Aurora Information

 

Aurora photographed by Jan Curtis

Photo by Jan Curtis.

 

 

Aurora Information

 

The Aurora Borealis can be seen from almost anywhere in the vicinity of Fairbanks and along this latitude throughout the polar regions. While the aurora is sometimes visible in Anchorage and the Mt. McKinley area, Fairbanks is known worldwide for its spectacular auroral displays. Robert Behren’s fabricated steel archway sculpture, called “Solar Borealis” greets visitors at the Fairbanks International Airport and honors the arctic Aurora Borealis.

 

Fairbanks sits under what is called the “auroral oval”, a ring-shaped region
around the North Pole where auroras occur. Statistically, Fairbanks averages 243 nights per year of auroral activity. However, some of these nights occur during the summer, when Fairbanks is enjoying nearly 24 hours of daylight, and the aurora, like the stars, is not usually visible.

 

Auroras are seen frequently on clear winter nights in Alaska from late evening through the early morning hours. Intense auroras can be seen in the continental U.S., particularly in the north, when solar activity is high.

 

According to Assistant Professor of Physics Neal Brown, the aurora is likely to be visible from September to March and especially around the time of the equinoxes (September 21 and March 21). The spring months of January through April are often the best time to view the aurora because of better weather, however fall can be just as cooperative weather-wise. Best viewing time is at 1:30 a.m. daylight saving time in Alaska’s time zone.

 

From mid-August through the beginning of May, weekly forecasts of auroral activity can be accessed through the GI’s Website at:

 

http://www.gi.alaska.edu or http://www.gi.alaska.edu/cgi-bin/predict.cgi

Auroral predictions are as good as can be expected. No prediction is 100% guaranteed! We wish you the best of luck in your aurora viewing endeavors.

 

 


 

Aurora Tidbits:

 

Auroras occur in ring-shaped regions around the North and South geomagnetic poles. The auroras in the North are called the Aurora Borealis; in the South, they are called the Aurora Australis. These auroras are mirror images of each other.

 

The lower edge of the auroral curtain is 60 to 70 miles above the Earth, which is about ten times higher than a jet aircraft flies, and extends about another 60 miles up into the ionosphere. Earth’s magnetosphere protects us from the direct effects of the solar wind, but currents created by changing magnetic fields accompanying the aurora can seriously disrupt radio communications, radio navigation, some defense-related radar systems, and power transmission lines. They also can cause corrosion in pipes, including the Trans-Alaska Pipeline.

 

 An aurora acts as a generator that produces up to 10 million megawatts of electrical power. Auroral intensity varies with levels of solar activity, which seem to follow an 11-year cycle. That cycle is characterized by erratic bursts of solar flares at the high end of the cycle and relatively stable solar activity at the low end. A few years after a maximum year of solar activity, auroras in high latitudes are brilliant. The last solar maximum was in 2000-2001.

 

 


 

 

What Causes the Aurora?


Scientists at the Geophysical Institute (G.I.) study the aurora using rockets launched from Poker Flat Research Range. Using information collected by these rockets, scientists have determined what causes the aurora. Scientists at the Geophysical Institute also have watched the aurora from space, having received a federal grant to design special cameras for the space shuttle to take pictures of the aurora.

 

 Like a neon sign, auroral light is produced by a high-vacuum electrical discharge. The combination of an electrical discharge and air molecules gives it color. Auroras are similar to color television images. In the picture tube, a beam of electrons controlled by electric and magnetic fields strikes the screen, making it glow in a variety of colors.

 

 The sun, a hot ball of gases, continuously blows electrically charged particles from its outermost edges, creating solar wind. The solar wind travels to Earth in about three days. Auroras occur when electrically charged wind that blows through the solar system is pulled close to Earth at the poles by its magnetic field.

 

 Because Earth’s magnetic field prevents the solar wind from penetrating our atmosphere, its solar particles stream around our planet, encasing Earth and its magnetic field within a cometshaped cavity called the magnetosphere.

