Control Panel in the DOGULEAN Planetarium

You unless you are a quick study, you should work through the tutorials on Stargazing and Space Travel before you do this one. I will assume that you are familiar with the concepts introduced in those tutorials and if something on the control panel does the same thing as something we covered in those tutorials, I will just say so and maybe show it, but I won't do much explaining.

I suggest that you open the Planetarium in another browser window and follow the tutorial there.

The basic principle about the Control Panel is that you can control everything using the Control Panel. (The position of the point at the center of the screen, top right in the on-screen controls, is not on the control panel, but then, it is not something that we control.)

There are some important things that you can do using the Control Panel but not using only the mouse and on-screen controls. Special abilities of the Control Panel are important in the adventure videos about the Total Solar Eclipse.

1. The Basics of using the Control Panel

  1. We open or close the Control Panel by right-clicking the mouse. We can also close it by pressing the Dismiss button at the bottom of the Control Panel.
  2. You can drag the Control Panel by holding down the left mouse button on its title bar. This may not work with touch screens.
  3. We open or close a section of the Control Panel by clicking the left mouse button on ts heading.
  4. In this tutorial we will go through the Control Panel section by section and look at its capabilities in both modes, Stargazing and Space Travel.
  5. To start, I suggest that you set defaults by pressing the "All Defaults" button at the bottom of the Control Panel. Or at least set Stargazing mode since we will start each section in that mode.
Before continuing with the tutorial, go through the whole control panel, in both Stargazing and Space Travel modes. Try all the settings and see if you can understand what they do.

2. Viewer location – stargazing mode

  1. Open Viewer Location by left-clicking on it.
  2. In Stargazing mode, using this section is the only way to change your location.
  3. You can set latitude or longitude by using the sliders, by clicking or pressing and holding the adjustment arrows in the boxes, or by typing into the boxes.
  4. If you type something wrong into the boxes and get an undefined position, you can rescue yourself by using the sliders.
  5. If you have access to a geolocation service and you gave the Planetarium permission to access your location, you can set your position by pressing Set From Geolocation. If not, then nothing will happen when you press that button. The first time you use geolocation, it may take a little while.
  6. Your browser will probably cache the results of geolocation, so if you move to a new place, you may need to restart your browser for geolocation to set your new position.

3. Viewer location – space travel mode

  1. Switch to Space Travel mode.
  2. Home Planet is which planet we are on, same as the "H:" button at lower right.
  3. When our home planet is Earth, Set From Geolocation is still available, but if we change to any other home planet, the button disappears.
  4. There is a new setting, Position Type. It selects either Fixed or Floating style of position, the same as the button at lower left. The two controls always have the same value.
  5. The other new setting is Altitude. It indicates our distance from the center of the planet, measured in radii of the planet. The minimum altitude is 1, meaning that we are on, or actually just above, the surface of the planet.
  6. We can control altitude either here or by using the mouse wheel, as we did in the space travel tutorial.
  7. "Turning over" our planet by left-dragging on it is another way to change our latitude and longitude, though it is not as accurate as using the Control Panel.
  8. Close Viewer Location.

4. View in Stargazing Mode

  1. Change back to Stargazing mode and open View.
  2. Elevation is looking up or down – the same as left-dragging the mouse vertically.
  3. Rotation is turning around on the spot, like left-dragging horizontally.
  4. Zoom tells us how many times the view is magnified.
  5. Elevation and rotation form alt-azimuth coorinates. That means that rotation (azimuth) 0° is North and the angle of rotation increases as we turn clockwise.
  6. View Planet is a menu that selects a planet to look at, the same as the "V:" button at lower right.
  7. Pressing Restore View Defaults sets Elevation 22° Rotation 90° (due East) and Zoom 1.
  8. Most settings will be preserved when you reload the planetarium page, or leave it and revisit it later, but the zoom will be reduced to at most 5 if you do that. The reasons for this will be given in the section on Date and Time.

5. View in Space Travel Mode

  1. Switch to Space Travel mode.
  2. We can control Roll precisely. Roll 0° is Earth level beneath our feet.
  3. In Space Travel mode, View Planet still does the same thing as the "V:" menu at lower right. In particular, it orients the planet so north pole is at the top.
  4. The Tracking menu does the same thing as the "Tr:" menu as lower right.
  5. Restore View Defaults also sets Roll to 0° and turns Tracking off.

