Planetarium Main Page
Technical Background

The DOGULEAN Planetarium 3.4.3

Quick Reference

Click the button above to toggle between "Basic" and "Advanced".

"Basic" describes only the items on the Control Panel that are visible by default. "Advanced" includes the items that appear when you click the "+" buttons beside the section headings on the Control Panel.

The instructions below assume that you have a standard 3-button mouse (two buttons and a mouse wheel) or a touch screen. If that is not what you have, there is a table of equivalents below, under Pointers.

Accessing the Control Panel

The things you are likely to do most can be controlled by clicking or dragging on the screen – for those you will not need to use the control panel..
Control Panel
ShowDouble right mouse click or

Long touch (1 sec.), not touching any planet or moon or

Left mouse click or touch on "Control" tab at middle left or

Press Esc key.

Hide"Hide" button on Control Panel or

Double right mouse click or

Long touch (1 sec.), not touching any planet or moon or

Press Esc key.

Restore All Defaults Reset all control settings to their original values, except for those under "Options".
Expand or shorten a sectionClick on +/− button.
Scroll up or downLeft mouse or one-finger drag up or down on Control Panel.


Your Location consists of:
Location Control Panel Mouse or Touch Comments
Home Planet or Moon "Home" drop menu on control panel.

Will contain all planets plus moons of current planet.

Sun will stay in the same position (on or off screen) and new Home Planet will be in same position (on or off screen) as the old Home Planet was.
Click or touch for 1.5 sec. on another planet or moon ("jaunting"). Jaunting will take you along the line to the planet our moon that you click on, usually to a point the same distance above the surface of new planet as you now are above this surface of the old one.

You will jaunt to the first planet or moon listed in the info bar, unless it is your home planet.

By default, you will jaunting at a speed that depends on your planets or moons of origin and destination – so you can enjoy the trip without it taking too long. There is an advanced setting that gives you some control of your travel speed.

To help you avoid jaunting inadvertently, a warning will appear 1 second before the jaunt starts. If you don't actually want to jaunt, lift your finger, release the mouse button, or move the mouse.

A jaunt in progress will be canceled if you change planets on the control panel, start a new jaunt by clicking on another destination planet, or if you reload the planetarium web page. This will leave you where you were when you canceled the jaunt.

Longitude and latitude Left mouse or one-finger drag on home planet. Set altitude ≥ 1.1 first, or not much will happen. Longitude and latitude are those of point below you on your home planet. They are shown (Long. and Lat.) beside the Location heading.
Altitude Slider or number box. The number box has up and down arrows when selected. Turn mouse wheel when info bar listing home planet appears. Distance from Home Planet's center. Unit is Home Planet's radius.
Floating or fixed position "Floating"/"Fixed" toggle button. "Fixed" means you stay over the same point on the planet.

"Floating" means that you don't go around with the planet as it turns. You still go with it as it orbits the Sun.

When "floating", your longitude will change continuously as time changes.

Longitude and Latitude Sliders and number boxes More accurate for setting location on planet than dragging on the planet.

Useful for stargazing if you want to view the sky from a specific place that is not where you are.

Location Decimals Slider and number box. Control the number of decimal places shown in the number boxes under Location.
Jaunt speed Drop menu. Average speed during a jaunt. Jaunt speed will be slower near beginning and end, when there may be more to see.

"Normal" means:

  • Jaunt speed is usually 0.1c among moons of one mother planet (c = speed of light). We use a higher speed (up to 1.0c) for moons that are distant from their mother planet.
  • 100c between inner planets.
  • 1000c going to or from Uranus or Neptune.
  • Otherwise, 500c going to or from Jupiter or Saturn.

"Half", "Double", and "Triple" mean that multiple of normal speed.

"Instant" means that jaunting is completed immediately, like ordinary planet change.

Restore View Defaults Button Sets: Home = Earth, Position Mode = Fixed, Altitude = 3.0, Long. = 0.0, Lat. = 0.0, Location Decimals = 1, Jaunt Speed = Normal.
Set From GPS Button (appears only when home planet is Earth) Sets current longitude and latitude to that provided by the computer.

User must grant permission for Planetarium to receive position information.


The View consists of: The trackball is the little grey ball at the upper left corner of the planetarium window.
View Change on Control Panel Change with Mouse or Touch Comments
View Point
(Point at center of planetarium window)
Left mouse or one-finger drag anywhere off of home planet and trackball.

Left drag on trackball will change it faster.

While left dragging on the screen, a white cross will appear in the middle of it, in case you want to put something there.

Equatorial coordinates of view point are shown on "View" line.
RA = "Right Ascension" = sky version of longitude
D = Dec = Declination = sky version of latitude
(Screen Magnification)
Slider and number box Turn mouse wheel with mouse anywhere off of home planet Increasing zoom increases screen refresh rate.
That causes the Planetarium to use more computational power.
Roll Slider and number box Left-drag the mouse along the very bottom of the Planetarium window. Roll is an angle defining the direction of "up".
Look At
(a planet)
"Look At" drop menu. Bring selected planet to center of Planetarium window, with its north pole pointing up.

