This image was taken at the Phoebe Waterman Haas Public Observatory on April 17, 2013 at 11:58 am EDT, with a hydrogen-alpha telescope.
Most of the action is on the bottom half of this image. Several prominences can be seen along the bottom edge of the Sun, including one that looks like a fountain or a whale tail. Prominences occur when a magnetic loop sticks out of the Sun. Plasma from the sun travels along the protruding loop, causing it to look bright against space. There are a few small sunspot groups (cooler areas on the Sun), each surrounded by brighter areas, called plages.
Telescope: Lunt 100 mm hydrogen-alpha
Camera: Lumenera SKYnyx 2-2M