index.docbook

celestia源代码

our universe in three dimensions. Unlike most planetarium software,
&celestia; does not confine you to the surface of the Earth. You can travel
throughout the solar system, to any of over 100,000 stars, or even beyond
the galaxy. All travel in &celestia; is seamless; the exponential zoom
feature lets you explore space across a huge range of scales, from galaxy
clusters down to spacecraft only a few meters across. A 'point-and-goto'
interface makes it simple to navigate through the universe to the object
you want to visit. Many add-ons and vastly improved textures of high
resolution are available for &celestia;.
</para>
</abstract>

<keywordset>
<keyword>KDE</keyword>
<keyword>Celestia</keyword>
<keyword>Astronomy</keyword>
<keyword>OpenGL</keyword>
<keyword>Simulation</keyword>
</keywordset>

</bookinfo>

<chapter id="introduction">
<title>Introduction</title>
<para>
Many of us have looked up at the stars on a dark night and wondered what it would be like to launch ourselves into space and soar among the stars.  What do the astronauts of the space shuttle really see when they look down upon our beautiful Earth turning slowly below?  What wonders might we encounter if we could really visit Saturn and journey right through its rings?  What might they actually look like up close?  If you have ever wondered about these things and would like to find out the answers, we of the &celestia; community are happy to introduce you to &celestia;!
</para>

<para>
&celestia; is a free real-time space simulation that lets you visually experience our universe in three dimensions.  &celestia; was the initial inspiration and creation of Mr. Chris Laurel, a Seattle, WA computer programmer who in 2001, decided to write a free software program to be made available to everyone on the internet that would place you in control of a virtual reality world of the solar system.  His vision and dedication gave birth to a program that is unlike any other planetarium program in existence.  &celestia; doesn't confine you to the surface of the Earth as many other programs do.  Instead, Chris created a capability to travel throughout the solar system and anywhere else in space, at any speed and in any direction you choose.  If you wish, you can fly via your own <quote>hyperdrive</quote> spacecraft to visit stars circling the center of the Milky Way beyond the confines of our Sun.  You can even travel completely out of the Milky Way galaxy and view it from far space.
</para>

<para>
When &celestia; version 1.0 first appeared available for download on the Internet, space enthusiasts all over the world discovered and quickly realized the potential of this beautiful program.  Within a year, many talented people worldwide joined Chris in a collaborative volunteer effort to make &celestia; into not only a good graphical space simulation program but into a great one, capable of producing a virtual world of space rivaling the visual quality seen only in Hollywood films.
</para>

<para>
They have succeeded.  As of this writing, over 1000 members of the public are part of the &celestia; forum community.  Over 2 million people have downloaded the program for use at home or school.  The list grows daily and includes talented graphic artists, computer programmers, astronomers, astrophysicists, animators, engineers, teachers, students, professionals from scores of occupations and ordinary citizens in over 22 countries around the world.  We invite you to join the &celestia; <ulink url="http://www.shatters.net/forum/profile.php?mode=register">forum</ulink>.
</para>

<para>
&celestia; is available free of charge for Windows, Linux, and Mac OS X from <ulink url="http://www.shatters.net/celestia/download.html">http://www.shatters.net/celestia/download.html</ulink>.  Hopefully, you've already downloaded &celestia; and are really to install it and experience the beauty of space.  Here is just a taste of what you will be able to encounter:
</para>

<itemizedlist>
<listitem><para>Hover over each of the nine planets in our solar system as they rotate slowly below you.  See clouds actually drift by (where applicable).  Look carefully and you may be able to see mountains, canyons and craters on the planet surfaces with shadows being cast by them as the Sun sets low on the horizon.
</para></listitem>

<listitem><para>Take a spin down to the Earth's surface at a lazy speed or at thousands of miles/km per hour in your own spacecraft.  Skim over the oceans of Earth as you actually fly below the clouds.  See the sky turn a pale blue and eventually, transform into the crimson color of a Sunset.  Soar back into space in time to see the lights come on in the cities of Earth and glow an eerie white as the dark side of Earth turns below you.
</para></listitem>

