Planetarium Quick Reference

Pressing the button changes it to Long and shows fuller explanations. The added explanations will have a light gray background.

If you are trying to learn the Planetarium from this page, change each of the “short” buttons to Long, but start with the Basic buttons as they are.

The Elements

To use a pointer other than a 3-button mouse, expand this section and read "Pointers".

Pointers

Here is a summary of how to use various kinds of pointer to get various results.

Three-button mouse	Touch	Buttonless Mouse	Standard Touchpad	Result Produced
Press left button	One-finger touch.	Touch left side of mouse.	Press 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 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.
Mouseover a star, planet, or moon	Brief(!) one-finger touch	Mouseover	Mouseover	Display info bar.
Long click on planet or moon (hold 1.5 sec.)	Long one-finger touch (hold 1.5 sec.)	Long click (hold 1.5 sec.)	Long click (hold 1.5 sec.)	Jaunt to planet or moon.

You can also do a lot using just a keyboard, but that is less practical than using a pointer.

From here on, we will assume a 3-button mouse.

Onscreen Controls

By default, onscreen controls appear at upper right whenever the control panel is not visible. (There is an Option that lets you change this.)

Element	Type	Action
Home Planet	Drop menu With a button (▼ ▲) on each side	Drop menu sets new Home Planet. Buttons decrease or increase altitude above Home Planet.
Fixed/Floating	Button	Whether your position remains above a fixed point on home planet or “floats” above it.
Real Time	Button	Set current date-time, with clock running. By default, uses the user’s local time. (Can change in Control Panel.)
Date-Time	Text with arrow buttons (▼ ▲) above and below each component.	Arrows adjust their component value up or down.

Trackball

The grey sphere at upper left is a trackball. You can change the direction you are looking by dragging on it.

Feature
Scarlet line	Home planet’s ecliptic.
Golden lines	Home planet’s prime meridians and equator.
Big white dot	Home planet’s parent.
Big dim white dot	Direction away from home planet’s parent.
Small white dots	Home planet’s siblings.
Big blue dot	Home planet.
Big dim blue dot	Direction away from home planet.
Small blue dots	Home planet’s moons.
Big black dot	Direction of Home Planet’s celestial north pole.
Big dim black dot	Direction of Home Planet’s celestial south pole.

Note that if you are looking down at your home planet’s north pole. you are looking in the general direction of its celestial south pole.

Lines

The main planetarium screen shows scarlet, gold, and grey lines.

For a planet, the scarlet line is your home planet's ecliptic, the plane of its orbit around the Sun. For a moon, it is the ecliptic of the planet that it orbits (its parent).
The gold lines are your home planet&slquo;s equator and its prime and co-prime meridians (lines of Right Ascension (RA, “sky longitude”) 0° and 180°.
The other lines of Declination (D or Dec.) and RA 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).
The lines are your home planet’s lines, they will change when you change home planet.
A planet’s prime meridian (line of RA = 0) is its line of RA that passes through the point where Earth's ecliptic crossed Earth’s equator from south to north at about 12 noon UTC on Jan. 1, 2000.
Points north of the planet’s equator will have D > 0°. Its north pole will have D = 90°.

Star, Planet, and Constellation Labels

Star labels are color-coded by constellation. More labels will appear with more 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 proportionally.
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 by its appearance. Moon labels should disappear when the moon can no longer be seen as separate from its planet.

Info Bars

When you mouseover or touch a star or planet, an info bar will appear. Several stars or planets may each have a line on the info bar, if they are close to where you are pointing.

For stars, the info bar line contains the stars designation (letter or number and constellation, if any), name, if any, magnitude and intensity. Magnitude and intensity both indicate brightness, but intensity is additive – the intensity of a double star is the sum of the intensities of its two component stars.
For a moon or planet, its line gives its name, distance in Astronomical Units (AU) or kilometers, and how much it is magnified, above and beyond zoom.
1 AU = average distance of Earth from Sun, about 150 million km or 93 million miles.

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, see Pointers, above, under Elements.

Accessing the Control Panel and Its Basic Use

Control Panel Access

Show Control Panel

Control Panel Access
Show Control Panel	Double right mouse click or Left mouse click or touch on “Control” button, half way up the left edge of Planetarium screen or Press `Esc` key.
Hide Control Panel	“Hide” button on Control Panel or Double right mouse click or Press `Esc` key.

