January 9, 2014 - NewsUseful background reading on aurora http://t.co/3J… Useful background reading on aurora swpc.noaa.gov/info/Aurora.pdf 4 page PDF – Old but well written.
RT @Nightskyonline: Useful background reading on aurora http://t.co/3JjWkQwJi5 4 page PDF – Old but well written.
RT @Nightskyonline: Useful background reading on aurora http://t.co/3JjWkQwJi5 4 page PDF – Old but well written.