February 17, 2019

Viewing the Night Sky with Linux, Part II: Visit the Planets With XEphem - page 3

Quirky and Powerful

  • September 11, 2008
  • By Akkana Peck

Don't stop at the sky view; check out some of XEphem's other views. The Jupiter view shows you the position of the Great Red Spot and the four Galilean moons by number (right-click to find a moon's name), as well as their shadows when a moon's shadow falls on the planet. The Mars view is great for figuring out which part of Mars is pointing our way. You'll really appreciate that if you observe Jupiter or Mars with a telescope.

Tools->Night at a glance... is a handy table of which solar system objects will be visible throughout the night. XEphem also has some advanced features in the Tools menu that you can use to convert between coordinate systems, solve orbit equations and other useful calculations.

XEphem has been around a long time, and its user interface has some quirks. In particular, once you've changed anything important, like your Location, be sure to save it so XEphem will remember it next time: go to the control window's Preferences->Save... and click Save now.

To find objects outside our solar system, go back to the control window and use Data->Index. Type the object's name or designation and click on Sky Point. It's a bit picky about capitalization, though, and it's better at finding objects by catalog number than by name. You can add your own catalogs, of course. You can also download catalogs for comets, asteroids and artificial satellites in Data->Download. Anything you find in the Index window can be saved as a favorite so it will appear in the sky view's Favorites menu -- assuming you remember Preferences->Save.

Despite its quirks, XEphem is one of the most accurate and reliable planetarium programs available on any platform. Astronomers will appreciate its accuracy and its many useful views and tools.

Akkana Peck is a freelance programmer and writer and the author of Beginning GIMP: From Novice to Professional. �She's also a long-time amateur astronomer.

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