees a different glory. So if you and I were standing side by side looking at a glory, I would see the shadow of my head in the middle and yours off to the side, and you would see the shadow of your head in the middle and mine off to the side. Everyone sees their own glory, and no one else's.


That's the 'natural' picture of it - well, through a nasty, low-contrast aircraft window, anyways. I can make it easier to see by cranking the global contrast way up. The color has not been adjusted:

Stretched dynamic range Glory

Now you can clearly see the structure: Bright in the middle with colored rings outside.

Things which you'd never notice unless you knew to look.

Happy Winter Solstice

Solstice rock don't have a solstice rock?

Sunday, December 11, 2011

Visit to San Francisco

Golden Gate and Tree

I went to San Francisco this week for the American Geophysical Union fall meeting. I didn't present anything myself but was credited in a poster and a talk, both related to my sprites research from the summer. Oh, and a few of my photos made it into the talk as well, so that's scientific and photographic credit! Sooner or later I intend to do some science posts on sprites here on the blog. The NHK crew filmed myself and the rest of the sprites science team together as we watched new footage NHK got of sprites from the space station. Word is the TV special about our sprites exploits will air late this spring on either Discovery or National Geographic channel, I'll pass on the word when I hear more.The AGU meeting doesn't make for interesting blog material, but I did find a night to head out to one of the San Francisco beaches and do some nighttime ocean photography, which I really enjoy. First was the ruins of the Sutro Baths:

Sutro Baths and Seal Rocks

Pointy things Under the Sea

Then the rocky beach next door:

Land's End

Shore On the beach

Rocks, big and small

And of course I had to take a few shots of the Golden Gate bridge, though I tried to find a more interesting perspective than the 1000 tourist photos taken every day of this thing. Success or not? You be the judge:

Golden Gate and rocky cliff

I'm back in Fairbanks now. I hope to do a more substantive post soon, including more science, but probably not until this week (finals week!) is over. Enjoy the pictures for now.