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Notes on Celestia

(The above look best in the Print Preview of the Opera web browser.)

Warning: Do Not Print

I wouldn't recommend printing this exact page - since it's formatted for display on screen, not printing.

Firstly, there's clutter in the form of the navigational header, footer, and the ads. And, judging by the Print Preview in Internet Explorer, the tables might not come out in a very organized way. And plus, there's a background image, the text colors are not really suitable for printing, and the black background for the table headers might waste lots of ink.

You might have better luck with the possibly printable version, which at least looks decent in the Print Preview in the Opera web browser, but not Internet Explorer.

There's also a possibly printable version which has only the tables detailing the controls, Controls for Celestia. It also definitely looks best in the Print Preview of the Opera web browser.

Controls for Celestia

Number pad (with Num Lock turned on)
Roll ship
(makes everything on the
screen roll clockwise
moves camera downward
(pitch down)
Roll ship clockwise
(makes everything
on the screen roll
Moves camera left
(yaw left)
Stops camera drifting
(stop rotation)
Moves camera right
(yaw right)
moves camera upward
(pitch up)

Motion (spaceflight)
AIncrease velocitySStopZDecrease velocity
QReverse directionXSet movement direction toward center of screen
F1StopF2Set velocity to 1 km/s F3Set velocity to 1,000 km/s
F4Set velocity to speed of light F5Set velocity to 10x the speed of light. F6Set velocity to 1 AU/s
F7Set velocity to 1 ly/s

Object labels
WAsteroids & cometsBStars
MMoonsNSpacecraft &Locations

=Toggle constellation labels /Toggle constellation diagrams Ctrl+BToggle constellation boundaries

PToggle planet labels OToggle planet orbits;Show an earth-based equatorial coordinate sphere

Ctrl+PMark selected objectCtrl+K Toggle display of markers

LTime 10x faster
KTime 10x slower
JReverse time
\Real time rate
SpaceStop and unstop time
!Set time to now
F10Capture image to file
Ctrl+C, Ctrl+INSCopy location URL to clipboard
DRun demo
F8Enable joystick
Ctrl+VCycle between supported OpenGL render paths

Informational commands
VToggle verbosity of info text
?Display light-travel delay between observer and selected object
`Show frames rendered per second

Ctrl+RSplit view vertically
Ctrl+USplit view horizontally
TABCycle active view
DELDelete active view
Ctrl+DDelete all views except active one

Mouse functions
Left dragOrient camera.
Right drag"Orbits" the selected object - allows you to kind of roll it around the screen
Wheel, Right + Left drag, or Ctrl + Left dragadjust distance to selection
Shift + Left dragchange field of view (e.g. => telescopic view)
Wheel (middle button) clicktoggle field of view between 45 degrees and the previous field (e.g. telescopic view)
Left-clickselect object
Left double clickcenter selection
Right-clickbring up context menu

View and navigational
EnterBring up a prompt so you can type in the name of an object to select.
BackspaceCancel currently selected object. If the currently selected object orbits another object, the orbited object will be selected.
HSelect Sol
GGo to selected object
CCenter view on selected object
FFollow selected object
YOrbit the selected object at a rate synced to its rotation
"Chase selected object (orientation is based on selection's velocity)
:Lock on selected object
TTrack selected object (keep selected object centered in view)
Shift+ArrowsOrbit object
ESCCancel motion (including G, go), or script. Cancels tracking, following or sync orbiting of objects.
HOMEMove closer to object you have selected; the quickest, most no-nonsense way to get to something.
ENDOpposite of HOME; moves farther from selected object
1-9Select planets around nearby sun
Shift+CCenter/orbit--center the selected object without changing the position of the reference object. A very neat way to move around and shift your view of things - I'm not quite sure how it works, but it seems like you might have to be sync orbiting, following, or chasing an object, or have a lock on on object or pair of objects.
*Switch to rear view when pressed the first time, and and back again when pressed the second time. Not recommended unless you switch back right away, since the camera will no longer be facing in the direction you're moving in, which could be confusing.

