.\" Please adjust this date whenever revising the manpage.
.TH CELESTIA 1 "May 23, 2001"
.SH NAME
celestia \- A real-time visual space simulation
.SH SYNOPSIS
.B celestia
.RI [ options ]
.SH DESCRIPTION
This manual page documents briefly \fBcelestia\fP, 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.
.PP
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.
.SH 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 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.
.PP
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.
.\" Right click on the sun to bring up a menu of planets and
.\" other objects in the solar system.  After selecting a planet from the
.\" menu, hit G again to travel toward it.  Once there, hold down the right
.\" mouse button and drag to orbit the planet.
.SH USAGE
Mouse functions:
.PP
.TS
tab (@);
l l.
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
.TE
.PP
Keyboard commands:
.PP
Navigation
.PP
.TS
tab (@);
l l.
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
.TE
.PP
Free movement
.PP
.TS
tab (@);
l l.
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
.TE
.PP
Time
.PP
.TS
tab (@);
l l.
Space@stop time
L@Time 10x faster
K@Time 10x slower
J@Reverse time
.TE
.PP
Options
.PP
.TS
tab (@);
l l.
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
.TE
.PP
Other
.PP
.TS
tab (@);
l l.
`@Show frames rendered per second
.TE
.PP
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.
.SH 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 http://celestiaproject.space/
