X-Galaxy is an 3D animated OS X-style nebula screensaver. It is based on the OS X-style nebula screensaver of the same concept.
X-Galaxy has well structured graphics that are truly mesmerising. The package actually comes with two animated screensavers X-Vortex and X-Galaxy. Although it is fairly basic with no configurable options, if you are a fan of Apple's space-themed wallpapers, then this will be right up your alley.
Both screensavers are lightweight and are not too taxing on your hardware, with no lag or visual distortions present when running.
The latest version is optimized for OS X 10.8.
Note: If you use two monitors make sure the "main screen only" is activated (see the README file included in the download).