March 30, 2015
Photographer: Greg Raniszewski;
Summary Authors: Greg Raniszewski; Jim Foster
Shown above are photos of the northern lights as observed looking out over Sleeping Bear Dunes National Lakeshore in Michigan. These lovely lights were produced by the huge solar storm on March 16, 2015 -- perhaps the most noteworthy in three years. The collision of solar wind particles with Earth's magnetosphere acts to accelerate the particles, forcing them down to altitudes of about 60 to 250 mi (100 to 400 km). It's here where they excite nitrogen and oxygen molecules, releasing photons that result in the breathtaking draperies, swirls and waves that on occasion liven the northern (aurora borealis) and southern (aurora australis) skies. A meteor adds a nice accent to the bottom image. Photos taken on March 17, between 9:00 and 11:00 p.m.
Photo details: Top - Camera Model: NIKON D600; Lens: 24.0-70.0 mm f/2.8; Focal Length: 24mm (35mm equivalent: 24mm); Aperture: ƒ/5.6; Exposure Time: 30.000 s; ISO equiv: 1600; Software: Adobe Photoshop Lightroom 5.7.1 (Windows). Bottom: Same except - Lens: 10.0-20.0 mm f/3.5; Focal Length: 10mm (35mm equivalent: 15mm); Aperture: ƒ/3.5; Exposure Time: 15.000 s; ISO equiv: 800.