6. Date and Time

  1. Close View and open Date and Time.
  2. The Data and Time settings are the same in Space Travel and Stargazing mode.
  3. We see some things that are the same as the onscreen controls at upper left. Let's look at the things that are new.
  4. There is an extra time field, for seconds. It is only updated when planetary positions are updated. At zoom 1, that is once every 5 clock seconds. We update planet positions proportionally more often as zoom increases, up to at most 10 times a second. That keeps movement of the sky and planets reasonably smooth. But, of course, the seconds field will never be updated more than once per clock second.
  5. You can set the clock's timezone offset from UTC. You would usually do that if you want to view some astronomical event, like an eclipse, and the time you have for it is in GMT (= UTC + 0) or some other timezone. Offsets of all existing timezones are supported. The granularity is a quarter hour. Note that 9.25 means 9 hours and 15 minutes, not 9 hours and 25 minutes.
  6. When you want to go back to local time, press Use Local Time, don't just set the timezone offset. When you press Use Local Time, the Planetarium will know that it is on local time, and it can automatically change to or from Daylight Saving Time, or whatever summer time is called where you are, at the correct moment.
  7. You can set the time rate to make the clock run faster. Pressing "Set Rate To 1" sets the time rate back to normal, which means that one second of real time equals one second of Planetarium time.
  8. If you have some time-consuming setup to do, but don't want planetarium time to change while you are doing it, press Stop Clock. When you restart the clock, it will start running again with whatever rate you have set.
  9. Besides setting the current time, Use Real Time sets the time rate to 1 and starts the clock. It does not set local time. The Real Time button onscreen does the same things as Use Real Time.
  10. One last thing: Suppose you reload the planetarium page or leave it in any way – close your browser, close the tab, or navigate to another page – and revisit the planetarium later. Then:
    • If you are in Real Time when you close the Planetarium, you will be in Real Time when you open it again.
    • Otherwise you will have the same time on the clock, and the same clock state (stopped or started) as when you closed the Planetarium.
    • In either case, the Timezone Offset will not change.
    • If the clock rate is more than 1 when the planetarium page loads, it will be reduced to 1. Otherwise it will stay the same. If you still want a higher clock rate, you will need to set it again.
    • Likewise, when we load the planetarium page, if zoom is more than 5, we set it to 5. Otherwise it stays the same.
    • We treat clock rate and zoom like this for the following reason:
      • At clock rate 1 and zoom 1, if nothing else is happening, the planetarium refreshes the screen once every five seconds. As clock rate or zoom increase, the planetarium increases the refresh rate proportional to rate times zoom, up to 10 times per second.
      • On some devices, refreshing 10 times per second may eat up most of the cycles. The planetarium doesn't have a good way to detect that problem, but if you react in the most reasonable way, by leaving the page, then when you come back, the planetarium will be refreshing at most once per second and the problem should be gone. If it is not gone, you should probably use a different device to run the planetarium.

7. Planet Settings – Stargazing

  1. Get into Stargazing mode and Open Planets.
  2. We have three settings: How much planets are magnified, how much Sun and Moon are magnified, and how bright the Sun is. Why do we need them?
  3. There are two problems with representing the sky on a computer screen.
    1. The sky is big and the screen is not very big.
    2. Stars and planets appear very small in the sky but are often very bright. A computer screen is not very bright – only about as bright as a white sheet of paper.
  4. To understand the first problem, let's view the Sun. It looks a reasonable size onscreen. But according to the second line under Planets, it has been magnified 5 times.
  5. Let's turn its magnification down to 1 – no magnification. Yes, that is really how big the Sun is in the sky – about half a degree across. We could zoom in to bring the Sun back up to a reasonable size, but then we wouldn't see much else. Try that for yourself.
  6. Press Restore Planet Defaults.
  7. We don't have really have any issue about how bright the Sun and Moon look onscreen. They don't look nearly as bright as they really are, but they look bright enough.
  8. For stars and planets, we can't make them bright enough to see at their true size, so we have to make up for it by making them bigger.
  9. The first line under Planets says that planets in general are magnified 40 times. Not the Sun and Moon, which are only magnified 5 times, and not the Earth, which is not magnified at all, because it does not need it. All the other planets.
  10. If we try this with a prominent planet, like Venus, we will see how it works. With no magnification, we can't even see it.
  11. The last setting, Sun Brightness, does not control how bright the Sun looks, but how brightly it shines on the planets. If we view a prominent planet, like Jupiter, and turn Sun brightness down and up, we see how it works. You made want to adjust Sun Brightness depending on what you are looking at.
  12. Press restore planet defaults and let's go on.
  1. View the Sun. (If necessary, change the time or your location so it is in the sky.) Turn Sun/Moon Magnification down to 1 and zoom up to 5. Sun and Moon will be the right size, but how many constellations can you see?
  2. Set zoom to 1. View Jupiter. Turn Planet Magnification down to 1, then to 10, 20, and back to 40. Which do you like best for "normal" viewing?
  3. View Jupiter and zoom in so you can see its bands. Now turn Sun Brightness down to its lowest value, 0.5, then up to its highest value, 10, then back down to the default, 3. Sun Brightness setting do you like best? Turn zoom back down to 1.

