CELESTIA(1)

NAME
celestia - A real-time visual space simulation

SYNOPSIS
celestia [options]

DESCRIPTION
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.

OVERVIEW
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 Earth, 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.

USAGE
Mouse functions:

Left drag | orient camera
Right drag | orbit the selected object
Mouse wheel, |
Middle drag | adjust distance to selection
left click | select target, double click to center

Keyboard commands:

Navigation

H | Select the sun (Home)
C | Center on selected object
G | Goto selected object
F | Follow selected object
Y | Orbit the selected object at a rate synced to its rotation
ESC | Cancel motion

Free movement

HOME | Move closer to object
END | Move farther from object
F1 | Stop
F2 | Set velocity to 1 km/s
F3 | Set velocity to 1,000 km/s
F4 | Set velocity to 1,000,000 km/s
F5 | Set velocity to 1 AU/s
F6 | Set velocity to 1 ly/s
A | Increase velocity by 10x
Z | Decrease velocity by 10x
Q | Reverse direction
X | Set movement direction toward center of screen

Time

Space | stop time
L | Time 10x faster
K | Time 10x slower
J | Reverse time

Options

U | Toggle galaxy rendering
N | Toggle planet and moon labels
O | Toggle planet orbits
V | Toggle HUD Text
I | Toggle planet atmospheres (cloud textures)
W | Toggle wireframe mode
/ | Toggle constellation diagrams
 | Toggle constellation labels
; | Toggle earth-based equatorial coordinate sphere
B | Toggle star labels
P | Toggle 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
. | Widen field of view

Other

` | 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.

AUTHOR
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/