Before we get into the weeds with aurora photography you should note that when you observe aurora with your eyes you do NOT see green flashing about. As I understand this, your eyes basically see almost pure black and white in a pitch black environment. It has to do with those rods and cones in your eye. They are not as sensitive to color when it is dark. So, what you see dancing across the sky is this gray curtain, with a tint of green . This photo was converted to black and white to demonstrate this fact. So where does the green come from? Well, it is actually there, but in a pure dark environment your eyes do not see the distinction between various colors in low light. Not to worry. Your camera sure does. My Nikon did a beautiful job, and so would another camera from another company. Why? The cameras digital chip is programed to process Red-Green-Blue, this gives you the multitude of colors that any digital camera can produce. The bigger and newer the chip the more colors you will see.
Ok. So it took me until page 3 to get to actual Aurora photos. Well here they are:
This was the night that the clouds moved in. The Aurora was pretty intense and we could not see it directly through the clouds. In a way it was like photographing automobile headlights through a thick fog. Very diffused light.
You can click on the photo to make it bigger, so you can see more detail.
There was NO Aurora!!!! So, what the heck. I sarted photographing the beautiful clear sky. You cannot believe how clear the night sky is in rural Alaska. Note. We were not standing outside in a Walmart parking lot. The Aurora Chasers would take us out to some remote location with-in about a 50 mile radius of Fairbanks. That way we had total dark skies. I would say a Bortal #1 (darkest rating you can get). See link to BORTAL SCALE:
BORTAL SKY DARKNESS SCALE
The night sky is so beautiful. Below you can clearly see Orion and Taurus the bull.
The below photo is rather unique because it appears that the bush is burning. I call it the Burning Bush photo, however, there is no fire. It just so happened that right on the horizon there was a red aurora at the same time I was photographing. How is that? Well actually it is not hard to understand. The density of the electrically charged particles generated by the sun determines how far down into our atmosphere it will penetrate. Side Bar: Our north pole is postively charged, and the plasma from the sun is negatively charged. As this solar energy enters our atmosphere it interacts with oxygen and nitrogen molecules. This produces a chemical reaction in-which various colors can be generated depending on the intensity of the oxygen/nitrogen content at the point of plasma interaction. The closer you get to the earths surface the denser the oxygen/nitrogen molecules. This variation in oxygen/nitrogen will determine which colors you see.
The green aurora which is most common, reacts with oxygen/nitrogen molecules at or about 60 to 100 miles up. If there is a heavy discharge of electromagnetic energy from the sun, the increased density of this emission will sink further down into our atmosphere, thus interacting with more nitrogen molecules. So, aurora color is contingent upon the interaction height above the surface of the earth. You can see, blue, purple, red etc. They say that yellow is very rare, but has been photographed. Actually, this principle is how neon signs generate different colors. However, they can use argon and other gasses to obtain various colors. COLORS OF AURORA FYI. I hope to go back to Fairbanks, with Aurora Chasers, around 2025 or 2026. That will be the time of the maximum intensity of the current solar sunspot cycle which the peak occurs every 11 years. At the peak of the solar cycle, there is a significant increase in electrical energy releases from the surface of the sun. At that point it may be quite common to see multiple colors when photographing (not viewing) the aurora. See what you missed by sleeping during 9th grade science class!. ha.