The planet you are looking at may be behind your home planet!

(the stars or a planet)
"Track" drop menu. Tracking Stars keeps the same view point at the center of the screen as time passes.

Tracking a moon or planet or Sun keeps that object at the same point on or off screen.

If you change planets using the Planet drop menu on the Control Panel, the tracked planet, not the Sun, will stay in the same place on or off screen.

RA, Dec Sliders and number boxes RA (Right Ascension) and Dec, or just D, (Declination) are the equatorial coordinates of the point in the sky you are looking at. They are planet specific – the same point will have different coordinates on different planets.
View Decimals Slider and number box Control the number of decimal places shown in the number boxes under View.
Refresh Interval Number box Interval between screen refreshed, in milliseconds. This is a base value. Actual time rate is this value / (zoom * time rate).
Restore View Defaults Button Sets: Zoom = 1, Elevation = -89, Rotation = 0, Roll = 0, Tracking = None, View Decimals = 1, Can Roll = true.

Equatorial coordinates will depend on your Home Planet and Location on that planet.

Can Roll/No Roll Button Appears only when you are on or near the surface of a planet.

If you set No Roll, any movement will set Roll to 0, so that up onscreen will be up, the direction away from the center of your Home Planet.

Useful for stargazing.

Date and Time

Date and Time always gives Earth dates and times.
Date and Time Comments
Time settings Planetarium Date and Time. It should be obvious how to set most of these.
The up and down arrows to the right and left of the months select box will move forward or back through the months.
Use Real Time Set planetarium date and time from computer's date and time.
Does not change the timezone.
Toggle UTC Switch between timezone as set on computer (local) and UTC/GMT.
Time Rate Number of seconds of planetarium time that pass for each second of real time
UTC Offset
(UTC +)
In case you weant a timezone other than UTC or Local.

"Use Current Time" does not change this.

If this value is non-zero, "Toggle UTC" will set UTC time.

Clock Running/Stopped Stopping the clock is useful if you have some setup that needs at or near a particular time.

"Use Current Time" will restart the clock.

Planet Max Magnification

This section mainly covers how much larger planets will appear than they should, in different situations.

There are two reasons why we need to magnify planets so we can see them well.

By default, the magnification settings apply when a planet or moon is far away and there is no zoom. As we approach an object or zoom increases, its magnification is reduced until it reaches 1.0. That reduces the difference in size between nearby and distant objects. If you don't want that, there is a setting under Options that sets magnification to be the value shown. adjusted only for zoom.

If you put the mouse on a planet or moon, the last item in the info bar, such as "(4.3x)", shows how much it is being magnified now, not counting zoom.

Planet Max Magnification Comments
Planets All proper planets. Not the Sun or any moons.
Sun/Moon (and sometimes Earth) This is the maximum magnification for Sun. Earth (Moon) should be magnified this much when it is viewed from the Moon (Earth) without any Zoom. From farther away, Earth magnification will increase to that for planets, if that is bigger.
Other Moons All moons except Earth's moon.
Sun Bright(ness) Affects how bright the planets look, not how bright the Sun looks.
Restore Planet Defaults Set Planet Magnification to 40, Local Moons to 1, Sun/Moon/Earth magnification to 5, Sun Brightness to 3.


There are settings for star brightness and color intensity. You probably won't want to use them very often, so they are "advanced".

On the surface of the Earth, star colors should be as they appear from Earth. In space stars appear bluer. The Earth's atmosphere absorbs about half of their blue light.

Stars Comment
Brightness Increasing this value makes dim stars brighter and bright stars bigger.
Color Level Intensity of star colors.

Try turning it up to 10 to see. At Color Level 1, stars are all white.

Restore Star Defaults Sets Brightness to 60 and Color Level to 5.


How to get information about what you are seeing.

Information Control Panel Mouse or Touch Comments
Lines Lines button Planet's ecliptic (plane of its orbit around the Sun) is purple.

Equator and lines of RAthrough the points where equator and ecliptic cross are gold.

Other lines of Right Ascension (RA, "sky longitude") and Declination (D or Dec., "sky latitude") are grey

Lines of D are spaced by 10°.

Lines of RA are spaced by 15° (the angle that the Earth turns in one hour).

Star, Planet, and Constellation Labels No Labels/All Labels/Planet Labels button. Double-click cycles through label states. Star labels are color-coded by constellation. More labels will appear with increasing zoom.

Planet labels are green. Moon labels are smaller and greenish.

Planet and moon labels decrease in size with distance and increase in size with zoom, but less than the change in distance or zoom.

Planet and moon labels are meant to appear when they are needed. Planet labels should appear when you are too far away to recognize the planet. Moon labels should disappear when the moon can no longer be seen as separate from its planet.