8. Planet Settings – Space Travel

  1. Restore Planet Defaults, if you need to, and set Space Travel mode.
  2. The basic ideas are the same as in Stargazing, but there some differences about what magnification applies to what planets, depending on what your home planet is.
  3. Your home planet is never magnified.
  4. Change Home Planet to the Moon. Now the Sun and Earth are magnified 5 times, or whatever the second line says.
  5. If your Home Planet is some other planet, like Mars, only the Sun is magnified according to the second line. Earth and Moon are ordinary planets and are magnified according to the Planet Magnification line, by default 40 times.
  6. Change Home Planet to Sun. Because the Sun is our home planet, it is not magnified, so the Sun/Moon Magnification line disappears altogether. Nevertheless, if we press Restore Planet Defaults, the second-line magnification will be set to 5.

9. Star Settings

  1. Set Stargazing mode. Leave Planets open and open Stars. Close any other sections of the Control Panel.
  2. We treat stars like this:
    • All stars have the same base size.
    • Each star has a brightness derived from its magnitude.
    • We multiply this number by the Brightness Boost to get an ideal brightness for the star.
    • If we cannot make the star that bright on a computer screen (without changing its color), we make up the difference by increasing the size of the star.
  3. Therefore, if we increase Brightness Boost, dim stars will get brighter. Stars that are already at the full brightness will get bigger. The reverse happens when we turn Brightness Boost down.
  4. As an example, view the Sun. Turn Sun/Moon Magnification down to 1, no magnification. The Sun does not look much bigger than a fairly bright star, such as Fomalhaut. If you find that embarrassing, as I sometimes do, turn Brightness Boost down, too, say to about 10. That looks better, but then you can hardly see most stars.
  5. Restore Planet Defaults and Restore Star Defaults and let's look at Color Level.
  6. Stars have a color in the range red-orange-yellow-white-blue. Color Level controls how strong we make those colors.
  7. At 0 stars are all white. At 10 there are some very strong reds, oranges, yellows and blues.
  8. Restore star defaults close Stars and Planets..
  1. Set a date and time when the Sun and Sirius (α in Canis Major) are both in the sky. (June 1 should be a good date. Turn labels on to help you find the Sun and Sirius.) Turn Sun/Moon magnification down to 1. Adjust Brightness Boost so Sirius does not look much too large compared to the Sun. How many other stars can you still see? Restore planet defaults and star defaults.
  2. Turn the Color Level (under Stars) up to 10 and have a look around the sky. See which stars and star colors you like best. Restore star defaults.

10. Screen Decorations

  1. Open Screen Decorations.
  2. The settings here are mostly self-explanatory. For most, you will see what they do if you just try them. There are some suggestions in the exercises.
  3. The Label Colors setting will not change back to the default if you press Restore Decoration Defaults. The Planetarium assumes that that setting is a preference you want to keep.
  4. Direction Markings are the letters along the horizon, which indicate the compass points. In Space Travel mode, they disappear once you are off the surface of your home planet.
  5. You can turn off on-screen controls if you would rather just use the Control Panel or if you want to take a screenshot of the planetarium window and don't want them cluttering it up.
  • Open the Control Panel and the Screen Decorations section.
  • Turn lines on and off using the Control Panel setting.
  • Turn on labels and try both Label Colors settings. Keep whichever you like best. Turn labels off using the Control Panel setting..
  • In Stargazing mode, find the Direction Markings near the horizon and turn them off and back on using the Control Panel setting.
  • Set Space Travel mode, go to another planet, check that Direction Markings are there, and then turn them off and on by increasing and decreasing your altitude.

11. Changing Modes

  1. In Space Travel mode, there are some settings that do not appear on the Control Panel in Stargazing mode, but can be thought of being there invisibly, with default values.
  2. They are:
    • Home Planet (Earth).
    • Under Viewer Location: Position Type (Fixed), Altitude (1.0).
    • Under View: Roll (0.0), Tracking (None).
  3. When you change from Space Travel mode to Stargazing, these settings implicitly get their default values. If you change back again to Space Travel mode, they will have those default values.

12. All Defaults

  1. The All Defaults button at the bottom of the Control Panel, does the following things:
    • Sets Stargazing mode, if not already set.
    • Viewer Location: Sets Latitude and Longitude using Set From Geolocation. If Geolocation is not available or not allowed, Latitude and Longitude will not change.
    • View: Has the same effect of as Restore View Defaults.
    • Date and Time: Has the combined effect of Use Real Time and Use Local Time.
    • Combined effect of Restore Planet Defaults, Restore Star Defaults, and Restore Decoration Defaults.
Check this for yourself by changing various settings and pressing All Defaults.


Here is a list of things you must use the Control Panel to do.

  1. Change modes.
  2. Location:
    1. Set location precisely.
    2. Set location by geolocation.
  3. View:
    1. Set view components precisely.
  4. Date and Time
    1. Set timezone offset.
    2. Set time rate.
    3. Stop and start clock.
  5. Planets
    1. Set Planet Magnification.
    2. Sun/Moon/Earth Magnification.
    3. Set Sun Brightness.
  6. Stars
    1. Set Brightness Boost.
    2. Set Color Level.
  7. Screen Decorations
    1. Set Label Colors.
    2. Turn Direction Markings on or off.
    3. Turn On-Screen Controls on or off.