<listitem><para>Position yourself above the giant gas world of Jupiter and watch as its large moons drift across the face of the planet, casting eclipse shadows on its banded clouds and Great Red Spot.
</para></listitem>

<listitem><para>Hover far beyond Saturn, speed up time and count its many moons revolving around its magnificent ringed body like pearls swirling on an invisible necklace.
</para></listitem>

<listitem><para>Journey to the frozen wasteland of Pluto and its moon Charon and imagine their icy coldness as the Sun's faint light casts pale shadows across their cratered ice surfaces.
</para></listitem>

<listitem><para>Take up station behind the comet Halley, set Celestia's clock back in time and follow this famous comet on a trip into the inner solar system, sailing past Earth with its gaseous blue tail streaming out behind it.
</para></listitem>

<listitem><para>Set your spacecraft speed and journey from the Earth's surface up to the International Space Station or the Hubble Space Telescope.  Test your skill rendezvousing with them as they orbit Earth every 90 minutes.
</para></listitem>

<listitem><para>Fly out to the very edges of our solar system, locate and follow behind Voyager 1 and 2 as they speed farther and farther away from their creators back on Earth, headed on a one way journey through the blackness of frigid space toward distant stars that will take them millions of years to reach.
</para></listitem>

<listitem><para>Set your ship at faster-than-light speed and sail to Rigel Kentaurus A and B, located 4.5 light years from Earth.  See if you can find their tiny red dwarf companion Proxima Centauri, the closest star to our own Sun, or choose to observe rotating Sunspots on any of a whopping 2,000,000 other stars drawn by your computer in the Celestia universe (to see all of those stars, a separate add-on is required).
</para></listitem>

<listitem><para>Download some of the many stunning add-ons available for Celestia and your experience becomes filled with even more wonders.  Visit the Discovery, a spaceship from the film "2001, a Space Odyssey", dark, abandoned and adrift somewhere in Jupiter space with the HAL computer inside.
</para></listitem>

<listitem><para>Journey to the edges of a massive rotating Black Hole as it spins near its stellar companion.
</para></listitem>

<listitem><para>Track the spacecraft Cassini as it approaches a precise rendezvous with Saturn in 2004.
</para></listitem>

<listitem><para>Journey to Earth?s future and be witness to the end of our planet as a swollen Red Giant sun consumes it.
</para></listitem>

<listitem><para>Witness a pulsar imbedded deep in the Crab Nebula spinning rapidly as it sends its twin beacons of light through the nebula gas.
</para></listitem>

<listitem><para>Travel back in time to witness a re-creation of what the Earth looked like billions of years ago.  Be there as Orpheus, a planet the size of Mars crashes into it, creating our Moon and sending it into an orbit within a few thousand miles of Earth.
</para></listitem>

<listitem><para>Travel forward to the year 2900 CE to observe giant mirrors melt the Martian polar ice caps and help to terraform the planet into a verdant world of water, plants and cities of the future.
</para></listitem>

<listitem><para>Drop "up" to the massive rotating Space Station V from the film, "2001 a Space Odyssey" in the year 2400 CE and see if you can land your "Celestia 1" spaceship in its cavernous landing bay.
</para></listitem>

<listitem><para>Instantly change the appearance and detail of planets and moons using the Alternative Textures command.
</para></listitem>

<listitem><para>Are you a Star Wars fan?  The &celestia; community has made available for download an entire Star Wars solar system.  Orbit the planet Tatooine and you will be amazed at the realism of its arid deserts.  Fly via hyperjump over the ice world, Hoth or to the green world of Endor but be careful for tractor beams.  Somewhere in that solar system will be the giant imperial Deathstar, glinting as the light from the system?s yellow Sun actually reflects off its evil metallic skin as imperial tie fighters keep guard.
</para></listitem>

<listitem><para>Approach an entire fleet of Borg Cubes as you command the USS Enterprise E from the StarTrek series.
</para></listitem>

