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 xsky(1X)                                                           xsky(1X)
                                 25 May 1993

      xsky - a computerized star atlas for X

      xsky [-toolkitoption ...] [-LbcmfgspOBAFGKM ...]

      Xsky is a computerized star atlas running under the X11 window system.
      It allows interactive viewing of the sky and construction of star
      charts which may be printed on any PostScript printer.

      The sky is displayed with north straight up and oriented as seen by
      the naked eye.  Stars are sized according to their apparent magnitude
      and their colors correspond to the spectral class, as given by the
      relevant catalog.

      Non-stellar objects are depicted as circles, boxes, and ellipses.
      Objects from the quasar catalog are circles; objects from the RNGC
      catalog are elliptical if galaxies, circular if clusters, and boxes if

      Xsky uses Athena widgets and the X toolkit exclusively, so it should
      run on any X platform.  This also means that most of the familiar X
      command line options should work, although xsky does like to pick its
      own fonts for object identification text.

      Environment variables control the location of the catalog data files
      and the binary dump files created by xsky.  These binary dump files
      are the in-core databases that xsky creates for each catalog.  If this
      file exists for any catalog, it will be read in place of building the
      binary database for that catalog.  If the file exists with a size of
      zero, the catalog will be read, and the binary database will be built
      and dumped to the file for use by later invocations of xsky.

      Xsky accepts all of the standard X Toolkit command line options as
      well as the following:

      -h      Print a very terse (in all actuality useless) usage message.

      -L      Start with a large display.  After positioning the small
              outline on the screen, xsky resizes to fill the entire screen.

      -b      Draw the sky in black-and-white mode even if this is a color
              display.  The background remains black, but stars are white
              instead of colored.

      -c catlist
              Set the initial list of displayed catalogs to catlist.  This
              is a comma-delimited list, with each catalog being specified
              by its menu name in the catalog selection menu.

                                    - 1 -           Formatted:  July 7, 2022

 xsky(1X)                                                           xsky(1X)
                                 25 May 1993

      -m mag  Set the initial limiting magnitude to mag.  Stars dimmer than
              this will not be displayed.

      -f font Set the font for object identification to font.  This font is
              used for object names which are not Greek letters.

      -g font Set the font for Greek letters to font.  This font is used for
              Bayer designations of stars from the Yale Bright Star Catalog.

      -s scale
              Set the initial display scale to scale pixels per degree.

      -p position
              Set the initial position of the display to position.  This is
              a string in the format <nnh hhm nns.nnn, +/-nnd nn' nn".nn>
              specifying the right ascension and declination of the display

      -OBAFGKM color
              Each of these option letters represents a stellar spectral
              class.  Specifying one of these options changes the color of
              the stars in that spectral class to color.  Stars of class W
              are represented as O, and stars of classes C, R, N, and S are
              represented as M.  Unknown or undecipherable spectral classes
              are rendered as white.

      -bin    Terminate after reading the text catalogs and building the
              binary databases.  All contact with the X Window System is
              avoided; this option allows building the binary databases from
              an ordinary terminal.  This option must be used alone; it will
              not work (nor does it make sense) with any other options.

      Info    Brings up a panel showing the size and grid spacing of the
              display.  There are also two text boxes containing information
              which may be edited to change the values of magnitude limit
              (for stars) and display scale.

              Brings up a menu which allows selection of the catalogs to be

      Zoom In Increases the magnification of the display.  Each zoom step
              increases the display scale by 20%.

      Zoom Out
              Decreases the magnification of the display.  Each zoom step
              decreases the display scale by 20%.

      Grid    Draws lines of right ascension and declination on the sky
              display.  The "Info" display gives the spacing of the lines.

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 xsky(1X)                                                           xsky(1X)
                                 25 May 1993

              The lines are unlabelled, but the spacing and display center
              will allow determination of the line coordinates.

      Hide IDs
              Removes all object identifications from the display.  They may
              be recalled by toggling "Hide IDs" again.  IDs are created by
              clicking the center mouse button on an object; see below.

      Erase IDs
              Erases all object identifications from the display.  Once
              erased, identifications may not be recalled.

      Find    Brings up a panel with a text widget into which the name or
              designation of an object may be edited.  Clicking the Find
              button on the panel will then cause the display to be moved to
              that object if it can be identified by the given name or
              designation.  At present, only stars can be located by name.
              The file "catalogs.doc" documents the object designations that
              can be entered on the Find panel.

      Chart   Writes a file called "" which may be printed on
              any PostScript printer for an exact representation of the
              current sky display, including identifying text and grid

      Quit    Leave xsky.

      The following interactions allow manipulation of the sky display.
      Note that the mouse cursor is the original Starship Enterprise, flying
      toward the top of the screen.  The forward tip of the Enterprise's
      "saucer section" is the cursor hotspot.

      +    The horizontal scrollbar at the bottom of the sky display scrolls
           the sky due east/west.

      +    The vertical scrollbar at the right of the sky display scrolls
           the sky due north/south.

      +    Clicking the left mouse button on a displayed object brings up
           the catalog information for that object.

      +    Clicking and holding the center mouse button on a displayed
           object brings up an outline box which follows the mouse;
           releasing the center button replaces the box with identifying
           text placed at that location.

      +    Clicking the center mouse button with the Shift key depressed
           removes the identifying text under the mouse pointer.

                                    - 3 -           Formatted:  July 7, 2022

 xsky(1X)                                                           xsky(1X)
                                 25 May 1993

      +    Clicking the right mouse button on any point in the sky display
           recenters the display on that point.

      The "Display center" at the top of the main display is an editable
      text buffer.  To move to a known location on the sky, simply edit this
      buffer to contain the desired right ascension and declination,
      following the general format shown in the buffer.  Hitting the return
      key while in the buffer causes the sky display to be updated.

                The Yale Catalog of Bright Stars

                A dump of the binary in-core database for the YBS catalog

                The Revised New General Catalog of Non-Stellar Objects

                RNGC catalog description abbreviations

                A dump of the binary in-core database for the RNGC catalog

                The Revised Optical Catalog of Quasi-Stellar Objects

                A dump of the binary in-core database for the QSO catalog

                Common star names by HR number for use with the YBS

      The file xskyenv defines a number of other environment variables for
      additional catalogs supported by, but not shipped with, xsky.

      The -L option does not work except as a work procedure, and work
      procedures are turned off.

      Terry R. Friedrichsen, Sunquest Information Systems.

      The precession algorithm and precession constants are from
      PRECESS.BAS, written by PC Leyland.

                                    - 4 -           Formatted:  July 7, 2022

 xsky(1X)                                                           xsky(1X)
                                 25 May 1993

      Brian Wing greatly sped up the screening of objects to determine
      whether they fall in the current display.

      Jim Sharpe was the original beta tester, making many useful
      suggestions and improving the user interface.

      The supplied object databases are stripped-down versions of databases
      supplied by the National Space Sciences Data Center (NSSDC) at the
      Goddard Spaceflight Center in Greenbelt, Maryland, which is
      administered by the National Aeronautics and Space Administration

                                    - 5 -           Formatted:  July 7, 2022