 

Auroral color depends on the type of atoms and molecules struck by the energetic particles that rain down along Earth’s magnetic field lines in the discharge process. Each atmospheric gas glows with a specific color.

 

Green: The brightest and most common auroral color, a brilliant green-yellow, is produced by oxygen atoms at roughly 60 miles altitude.

Blue: Ionized nitrogen molecules produce blue light. Purple: Neutral nitrogen molecules create purplish-red lower borders and rippled edges.

Red: High-altitude oxygen atoms (about 300 miles above the Earth) produce rare, all- red auroras. Red auroras are characterized by a red glow. Because they occur high in the sky, you can see them from far away. For instance, people in Chicago can see a red aurora over southern Canada.

 

 

Aurora photographed by Jan Curtis

Photo by Jan Curtis.

 

Please feel free to contact the Geophysical Institute Information and Education Outreach Office for more information:
Phone: (907) 474-7558
Fax: (907) 474-7125
Email: info [at] gi [dot] alaska [dot] edu

 


Watching the Aurora

 

Aurora photographed by Jan Curtis

Jan Curtis photo

 

 

The Aurora Borealis can be seen from almost anywhere in the vicinity of Fairbanks and along this latitude throughout the Polar Regions. While the aurora is sometimes visible in Anchorage and the Mt. McKinley area, Fairbanks is known worldwide for its spectacular auroral displays. Fairbanks sits under what is called the Auroral Oval, a ring-shaped region around the North Pole where auroras occur. Statistically, Fairbanks averages 243 nights per year when it is possible to see the aurora while Anchorage experiences and average of 100 nights per year. In order to experience the greatest chance of success in searching for the aurora, we recommend leaving the lights of the city.

 

According to Professor Emeritus Neal Brown, the aurora is more likely to be seen around the time of the fall and spring equinoxes, September 21st and March 21st. Also, the months before and after the equinoxes are good
times to see the aurora; so, observations of the aurora are recommended between August 21st and October 21st, in the fall and between February 21st and April 21st, in the spring. Christmas time, being near the solstice, offers poor viewing possibilities. While spring is often the best time to view the aurora because of a better chance for clear and cold weather, fall can be just as cooperative weather-wise. Truly, the Northern Lights can occur almost anytime, chances of seeing them improve immensely with clear, dark skies. Although it is difficult to say with any certainty when you will be able to view the aurora, if you are patient and plan to spend at least a week watching the sky and waiting, you have a very good chance of being rewarded for your wait, with at least one night of the beautiful lights of the aurora visible.

 

Please feel free to contact the Fairbanks Convention & Visitors Bureau for more information on places and locations to view the aurora around Fairbanks. They will have a lot of information available to you for
planning your trip.

 

Fairbanks Convention & Visitors Bureau
550 First Avenue
Fairbanks, Alaska 99701- 4790
URL: http://www.explorefairbanks.com/fairbanks/html/nonfl ash.html
Phone: (907) 456-5774
Fax: (907) 452-4190

 

 


 

 

Photographing the Aurora

 

A 35 mm camera on a tripod equipped with a cable release is a must for any aurora photographer. Use a wide-angle 24 mm to 50 mm lens and set it to the largest or second largest aperture opening (numerically, this will be the smallest or second to smallest f-stop) to avoid distortion of bright star images (usually f/1.4 to f/2.8). Exposures of 5 to 15 seconds work well unless the aurora is faint or mostly stationary, in which case the exposure time should be doubled. If the aurora is bright, moonlight and city light should not interfere and can offer an interesting foreground. Never use filters because they could cause internal reflections. If it is very dark, a silhouette of a tree or lit cabin will certainly add to the scene. Video cameras are not sensitive enough to successfully record the aurora. Because aurora occurs under clear skies, photographers will often be shooting in temperatures well below zero. Since cold saps camera batteries, it is best to use an older camera with a mechanical shutter instead of one that is fully automatic. Cold also makes plastic cable releases brittle, so use a wire-mesh-covered or a cloth-covered cable release. At minus 40 Fahrenheit, all cameras will freeze in less than 10 minutes; before taking it inside to warm, place it in a zip-lock plastic bag to reduce condensation.

