Photos from our adventure to north of Fairbanks, Alaska; and beyond the Arctic Circle
March 9-13, 2014
March 9-10, 2014
In the sun's northern hemisphere, magnetic fields have opened up, allowing a stream of solar wind to escape into space. Such openings are called "coronal holes". A stream of solar wind flowing from this coronal hole should reach Earth on or about March 9th. Because the "spigot" is located in the sun's northern hemisphere, the stream will sail mostly north of our planet, delivering only a glancing blow to Earth's magnetic field. A glancing blow, however, might be enough to spark polar auroras. For reasons that researchers don't fully understand, spring is aurora season. With the northern vernal equinox just around the corner, even small gusts of solar wind can stir up geomagnetic activity.
It was a clear night, somewhere around -25°C. The wind was calm, thankfully. The moon was about 75% visible.
There are 33 pictures in this set from our position near Wiseman, Alaska which we reached after a short drive from Coldfoot, Alaska.
March 11-12, 2014
Nothing noted. A quiet night was expected
It was mostly overcast, somewhere around -10°C. The wind was light, around 5kts, The moon, when not behind clouds, was about 85% visible.
There are 8 pictures in this set from our position at Chena Hot Springs outside of Fairbanks, Alaska.
March 12-13, 2014
Although there was no forecast of strong activity, auroras were dancing high in the sky--very bright and very fast. The unexpected storm, a relatively minor G1-class event, was caused by a fluctuation in the interplanetary magnetic field (IMF). As March 12th turned to 13th, the IMF tilted south, opening a crack in Earth's magnetosphere. Solar wind poured in and fueled the display.
It was a mostly clear night, somewhere around -15°C. The wind was light, around 5kts with gusts to 15kts. The moon was about 90% visible.
I put together a series of pictures into the following GIF animations to show the movement of the Aurora. Click on each to see the sequence:
There are 25 pictures in this set from our position at Chena Hot Springs outside of Fairbanks, Alaska.
A little about the camera
- I used a Nikon D800 with a 16-35mm lens. The lens allows for an image to capture 107 degrees of the view
- The camera operating environment temperature is rated at 0 to 40°C, however I used it somewhere around -25°C. I suspect that while in use the circuitry produces enough radiant heat to keep the components at or above the 0°C threshold. The LCD was problematic at cold temperature and didn't always show an image (making it impossible to check the manual focus).
- To avoid condensation forming on, or in, the camera when moving from outside (cold, dry air) to the inside of a warm cabin (warm, humid air) I would cover the camera in a plastic bag. This also helped reduced frost forming on the lens.
- I used a tripod and remote cable. The remote cable connects through a GPS receiver that fits in the camera shoe so each picture is also geotagged.
- The ideal camera setting was with aperture priority mode using with the lowest possible f-stop (f4), ISO set to 1250, EV +2.7, and then manual focus. The typical exposure time was 4 to 6 seconds.
- The only casualty to the extreme weather was the tripod. The cold caused some of the plastic in the tripod head to become brittle and snap. Fortunately it was still usable in its degraded state, although far from ideal as it couldn't maintain a horizontal position. Time for a new lightweight travel tripod.
Questions or comments welcome. I reduced the size of the images shown on these link to conserve bandwidth and storage, if you would like full size copies please let me know.
Tony Di Bona