Nov. 14, 2011 — Our sun is seen in all its magnificence in this panorama created by photographer Alan Friedman from his home in Buffalo, NY. The photos comprising this image were taken in Hα (hydrogen alpha) light on Nov. 6, 2011.
The enormous sunspot region AR 1339 can be seen just right of the center of the sun. The largest active region seen since 2005, it's wider than Jupiter, and nearly 17 times wider than Earth!
Hydrogen alpha is a specific wavelength of light — 656.28nm to be exact — emitted by hydrogen atoms. By using a filter for just this wavelength of light details of the sun's photosphere can be seen, whereas otherwise they'd be lost in the glare of our home star.
Image © Alan Friedman. All rights reserved. Used with permission.