Annotations Button Annotations are messages that appear at lower left. There are three levels.
  • NONE – no annotations.
  • WARN – only annotations needed for the user to understand what is happening. For example, there are annotations to tell you that a jaunt has really started and when it ends.
  • ALL ‐ also annotations that tell about mouse events and touches. These useful let let some one watching a video understand what is happening in the planetarium.
Trackball On/Off Button Toggles the Trackball at upper left of the planetarium window.
Info Bars Button Stars: name or number, constellation, brightness as magnitude – smaller is brighter; negative is possible.

Planets: name, distance from viewer to planet's surface, in AU (Astronomical Units) or km, how much the planet is magnified compared to distances between planets and moons.

1 AU = average distance of Earth from Sun, about 150 million km or 93 million miles.

Crosshairs Button Whether the crosshairs appear in the center of the screen when we drag on it.
Controls Tab Button Whether the "Controls" tab is visible in the middle of the left side of the screen. Even if the Controls tab is not visible, it is still there and we can click on it.


Options are permanent configuration settings that are not reset by pressing the "All Defaults" button.
Options Comment
Onscreen Controls (Yes/No/Maybe) "Yes" means the onscreen controls are always visible;
"No", never visible;
"Maybe" means that they are visible when the Control Panel is hidden.
Label Colors (Equi-spaced/Alternate) Different color schemes for star and contellation labels. Use the one you prefer.
Jaunt alt. factor Altitude will not change by more than this factor when you jaunt. That is so your new planet will not be inconveniently small, nor will you be so low that you have to back off a lot to get a good look at it.

If this factor is 0, you will stay in the same place when you jaunt – you will just change your home planet.

Mag Style If the style is Gradual, planet magnification will be as described above under Planet Max Magnification, increasing to the designated value with distance from the relevant planet.

If the style is Exact, each planet will be magnified as follows when zoom is 1.

  1. The Home Planet will never be magnified (magnification 1). Otherwise:
  2. The Sun will be magnified by the amount on the Sun or Sun/Moon or Sun/Earth.
  3. If the Home Planet is Earth (Moon), then the Moon (Earth) will be magnified by the amount on that row. (That means that, from Earth, the Moon looks to be the same size as the Sun.)
  4. All other planets, including Earth if neither it nor the Moon is Home Planet, will be magnified by the amount on the Planets line.
  5. All moons, except Earth's Moon will be magnified by the amount on the Other Moons line.
The amount by which any of these objects is magnified will be decreased as zoom increases, until the magnification is reduced to 1.

Onscreen Controls

When the control panel is closed, onscreen controls may appear at the upper right of the planetarium screen (depending on the Options setting for this). The onscreen controls show the current home planet, buttons for Real Time (same as Use Real Time) and for Fixed or Floating position mode, and date-time components with arrows to adjust those components. These controls work about the same as the equivalent ones on the Control Panel, except that home planet is not a drop menu, it is just the name of the current home planet.

The idea of the Offscreen Controls is that they should be just enough to support a beatific meditative state when you close the control panel and go jaunting around the Solar System. Let me know if they are not, and say what else you really need.

If you would rather offscreen controls appear always or never, there is a setting for that under Options.


Summary of how to use other pointer devices to get the same results as with a three-button mouse.
Three-button mouse Touch Buttonless Mouse Standard Touchpad Result Produced
Press left button One-finger touch Touch left side of mouse Press down with one finger

To left-drag, move mouse or finger while doing this.

With a touchpad, you can press with
one finger and drag with another.

Press right button Long touch (1 sec.)
not on a planet or moon
Touch right side of mouse Press down with two fingers Open or close Control Panel
Turn mouse wheel Pinch or spread two fingers Move a finger along middle of mouse Glide two fingers toward you or away Change Altitude or Zoom
Double click Double touch Double click Double click Cycle star and planet labels
star or planet
(Brief!) One-finger touch Mouseover Mouseover Display info bar
Long click on planet
(1.5 sec.)
Long one-finger touch (1.5 sec.) Long click Long click Jaunt

Using the Keyboard

Most things can be controlled using the keyboard, as follows.
Open or Close Control Panel Press Escape key.
Number Boxes
Select Menus
Press Tab until button is highlighted, then press Enter (buttons) or
Up and Down Arrows (number input boxes and select menus).
Altitude Press Tab until main Planetarium window is focused, then press Page Up or Page Down.
View Direction Press Tab until main Planetarium window is focused, then press Up Arrow or Down Arrow.
Star, Planet, and Constellation Labels Focus any element that doesn't take text input and press L.
Change Star Label Color Scheme Focus any element that doesn't take text input and press C.

The Greek Alphabet

Learn! Astound your friends!

The brighter stars in a constellation have usually been given Greek letters.
The order of the letters will be roughly the order of their brightness.

Α α Β β Γ γ Δ δ Ε ε Ζ ζ Η η Θ θ Ι ι Κ κ Λ λ
alpha beta gamma delta epsilon zeta eta theta iota kappa lambda
Μ μ Ν ν Ξ ξ Ο ο Π π Ρ ρ Σ σ Τ τ Υ υ Φ φ Χ χ Ψ ψ Ω ω
mu nu xi omicron pi rho sigma tau upsilon phi chi psi omega