Hot off the presses, here’s a stunning full-disc solar photo by the inimitable Alan Friedman, taken on November 6, 2011 from his location in Buffalo, NY. Absolutely gorgeous!
The enormous sunspot region AR 1339 can be seen just right of the center of the Sun. It’s nearly 17 times wider than Earth!
Hydrogen alpha (Ha) is a specific wavelength of light (656.28nm) emitted by hydrogen atoms. By filtering for just this wavelength of light, details of the Sun’s photosphere can be made out whereas otherwise they’d be lost in the glare of our home star.
Image © Alan Friedman. All rights reserved.