When Wisconsin sky-watcher Brian Larmay was out for a stroll on the night of April 2, he noticed a faint glow near the North Star. Racing for his camera, Larmay captured the ethereal colors of auroras over Pembine (map)—farther south than the northern lights usually appear.
"My adrenaline was in overdrive as I watched the pillars of light pulsate brighter and brighter and then fading as subtly as they arrived," Larmay said in an email to National Geographic News. (Related pictures: "Huge Solar Storm Triggers Unusual Auroras.")
Aside from dipping into northern U.S. states such as Wisconsin and Minnesota, this early April sky show was unusual because it featured several so-called deep-sky auroras. These light shows are often faint to invisible to the naked eye but come alive in long-exposure pictures, just as astrophotographers need long exposure times to capture details in very distant "deep sky" objects such as galaxies and nebulas. (Find out how to "see" beyond the Milky Way from your backyard this month.)
To create this auroral "sunset," Larmay used a digital camera set for a 30-second exposure time.
New Aurora Pictures: Deep-Sky Lights Revealed
Sometimes invisible to the naked eye, faint auroras as far south as Wisconsin sprang to life in long-exposure pictures taken last week.