Xephem overview

This is a very quick discussion of a really cool Unix/Linux astronomical program called Xephem.  It's basically an ephemeris program but it does much more such as creates multiple types of astronomical charts and animated movies.  It's modular as well, allowing data from external sources to be imported.  Xephem differs from programs such as Kstars or Stellarium in that it is a professional application while others are geared towards hobbiest/amateur usage.

You can make animated GIFs which is really cool.  You can also add professional catalogs of data and ephemeris elements.  The "trail" feature is cool, it lets you trace out the path of an object over time.  Below are two examples where I show the trails of Comets Hayakutake and Hale-Bopp when they made their glorious appearance during spring of 1996 and 1997.