</itemizedlist>

<para>
These are just a few of &celestia;'s features.  Each week, new features are being added by &celestia;'s programmers and other talented contributors.  It is a program undergoing a rapid evolution in computer graphics.  Add-on features, for example, will include entirely new solar systems with dozens of planets and moons drawn in vivid detail, gaseous nebula clouds, new galaxies, stars, globular clusters and spacecraft both real and imaginary.  Periodically as new features are added, this User's Guide will also be revised.  If this list above excites you, let's get started on our journey into the heart of &celestia;.
</para>

</chapter>

<chapter id="solar_system_tutorial">
<title>Solar System Tutorial</title>
<para>
&celestia; is a stunning program to observe and explore the solar system.  To help you discover some of its beauty and secrets, &celestia; has a short journey already laid out for you.  To see it, launch the program as described below, pull down the <guimenu>Help</guimenu> Menu and select <guimenuitem>Run Demo</guimenuitem>.  &celestia; developers have also created a score of detailed Celestia Educational Activities to take Celestia users on a virtual tour of the universe.  Look for them on the Celestia website.
</para>
</chapter>

<chapter id="what_is_available">
<title>What is Available</title>

<para>
&celestia; is a computer program written in the computer language C++.  The code is Open Source, and may be examined and freely modified by anyone under the terms of the GNU Public License.  For experienced programmers who have an interest in improving the program, you can find the Celestia source code at <ulink url="http://www.SourceForge.net">http://www.SourceForge.net</ulink>
</para><para>
In addition to the actual program, &celestia; includes many other add-on files (graphics and data) that the program can use.  If you choose to download the entire library of over 250 &celestia; add-on files designed to date by its many contributors, they can take up over 3 GB (gigabytes) of disc space.  For many people with limited computer memory and/or internet download speed, that is very large.  To offer &celestia; in a reasonable fashion, therefore, the basic program is provided for download with a comprehensive but limited set of files, sufficient to experience its capabilities without overtaxing your computer.  "Links" (web addresses) to guide you to the additional add-on files available are listed on the web within the User?s forum and &celestia; website.  To fully experience what &celestia; has to offer, we urge you to seek out and download some of these other add-on files.  Unfortunately, the add-ons are spread out across over 50 websites.  Eventually, we will have a central repository for most of them, but that is still in the works.  If you would like to get started, however, you can visit these links:
</para>

<itemizedlist>
<listitem><para><ulink url="http://shatters.net/forum/index.php">Celestia add-on page</ulink></para></listitem>
<listitem><para><ulink url="http://mikecelestia.bravehost.com/downloadlist.htm">Mike's add-on list</ulink></para></listitem>
<listitem><para><ulink url="http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/celestia/celestia/textures/">Celestia basic textures</ulink></para></listitem>
<listitem><para><ulink url="http://ennui.shatters.net/celestia/files/?M=D">Celestia files</ulink></para></listitem>
<listitem><para><ulink url="http://www.celestialvisions.net/">Celestial Visions</ulink></para></listitem>
<listitem><para><ulink url="http://homepage.eircom.net/~jackcelestia/">Jack's spacecraft add-ons</ulink></para></listitem>
<listitem><para><ulink url="http://www.lns.cornell.edu/~seb/celestia/index.html">Selden's Resources</ulink></para></listitem>
<listitem><para><ulink url="http://www.shatters.net/~t00fri/texfoundry.php4">Texture Foundry</ulink></para></listitem>
<listitem><para><ulink url="http://www.shatters.net/~praesepe/files/">Praesepe's Files</ulink></para></listitem>
<listitem><para><ulink url="http://www.bt.homepage.btinternet.co.uk/Celestia.htm">BT's Celestia add-ons</ulink></para></listitem>
<listitem><para><ulink url="">Don's Celestia Hub</ulink></para></listitem>
<listitem><para><ulink url="http://exp.arc.nasa.gov/downloads/celestia/extras/">NASA Learning Technologies &celestia; distribution</ulink></para></listitem>
<listitem><para><ulink url="http://63.224.48.65/~impulse/Hub/Celestia_Hub.html">Frank's Add-ons</ulink></para></listitem>
<listitem><para><ulink url="http://www.fsgregs.org/celestia/">Jim's Celestia page</ulink></para></listitem>
<listitem><para><ulink url="http://68.43.175.239/JohnsCelestiaPage/modules/mydownloads/">John's Celestia page</ulink></para></listitem>
</itemizedlist>

