This is the default module, and is built into the After Dark control panel. If there is a problem running a module or your system is out of memory (the most common reason), After Dark runs Starry Night instead.
Blank Screen Only
Another screen saver option that is built into the After Dark control panel is "Blank Screen Only." This is useful for situations where you might not want distracting animations or sounds, and is as "simple" a module as FadeAway. Regardless of your selected module, you can temporarily invoke "Blank Screen Only" by holding down the Shift key as you move the mouse to the Sleep Now corner. (Sorry, this keyboard trick does not work with the sleep hot key.)