This image of the Sun was taken on April 20, 2013 at 11:56 am EDT at the Phoebe Waterman Haas Public Observatory, with a hydrogen-alpha telescope.
A large sunspot group can be seen near the center of the image. There is also a smaller sunspot group near the bottom right side of the Sun’s disk. Both are surrounded by bright clouds called plages. A few prominences (magnetic loops with plasma traveling along them) can be seen around the edge. The dark lines that you see on the disk of the Sun are called filaments. Filaments and prominences are actually the same thing. The difference in their appearance is due to their position on the Sun. When a loop is on the disk of the Sun it appears dark in contrast to the rest of the Sun, but on the edge, it will appear bright against the darkness of space.
Telescope: Lunt 100 mm hydrogen-alpha
Camera: Lumenera SKYnyx 2-2M