# Celestia

Celestia provides photo-realistic, real-time, three-dimensional viewing of the Solar System, the galaxy and the universe. It is an easy to use, freely-distributed, multi-platform, open source, software package which has become a valuable tool for astronomy education. Used in homes, schools, museums and planetariums around the world, it also is used as a visualization tool by space mission designers. Versions are available for computers running Windows, macOS, and Linux operating systems, with mobile (iOS and Android) versions recently released.
Although it is optimized for 3D astronomical visualization, Celestia can be used to display and explore other 3D environments, too.
And, for some reason, many people seem to find exploring with Celestia to be a lot of fun.

## About this guide

This Guide to Celestia is intended to be a comprehensive source of information for students, educators, and other users of Celestia. It includes instructions for obtaining, installing, using, customizing, and troubleshooting the Celestia software, as well as explanations of concepts and techniques from astronomy and computer graphics as needed to fully explore and understand Celestia and its universe. It is intended to address the needs of novice, casual, and advanced users.
The Guide to Celestia is very far from complete. You can help by adding useful content. Members of the Celestia community are encouraged to be bold in editing this WikiBook to provide the additions and corrections needed to make it useful for themselves and others. Please share your knowledge here.
Icons indicate approximate development status. Of course, all pages are subject to improvement at any time.

## Using Celestia

Currently, this section only contains basic explanations of how to use Celestia. If you would like more detail, please refer to Frank Gregorio's Celestia 1.6.1 User's Guide (also available as a PDF).
* Why Celestia?

### Getting Celestia to Run

* Download and Installation
* Graphics Hardware
* Display Options
* Render Paths
* Celestia's Command Line

### Exploring Celestia's Universe

* Getting Started: some usage examples
* Locations
* Navigation
** View Control
** Time Control
** Bookmarks (cel: URLs)
* Snapshots and Movies

### Understanding Celestia

* FAQs: Frequently Asked Questions
* Glossary of Celestia terminology
* Keyboard shortcuts

## Enhancing Celestia

The following reference pages will help you to add features and make Celestia easier to use in your environment.

### Scripting

* Scripting Overview
** Cel Scripting
** CelX Scripting
*** Introduction to CELX Scripting
*** CELX Lua Methods: a list of CELX functions
*** CELX Questions and Answers
**** Angles Between Two Objects
**** Assigning Keyboard Functions
*** CELX Development Suggestions: tips for improving your CELX/Lua scripts.

### Customizing Celestia

* Configuring Celestia: celestia.cfg
* Catalog Files: Defining new Objects
** SSC: Solar System Catalogs of Planets and their Satellites
** STC: STar Catalogs
** DSC: Deep Space Catalogs of Nebulae and Galaxies
** DAT: Binary Star Database
*** Star Database: information about the stars.dat file.
*** Catalog Cross References
* Positioning Objects: Flying through Time and Space
** Orbits & Trajectories
*** JPL Ephemerides
*** Reference Frames
*** Using SPICE with Celestia
** Rotation Models
** Scripting Positions (some implications of scripted methods)
* Keeping up Appearances
** Simple Add-Ons: Replacing Textures & Locating Catalogs
** Creating Textures: Painting Planets
** 3D Models: Sculpting Satellites
*** CMS models
*** CMOD models
* Specifying the Correct Time: TDB is not UTC
** Time Scales

### Development

* Development: Compiling Celestia for yourself
** Linux
** macOS
** Windows
** Qt4 Cross-platform GUI for Celestia v1.7+
* Development Road Map: Planned improvements and new features.
** Features being considered for v1.6.0
** 1.6.0 Changes for SSC/STC/DSC files
** 1.7.0 Changes: WIP list of changes in Celestia 1.7.0
* Versions: Major Celestia milestones.
* Bugs and Feature Requests
* Internationalization (Celestia i18n): Contributing to the translation of Celestia

## Addon Tutorials for Beginners

The following pages are for beginners. These are tutorials for creating different kinds of celestial bodies in Celestia.
* Tutorials: a few things you should know before making addons for Celestia.
1. Creating Solar System Objects
* Asteroids (basic): Adding simple asteroids to Celestia.
* Comets: Adding comets to Celestia.
* Asteroids (advanced): More advanced aspects of asteroid-making in Celestia.
* Moons: Adding natural satellites around objects in Celestia.
* Near-Earth Asteroids: Making asteroids whose orbits get perturbed in Celestia.
2. Creating Extrasolar Objects
* Stars: Adding stars to Celestia.
* Star Systems: Adding binary stars and multiple star systems to Celestia.
* Exoplanets: Adding exoplanets to Celestia.
3. Creating Deep-Sky Objects
* Galaxies: Adding galaxies to Celestia.
* Globulars: Adding globular clusters to Celestia.

## Credits

* Acknowledgements: Contributors to Celestia and to this WikiBook.

## External links
### Related Wikibooks

* A-level Physics/Cosmology
* Astrodynamics
* Astronomy
* Glossary of Astronomical Terms
* Solar System
* Wikijunior:Solar System
* Introduction to Astrophysics
* Transformative Applications in Education/Celestia
* The Universe Made Simple

### Celestia Web Sites

* https://celestiaproject.space/ - Home of Celestia
* https://github.com/CelestiaProject/Celestia - Celestia binaries and source code
* https://celestiaproject.space/forum/ - Celestia Discussion Forum
* https://www.classe.cornell.edu/~seb/celestia/ - Selden's List of Resources for Celestia
* https://de.wikipedia.org/wiki/Celestia - German wikipedia
* https://fr.wikipedia.org/wiki/Celestia - French wikipedia
* https://fr.wikibooks.org/wiki/Celestia - French WikiBook
* https://www.jcvignoli.com/celestia/wiki/index.php/Accueil - French Celestia Wiki
* http://celestia.albacete.org/ - Web page with a lot of activities (Spanish)

### Celestia Add-ons

Note: the Motherlode and Celestial Matters (both hosted on ibiblio.org) went offline on 2020 August 27. As of December 22 the Motherlode is back online, but Celestial Matters is still unavailable.
* List of addons on the Celestia Forum
* http://www.celestiamotherlode.net/ - The main add-ons repository (GitHub archive)
* http://www.celestialmatters.org/ - Celestial Matters web site: Celestia add-ons and other content of interest to Celestia users
* http://forum.celestialmatters.org/index.php - Celestial Matters forum
* https://www.jcvignoli.com/celestia/ - French repository of add-ons with eMule links --old
* http://www.celestiamotherlode.net/catalog/educational.php - A website containing detailed Celestia educational resources and journeys
* http://forum.celestialmatters.org/viewforum.php?f=6 - Celestial Matters - F-TexTools and refereed Add-ons

### Articles about Celestia

* http://www.linuxjournal.com/content/exploring-space-celestia - Linux Journal article Exploring Space with Celestia by Mike Diehl, July 15, 2008.
* http://www.linux-magazine.com/issue/58/Celestia_3D_Space_Simulation.pdf - Linux magazine article Touring the galaxy with Celestia STAR JOURNEY by Kristian Kissling, Issue 58, September, 2005.
* http://web.archive.org/web/20051224085847/http://www.esa.int/gsp/ACT/mission_analysis/designtool_overview.htm - ESA Advanced Concepts Team overview of design tools, 2005.
* http://discovermagazine.com/2004/nov/emerging-technology/ - Discover magazine article Emerging Technology by Steven Johnson, September, 2004.
* http://www.tiempolibresite.com/content/view/482/2/ - Interview of Chris Laurel by TiempoLibreSite