These images of the Sun were taken on the same day, on July 29, 2013. The images were taken at 11:53 am, 9:40 am, and 9:44 am, respectively.
This was a quiet day on the Sun, though there were a number of sunspot groups visible.
The purple image was taken with a calcium-K telescope, which lets through only one shade of deep violet light that reveals magnetic activity around sunspots. Look for large, dark magnetic disturbances, and bright splotches which are clouds of gas called plages.
The eggshell-colored image is the overall color of the Sun as seen by our eyes. The surface of the Sun produces yellowish-white light which is a combination of all of the colors of the rainbow. This is a good way to see sunspots in detail. The sunspots on this day were relatively small, though the one near the center is as large as the Earth.
The last image was taken with a hydrogen-alpha telescope, which lets through just one shade of red light. This reveals the atmosphere of the Sun. Look for arches of gas called prominences around the Sun, as well as sunspots, bright plages, and dark lines called filaments. Even on a quiet day, dramatic prominences like these are sometimes visible.
Telescopes: Lunt 60mm calcium-K and Lunt 100mm hydrogen-alpha. Note: The hydrogen-alpha telescope was also used to take the middle image. The filter was tuned away from the hydrogen-alpha wavelength, letting through another shade of red light which shows essentially the same features as a white-light filter. The images were all taken with a black-and-white camera, and color was added back in later.
Camera: Lumenera SKYnyx 2-2M