Important commands for realism
-Subtract light-travel delay from current simulation time
+Switch between artistic and limit of knowledge planet textures
rLower texture resolution
RRaise texture resolution
Ctrl-AToggles atmospheres on or off, for all planets and moons that have them.
IToggles cloud textures
UToggle galaxy rendering
Ctrl+EToggle eclipse shadow rendering
Ctrl+LToggle night side planet maps (light pollution)
Ctrl+SCycle the star style between fuzzy discs, points, and scaled discs
Ctrl+TToggle rendering of comet tails
Ctrl+WToggle wireframe mode
Ctrl-YToggle Auto Magnitude mode, auto adaptation of star visibility when you change your field of view
Ctrl+XToggle antialias lines (makes lines look sharper or more smooth)
[If autoMag OFF: Decrease limiting magnitude (fewer stars visible)
If autoMag ON: Decrease limiting magnitude at 45 deg field of view
]If autoMag OFF: Increase limiting magnitude (more stars visible)
If autoMag ON: Increase limiting magnitude at 45 deg field of view
{Decrease ambient illumination
}Increase ambient illumination
,Narrow field of view
.Widen field of view

The farthest objects visible with the naked eye

According to http://www.wonderquest.com/naked-eye.htm, "The farthest star that we can see under the best of conditions is probably about 4,075 light years away."

So, for realism, you can go to the Render menu, select View Options, and use the little sliding bar underneath "Filter Stars" to filter stars by their distance in light years.

According to http://celestia.teyssier.org/doc/opt_stars_visible.html:

"On the surface of Earth, our view generally includes stars of an apparent magnitude of +6.5 or less (the lower the number, the brighter the star). Setting this option to Magnitude 6.5 - 7.5 results is a realistic sky as seen from Earth on a clear night, with only about 3,000 stars visible."

According to http://www.guinnessworldrecords.com/content_pages/record.asp?recordid=45851:

"The remotest heavenly body visible with the naked eye is the Great Galaxy in the constellation of Andromeda. A silver smudge in the sky gives the Andromeda Galaxy away - at a mind-boggling 2,200,000 light years from Earth, anyone can spot it! One of the closest galaxies to our own, the light we see is the result of 200,000,000,000 stars shining together. The spiral galaxy is said to have been discovered by German astronomer, Simon Marius, around 1611."

How to make any location on Earth be labeled in Celestia

You can have any location on Earth be labeled in Celestia by opening the file world-capitals.ssc in the Data folder using a text editor, and adding something like the following:

Location "Hubbard, OH" "Sol/Earth"
LongLat [ -80.5666 41.1 0 ]
Importance 1000
Type "City"
Hubbard, Ohio is located at 80:34W, 41:06N. It has a western longitude, which means in Celestia the 80 should be -80. (Southern latitudes are also negative numbers).

To get the .5666 in the -80.5666, you have to divide the 34 (in 80:34W) by 60. To get the .1 in the 41.1, you have to divide 6 (in 41:06N) by 60.

To go to any location on Earth

First, I suggest sync-orbiting the earth by selecting it (either by clicking on it or pressing Return or Enter on the keyboard and typing its name), and then pressing Y on the keyboard.

You also might want to toggle cloud-rendering by pressing I.

Lastly, you can get rid of a pesky blue sky by turning off atmosphere rendering, by going to the Render menu, selecting View Options and unchecking Atmosphere.

To go to a particular latitude or longitude on Earth:

How to figure out what tropical, not sidereal, zodiac sign anything is in while viewing the sky from the Earth's surface

Those of you out there who are interested in astrology can easily figure out what zodiac sign various things are in by going to a location on the earth's surface (as described above), then pressing ; on the keyboard to show an "earth-based equatorial coordinate sphere".

Look around the sky until you find the center of the wheel. Looks kind of familiar, doesn't it. (Actually, though, in case it's too hard to find, here's a Celestia link directly to an example of what I mean - at the date and location of my birth).

The 12 pie slices you see are pretty much equivalent to the 12 tropical zodiac signs. But how do you tell which one is which? Well - this probably won't work for dates in the distant past or future, due to the precession of the equinoxes.

But, in dates close to the present, if you turn on constellation labels by pressing = on the keyboard, Ursa Minor will be found in the pie-slice which (I think?) contains things in Scorpio. The next pie slice counter-clockwise after that (I think?) contains things in Libra, and so on.

Of course, at any particular time, generally the only things you'll see in the sky are the things that are in the astrological houses 7 through (and including) 12, since those are the only houses visible above the horizon. (Though you might able to see some things that are at the beginning of astrological house 1 and the end of astrological house 6, very close to the horizon).

UT = Universal Time = GMT = Greenwich Mean Time

If it's 12:00 PM Eastern Standard Time, GMT or UT is 5 hours ahead, so it's 17:00 GMT or UT.

If it's 12:00 PM Eastern Daylight Time, GMT or UT is 4 hours ahead, so it's 16:00 GMT or UT.

For other time zone information, look here: http://www.computerhope.com/jargon/t/time.htm

Links to locations within Celestia

Celestia web links

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This page uploaded to web: August 6, 2006
Last modified: Oct. 12, 2007