Double right mouse click or

Left mouse click or touch on “Control” button, half way up the left edge of Planetarium screen or

Press Esc key.

Hide Control Panel

“Hide” button on Control Panel or

Double right mouse click or

Press Esc key.

Control Panel Global Operations
Restore All Defaults Button	Reset all control settings to their original values, except for those under Options.
Expand or shorten a section	Click on +/− button to expand or shrink the section. (Show or hide Advanced settings.)
Scroll up or down	Vertical left mouse drag on Control Panel.

Sections of the Control Panel

Each section has a button that toggles between Basic and Advanced.

Basic means that only the items on the control panel that are always visible in that section are explained. Advanced means that the additional items that appear when you press the “+” beside that section’s heading in the Control Panel are also explained.

Location

Your Location data consists of:

Your Home Planet.
Your Altitude (distance from Home Planet’s surface), as a number of radii of the planet. Planets are not perfectly round, so this is an average radius.
The point on the planet below you, given by its longitude and latitude.

Location	Change on Control Panel	Change with Mouse or Touch	Comments
Home Planet or Moon	“Home” drop menu. Will contain all planets plus moons of current planet.		Select new Home Planet. Sun will stay in the same position (on or off screen). New Home Planet will be in same position (on or off screen) as the old Home Planet was. Use mouse wheel or touch-drag to scroll the menu.
Home Planet or Moon		Click or touch for 1.5 sec. on destination planet or moon (“jaunting”).	Travel along a straight line to the first planet or moon listed in the info bar, unless it is already your home planet. It becomes your new home planet. Ideally you should end up at a point the same distance in km (not radii) above the surface of the new planet as you were above the surface of the old one. But this distance may be modified so you do not end up too close to or too far from the new planet. (Preserving the distance gives you an idea of the difference in size of the two planets.) You will jaunt at a speed that depends on the distance you will travel, so that the time spent travelling will reflect the length of the trip without taking too long. There is an advanced Location setting that gives you some control over your jaunt speed. To help avoid unintentional jaunting, a warning will appear 1 second before the jaunt starts. If you don’t 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, if you start a new jaunt by clicking on another destination planet, or if you reload the Planetarium web page. Reloading will leave you at the position where you were at the time the jaunt was canceled, usually in the middle of nowhere. Don’t be alarmed!
Floating or fixed position	“Floating”/“Fixed” toggle button.		“Fixed” – stay over the same point on the planet as it turns. “Floating” – the planet turns below you. You still go with it as it orbits the Sun. Note that, when “floating”, your longitude will change continuously with time.
Longitude and latitude		Left mouse drag on home planet. Set altitude to at least 0.1, or not much will happen.	Longitude and latitude are shown beside Location heading. They are those of point below you on your home planet.
Altitude	Slider or number box. The number box has up and down arrows when selected.	Turn mouse wheel with cursor on home planet.	Distance from Home Planet’s surface in radii of Home Planet.
Longitude and Latitude	Sliders and number boxes.		More accurate than dragging on planet. Useful for stargazing if you want to view the sky from a specific place.
Location Decimals	Number box		Number of decimal places shown in Altitude, Longitude, and Latitude number boxes.
Jaunt speed	Drop menu.		Modify jaunt speed. “Instant” means that jaunting is completed immediately, like ordinary planet change. Jaunt speed will be slower near beginning and end of the jaunt, when there may be more to see. The mid-jaunt speed will be faster for longer jaunts and shorter for short ones.
Restore Location 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. By default, MS Edge does not set the correct location.

View

The View data consists of:

The View Point (point at the center of the Planetarium window), given by its Right Ascension (RA) and Declination (Dec. or just D) – sky versions of longitude and latitude. (The RA and D of a point are relative to your Home Planet. See the Information section.)
Orientation (roll), an angle defining what direction is “up” on the Planetarium screen.
Zoom, like the power of a telescope you are looking through. Everything in the Planetarium window is magnified this many times.
What, if anything, you are Tracking. If you are tracking something, then as time goes by it stays at the same place on (or off) screen, with its north pole pointing in the same direction.