<note><para>Please note that the above links may be temporary.  Websites come and go based on member's arrangements with hosting servers.  However, the above sites will get you started.  If I left out someone's add-on website, please forgive me.  Remember that there are over 50 such sites scattered throughout the forum.  To see links to more of them, visit and browse <ulink url="http://shatters.net/forum/index.php">the forum</ulink>.</para></note>

<para>
The &celestia; package for computers running <trademark class="registered">Microsoft Windows</trademark> 95, 98, ME, 2000, XP, or NT 4.0 is offered as a fully "executable" program.  It will install itself into your computer.  The current Windows version is 11 megabytes in size and is called &celestia;-win32-1.3.1.exe.  It is available for download at <ulink url="http://www.shatters.net/celestia/download.html">http://www.shatters.net/celestia/download.html</ulink>.  If you have a computer that is less than 3 years old, this is the only file you will need to get started.  If you have an older computer, or one with a graphics card with less than 16 megabytes (MB) of memory (see below), the &celestia; package with low-resolution textures is only 4.5 MB in size and may run better on your system.  You can find it at the same website above.  Please note that you do not need both of them.  See hardware comments in the next section below for more detail.
</para><para>
&celestia; is also available to Apple Macintosh users running MacOS X (&celestia; version 1.2.5).  The comments mentioned above for Windows also apply to the Apple version of &celestia;.
</para><para>
&celestia; is available for Linux in three different versions.  All of them are available in a single tarred, gzipped source archive at <ulink url="http://www.shatters.net/celestia/download.html">http://www.shatters.net/celestia/download.html</ulink>.  Which version you choose to install depends upon which desktop environment you have installed.  The most polished version of &celestia; for Linux requires KDE3 (&celestia; is not compatible with earlier versions of KDE.)  If you do have KDE3, it's highly recommended that you choose the KDE version of &celestia;, as it's under the most active development.  &celestia; can also be compiled to use Gnome/Gtk, although Gnome interface is not up to par with KDE and Windows UI.  It's still possible to build &celestia; even if you don't have either KDE3 or Gnome.  The third version of &celestia; is the GLUT version.  GLUT is a cross platform framework for OpenGL applications that should be installed on nearly every Linux computer with OpenGL.  However, it provides only a bare minimum of GUI features; if you use the GLUT version of &celestia;, you will be missing the helpful menus and dialog boxes of the other versions.
</para>

<important>
<title>Required Libraries</title>
<para>
All versions of &celestia; for Linux require that you have OpenGL installed.  More and more distributions are shipping with OpenGL, so if you've recently installed or re-installed Linux, there's a good chance that you already have a working OpenGL configuration.  In order to build &celestia;, you need to have the OpenGL developers packages installed.  They should be available on your distribution CD or ftp site if they're not already installed.  After you've successfully built &celestia;, you will want to be able to run it with hardware 3D acceleration.  For this, you'll need a Linux OpenGL driver from your graphics chipset maker.  If it's not already installed, you'll have to download it from the chipset maker's web site.  NVIDIA and ATI are the two largest graphics hardware makers, and both offer Linux drivers in the drivers section of their web sites.  &celestia; requires the image format libraries libjpeg and libpng; both should be present on all up to date Linux installations.  In order to build the Gnome/Gtk version of &celestia;, the gtkglarea library is necessary.  It is available at <ulink url="http://www.student.oulu.fi/~jlof/gtkglarea/">http://www.student.oulu.fi/~jlof/gtkglarea/</ulink> if not already installed on your computer.
</para>
</important>
</chapter>


<chapter id="hardware_requirements">
<title>Hardware Requirements</title>
<para>
&celestia; is a sophisticated program that not only positions and graphically depicts the complete solar system in 3D; it also plots and tracks a sky full of hundreds of thousands of stars in real time.  This takes computer power and computer memory.  &celestia; also has available scores of add-on files.  Some of them are large graphics files that require lots of RAM memory.  Thus, identifying what level of computer performance you need to enjoy the program depends upon what level of detail you wish to achieve.
</para><para>