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 XEphem(1X)                                                       XEphem(1X)

      XEphem - an interactive astronomical ephemeris for X

      xephem [-prfb] [-install {yes|no|guess}]

      XEphem is an interactive astronomical ephemeris program for X Windows
      systems with Motif. It provides many graphical views as well as
      quantitative heliocentric, geocentric and topocentric information for
      Earth satellites, solar system and celestial objects.

      XEphem contains extensive context-sensitive on-line help. Virtually
      none of that help is duplicated here so go ahead and run XEphem to
      learn more.

      The Main window of XEphem provides control and display of three basic
      services: observing circumstances, looping, and access to additional
      tools and displays. Observing circumstances includes location, date,
      time and atmospheric conditions (used for the refraction model).
      Looping refers to the ability to set up XEphem so that it
      automatically increments time at a desired step size and rate.
      Additional displays provide all of the graphical and quantitative
      information available, and always refer to the circumstances defined
      in the main menu. Tools provide access to plotting, searching, AAVSO,
      Seti@Home and more.

      -prfb displays all the built-in default resources, then exits.

      -install controls whether XEphem will install a private colormap.
      Without this option XEphem will try to decide automatically whether it
      is necessary. To force using a private colormap, use -install yes; to
      prevent it use -install no. The default automatic behavior is
      equivalent to -install guess.

 Menu Tour

      This menu controls basic operation, including exiting. When XEphem is
      first started it may beep. This means a message has been put in the
      messages dialog, which can be displayed from this menu. Other chores
      here include setting up network access; a simple progress meter;
      controlling time and location information remotely.


      This menu offers several graphical displays if the Earth, Moon and
      several planets; a user configurable table displaying; and Sky and

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 XEphem(1X)                                                       XEphem(1X)

      Solar System views.


      This menu gives access to tools which can plot any XEphem data items;
      save any data items to text files for easy export to other programs;
      enter an arbitrary function to evaluate and solve using any XEphem
      data items; access AAVSO online; monitor your Seti@Home client; show
      the Night at a glance; and find close pairs of objects.


      This menu gives control over which objects XEphem will work with.
      Objects may be created on the fly, read from catalog files, deleted or
      searched. A special category of objects known as Field Stars may be
      configured, which are very large catalogs of objects whose access has
      been optimized. Up to three User objects may be assigned for
      especially easy access in several other places throughout XEphem. Also
      here is a tool which can update Earth satellite orbital elements from
      the web.


      This menu offers several configuration choices. These will effect the
      overall appearance or behavior of XEphem. These choices, as well as
      fonts and colors, can be changed at runtime and saved to disk to
      become the new defaults.


      This menu offers overall information about B .XEphem; context
      sensitive help; several worked examples; references; version number
      and the Copyright statement.

 X Resources
      XEphem initial conditions are defined using a resource file. By
      default the file is named XEphem located in a directory also called
      XEphem in your $HOME directory. You will want to tune some of these to
      your taste and circumstances; most may be left unchanged.

 Time zones
      XEphem will attempt to obtain time zone information from the host
      operating system.  If this fails for some reason, time zone offset and
      name may also be set manually at any time from the Main menu.

      Elwood Downey, email

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 XEphem(1X)                                                       XEphem(1X)

      The latest information about XEphem is maintained at

      The online Help entry on Credits lists many of the references,
      individuals and organizations which have contributed to XEphem.

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