A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Sean C
Date: 2014 Oct 18, 01:16 -0700
Although not directly related to navigation, I thought some here might find this website interesting:
It's basically an online orrery. It does have a feature which superimposes a "horizon line" through a given location on Earth, making it convenient for predicting planet visibility. I found it helped me better understand the apparent motions of the Moon, Sun and planets.
As a bonus, you can visualize the orbits of comets and the paths of the Voyager spacecrafts.