Saturday, November 7, 2009
The Astronomy Picture of the Day site has this cool image of the sun. The visible spectrum of hydrogen has 4 lines called the Balmer Series. I can see at least three of them myself, but the fourth is on the edge of my eyesight. To me the lines have the colors Red (656 nm), Blue (486 nm), Violet (434 nm) and Violet (410). This picture was take using a filter that only lets through the Hydrogen Alpha line, and then color inverted to appear blue. I'm not sure why they changed the color, but it looks cool. Take a look at the larger version of this picture at the link.
Image Credit & Copyright: Alan Friedman (Averted Imagination)
Link APOD: 2009 November 4 - Blue Sun Bristling