 

Tape the lens to infinity so that it doesn’t slip and cause your images to be out of focus. Don’t try for a 37th exposure; it might break the film, and it is best to overexpose your first frame on the roll so that the film processor knows where to start cutting your negatives. Wind your finished roll of film slowly so that it doesn’t shatter or cause static buildup (this will appear as scratches). While Kodak film processing mailers are generally reliable, it may be worth the extra cost to have the film processed through a custom photo lab. The custom lab route will save the film from being lost in the mail or scratched in an automated process.

 

While slower speed film (print or slide) has better grain resolution; making for a sharper image (especially when enlarged), it may be too slow to record the fine detail structure of the aurora. I recommend using 400 speed film, which is a good compromise between detail and quality of the image. Different films will emphasize different colors of the aurora, so experimentation is advisable. Bracketing your exposures (i.e. one 5 seconds, 10 seconds and 15 seconds) will give you the characteristics of the film. Even in a roll of 36 exposures, there are only a few shots that are acceptable to me. So the lesson is, since the
aurora displays are unpredictable, patience is the key to success.

 

Aurora photographed by Jan Curtis

Jan Curtis photo

 

 


 

 

Aurora Links

 

 Alaska Science Forum.

http://www2.gi.alaska.edu/ScienceForum/aurora.html

 

Asahi Aurora Classroom.

http://www2.gi.alaska.edu/asahi/

 

Aurora Alive.

http://www.auroraalive.com/

 

    Aurora Flip Book.

www.windows.ucar.edu/teacher_resources/flipbooks/aurora.pdf

 

 Aurora Forecast.

http://www.gedds.alaska.edu/AuroraForecast/

 

 Auroral Activity Extrapolated from NOAA.

http://www.swpc.noaa.gov/pmap/

 

 Auroral Colors and Spectra.

http://www.windows2universe.org/earth/Magnetosphere/aurora.html

 

Digital Library for Earth Science Education.

www.dlese.org/library/index.jsp

 

IPS Radio and Space Services.

http://www.ips.gov.au/Geophysical

 

IRF: Swedish Institute of Space Physics.

http://www.irf.se/Popular/?docid=1132

 

 Kjell Henriksen Observatory.

http://kho.unis.no/

 

Latitude 64 Photos by Jan Curtis.

http://latitude64photos.com/

 

Libguide: Auroras at Solar Minimum.

http://libguides.library.uaf.edu/aurora

 

NASA: Watch How Auroras Form.

http://www.nasa.gov/mpg/133551main_live_aurora.mpg

 

National Earth Science Teachers Association.

www.nestanet.org

 

Physics of the Aurora: Earth Systems.

www.meted.ucar.edu/hao/aurora/

 

Solar Cycle Prediction.

http://solarscience.msfc.nasa.gov/predict.shtml    

 

Solar Terrestrial Dispatch.

http://www.spacew.com/

 

Space Weather Center.

www.spaceweathercenter.org

 

The Aurora: Information and Images.

http://www.pfrr.alaska.edu/aurora/index.html

 

The Aurora Page from Michigan Technological University.

http://www.geo.mtu.edu/weather/aurora/

 

The Aurora Today.

http://www.windows2universe.org/spaceweather/quicklook4d.html

 

Today’s Space Weather: From the Space Environment Center in Boulder, Colorado.

http://www.sec.noaa.gov/today.html

 

What is the Aurora?

www.scostep.ucar.edu/comics/books/ste_aurora_e.pdf

 

What is the Color of Space?

http://www.ucar.edu/communications/staffnotes/0705/space.shtml

 

 

In addition to great information on the web, don’t forget your local library! Ask your librarian about books listed in our aurora bibliography if you are working on a report or research paper.

UAF is an AA/EO employer and educational institution. Last update Winter 2010 by Webmaster.
Copyright © 2010 Geophysical Institute, University of Alaska Fairbanks.