View	Change on Control Panel	Change with Mouse or Touch	Comments
View Point (Point at center of Planetarium window)		Left drag anywhere off of home planet. Left drag on trackball will change view point faster. While dragging, a white cross will appear in the middle of the screen.	Equatorial coordinates of view point are shown on “View” line. RA = Right Ascension = sky version of longitude. D = Dec = Declination = sky version of latitude.
Look At (a moon or planet)	“Look At” drop menu.		Bring selected planet to center of Planetarium window. Its north pole will point up. The planet you are looking at may be behind your home planet! Use the mouse wheel or touch-drag to scroll the menu.
Track (the stars or a planet)	“Track” drop menu.		Tracking Stars keeps the view point the same as time passes. Tracking a moon, planet, or the Sun keeps it at the same position on or off screen. If you change planets the tracked planet, will stay in the same place on or off screen. Use the mouse wheel or touch-drag to scroll the menu. Set “Track” to “None” when you don't want track any more!! If you forget, it may look like the Planetarium is acting strangely.
Zoom	Slider and number box.	Turn mouse wheel when the mouse is not over your home planet.	Increasing zoom uses more of your computer’s power. That’s because when zoom increases, the Planetarium increases the screen refresh rate in order to keep motions looking smooth.
Roll	Slider and number box.	Left-drag in the bottom 10% of the Planetarium window.	An angle defining the direction of “up”.
RA, Dec	Sliders and number boxes.		RA (Right Ascension) and Dec, or just D, (Declination) are the equatorial coordinates of the view point. They are planet specific – the same point will have different coordinates on different planets.
View Decimals	Number box.		Number of decimal places shown in Zoom, Roll, RA and Dec number boxes.
Refresh Interval	Number box.		Interval between screen refreshes, in milliseconds. This is a base value. Actual refresh interval is this value / (zoom * time rate), down to a minimum of 40 ms.
Restore View Defaults	Button.		Sets: Zoom = 1, Roll = 0, Tracking = None, View Decimals = 1, Can Roll = true. RA and Dec will represent the direction to the center of your Home Planet.
Can Roll/No Roll	Button.		Appears only when you are on or near the surface of a planet. If you set `No Roll`, the direction “up” from screen center-bottom will always point toward the zenith, the point directly overhead, With `No Roll`, you will be able to move the zenith no lower than the center of the screen. To see more of the sky that is beyond the zenith, drag horizontally to rotate the view, then move the zenith up. 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 arrows to the right and left of the months drop menu will move you forward or back through the months. A day is ALWAYS 24 hours! If changing by a day crosses between summer and winter time, both the hour and the offset from UTC, which appears after the word “Local”, will change.
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. We show the offset from UTC when the timezone is Local.
Time Rate	Number of seconds of Planetarium time that pass for each second of real time.
UTC Offset (UTC +)	In case you want a timezone other than UTC or Local. “Use Real Time” does not change this. If this value is non-zero, “Toggle UTC” will set UTC time.
Clock Running/Stopped	Toggle. “Use Real Time” will start the clock if it is stopped. Stopping the clock is useful if you have some setup that must be done at or near a particular time.

Planet Max Magnification

If you put the mouse on a planet or moon, the last item in its info bar, such as “(4.3x)”, shows how much it is being magnified at that time, above and beyond zoom.

This section mainly covers how much planets will be magnified, above and beyond zoom, in different situations.

There are two reasons why we need to magnify planets in order to see them well.

A planet on a computer screen is nowhere near as bright as a planet in the sky.
At zoom 1, we are cramming a very big piece of sky into the Planetarium screen. Zoom 20 would give something more like real size, but then we would not see enough of the sky to make out the constellations.

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.

A negative side effect of changing magnification this way is to reduce the difference in size between nearby and distant objects. If you don’t want that, there is a setting under Options that causes magnification to be adjusted only for zoom, not distance.

Planet Max Magnification	Comments
Planets	Maximum magnification for all proper planets. Not for the Sun or any moons.
Sun/Moon (and sometimes Earth)	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	Maximum magnification for 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, Other Moons to 5, Sun/Moon/Earth magnification to 5, Sun Brightness to 2.

