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celestia-gtk - Man Page

A real-time visual space simulation


celestia [options]


This manual page documents briefly celestia, a 3D space simulator. Celestia is a real-time visual simulation of space in our local region of the universe. Choose a point within about 1000 light years of Earth, and Celestia will show you an approximation of how it would appear to your eyes were you actually there. Some of what Celestia shows is necessarily hypothetical--the farther away from Earth you get, the less real data there is and the more guesswork is involved.  Thus Celestia supplements observational data with good guesses based on models of stellar and planetary processes.

Celestia is unique in its ability to allow you to navigate at an immense range of scales.  Orbit a couple kilometers above the surface of a tiny, irregular asteroid, then head off toward Jupiter, watching it grow from a bright point of light into a looming sphere filling your field of vision.  Leave our solar system entirely and observe the sun as it fades from a brilliant disk to a bright star, disappearing almost entirely as you head off toward the Upsilon Andromeda system to orbit around its innermost giant planet.


Celestia will start up in a window, display a welcome message and some information about your target (top left corner), your speed, and the current time (Universal Time, so it'll probably be a few hours off from your computer's clock.)  In Celestia, you'll generally have an object selected; currently, it's Eros, but it could also be a star, planet, spacecraft, or galaxy.  The simplest way to select an object is to click on it.  Try clicking on a star to select it.  Right drag the mouse to orbit arround the selected target.  Left dragging the mouse changes your orientation too, but the camera rotates about its center instead of rotating around the target.  Rolling the mouse wheel will change your distance to the space station--you can move light years away, then roll the wheel in the opposite direction to get back to your starting location.  If your mouse lacks a wheel, you can use the Home and End keys instead.

Press G and you'll zoom through space toward the selected star.  If you press G again, you'll approach the star even closer.  Press H to select our Sun, and then G to go back to our solar system.  You'll find yourself half a light year away from the Sun, which looks merely like a bright star at this range.  Press G three more times to get within about 30 AU of the Sun and you will be to see a few planets become visible near the Sun.


Mouse functions:

Left dragorient camera
Right dragorbit the selected object
Mouse wheel,
Middle dragadjust distance to selection
left clickselect target, double click to center

Keyboard commands:


HSelect the sun (Home)
CCenter on selected object
GGoto selected object
FFollow selected object
YOrbit the selected object at a rate synced to its rotation
ESCCancel motion

Free movement

HOMEMove closer to object
ENDMove farther from object
F2Set velocity to 1 km/s
F3Set velocity to 1,000 km/s
F4Set velocity to 1,000,000 km/s
F5Set velocity to 1 AU/s
F6Set velocity to 1 ly/s
AIncrease velocity by 10x
ZDecrease velocity by 10x
QReverse direction
XSet movement direction toward center of screen


Spacestop time
LTime 10x faster
KTime 10x slower
JReverse time


UToggle galaxy rendering
NToggle planet and moon labels
OToggle planet orbits
VToggle HUD Text
IToggle planet atmospheres (cloud textures)
WToggle wireframe mode
/Toggle constellation diagrams
= Toggle constellation labels
;Toggle earth-based equatorial coordinate sphere
BToggle star labels
PToggle per-pixel lighting (if supported)
[Decrease limiting magnitude (fewer stars visible)
]Increase limiting magnitude (more stars visible)
{Decrease ambient illumination
}Increase ambient illumination
,Narrow field of view


`Show frames rendered per second

It's possible to choose a star or planet by name:  press Enter and type in the name, and pressing Enter again.  You can use common names, or Bayer designations and HD catalog numbers for stars.  Bayer and Flamsteed designations need to be entered like "Upsilon And" and "51 Peg".  The constellation must be given as a three letter abbreviation and the full Greek letter name spelled out.  HD catalog numbers must be entered with a space between HD and the number.


Celestia has been written by Chris Laurel <claurel@gmail.com> and it's available under the terms and conditions of the GNU General Public License from https://celestiaproject.space/


May 23, 2001