Stars

Viewed from the surface of the Earth, with default color level, star colors should be about as they appear from Earth. Because the Earth’s atmosphere absorbs about half of their blue light, stars will appear bluer when viewed from space.

Stars	Comment
Brightness	Increasing this value makes dim stars brighter and bright stars bigger.
Color Level	Intensity of star colors. At Color Level 0, all stars are white. At Level 10, they have rather garish colors.
Restore Star Defaults	Sets Brightness to 60 and Color Level to 5.

Information

How to get information about what you are seeing.

Points north of the planet’s equator will have D > 0°. Its north pole will have D = 90°. (D = declination = “sky latitude”).
The gold line with RA = 0° is the one that contains the point where Earth’s ecliptic crossed Earth’s equator from south to north at about 12 noon UTC on Jan. 1, 2000. (RA = right ascension = “sky longitude”).

Information	Control Panel	Mouse or Touch	Comments
Lines	Lines button.		Whether the home planet’s lines of longitude and latitude and its ecliptic are shown.
Star, Planet, and Constellation Labels	“No Labels/All Labels/Planet Labels” button.	Double-click.	Cycle through label states.
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 when a jaunt has really started and when it ends. `ALL` ‐ also annotations that tell about mouse events and touches. These help some one watching a a demonstration understand what is happening.
Trackball On/Off	Button.		Toggles whether the Trackball appears at upper left.
Info Bars	Button.		Whether info bars appear when you mouseover both stars and planets, planets only, or neither.
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 you can click on it.
Restore Information Defaults	Button.		Set: `Lines`, `No Labels`, Annotations `Warn`, Trackball `ON`, Info Bars `All`, Crosshairs `ON`, Controls Tab `ON`.

Options

Options are permanent configuration settings that are not reset by pressing the “All Defaults” button. They are all “advanced” since I think you will seldom want to change them.

Options	Comment
Onscreen Controls (Yes/No/Maybe)	`Yes`: the onscreen controls are always visible; `No`: never visible; `Maybe`: visible when the Control Panel is hidden.
Label Colors (Equi-spaced/Alternate)	Different color schemes for star and constellation labels.
Jaunt alt. factor	Altitude (in home planet radii) will not change by more than this factor when you jaunt. If this factor is 0, you will stay at the same point in space when you jaunt – only your home planet will change.
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. The Home Planet will never be magnified (magnification 1). Otherwise: The Sun will be magnified by the amount on the `Sun` or `Sun/Moon` or `Sun/Earth` line. If the Home Planet is Earth (Moon), then the Moon (Earth) will be magnified by the amount in the Sun/Moon or Sun/Earth line. (From the Earth’s surface, the Moon will look about the same size as the Sun.) All other planets, including Earth, if neither it nor the Moon is Home Planet, will be magnified by the amount on the Planets line. 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 decrease as zoom increases, until the magnification is reduced to 1. With this option, when you jaunt to a planet, it is likely to become much smaller as soon as the jaunt starts.
Coord. Style	`Home Planet` (default): Lines and coordinates (RA, Decl) are those relative to the home planet, as described under View (long mode). `ICRF`: Lines and coordinates are those relative to Earth at 1200 TDT, Jan. 1, 2000.
Alt. Base	Whether altitude 0 is the `Surface` (default) or the `Center` of the Home Planet.
Restore Option Defaults	Set Label Colors to `Equi-spaced`, Onscreen Controls to `Maybe`, Jaunt Alt. Factor to `100.0`, Mag. Style to `Gradual`, Coord. Style to `Home Planet`, Alt. Base to `Surface`.

Using the Keyboard

Most things can be controlled using the keyboard, as follows.

Open or Close Control Panel	Press `Escape` key.
Buttons Number Boxes Select Menus	Press `Tab` until element is highlighted, then press `Enter` (for buttons) or `Up` and `Down` arrows (for 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 use arrow keys.
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. (These were mostly assigned by Johann Bayer in 1603 and by later astronomers for southern constellations. Not by the ancient Greeks!)

Stars in a given constellation will have letters roughly in 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

ΔΟΓΟΥΛΗΣ

The DOGULEAN Planetarium 3.5.1

Quick Reference