Proper Motion Simulatorby Tony Dunn Follow @tony873004
Over a person's lifetime, the constellations don't appear to change. But over millenia, they noticably change. |
The Proper Motion Simulator allows you to see the stars as they were in the distant past, or will be in the distant future.
It also allows you to take a journey on an imaginary spacecraft through the constellations.
You can even watch in 3d!
This program runs completely within your HTML5 compatible browser. There is nothing to install. You will not be bothered with messages telling you to update your Flash or your Java. It will run on Windows, Mac, iPads, smartphones, Kindle, or anything with a web browser.
|M||Show / Hide controls|
|H||Show / Hide Hipparcos IDs of stars|
|L||Show / Hide proper names of stars|
|P||Pause / Play|
|R||Forward / Backwards Time|
|Q||Generate a link to the current state of the simulation|
Below this button are three more buttons: [>], [<-], [Epoch 2000].
[>] is the Play / Pause button. Your simulation begins paused. Press to begin.
[<-] is the time direction button. Press to make time go backwards and see the constellations in the past. Press again to make time go forwards.
[Epoch 2000] returns you to present day.
Below this is a slider control surrounded by a [-] button and a [+] button. Use these to move immediately into the past or future.
Next comes the simulation speed slider and buttons. Use them to speed up or slow down the simulation.
Your imaginary space ship is initially in the solar system, allowing you to see the constellations as viewed from Earth.
Give your ship some speed, and it will take you on a journey through your favorite constellation.
Star brightness is an arbitrary number between 0 and 200. Use it to adjust the brightness of the stars.
You can also adjust the minimum and maximum size of stars by editing these numbers.
If you want to see Proxima Centauri as it moves through the sky just below Alpha Centauri, you may need to increase the minimum star size.
The Zoom slider and buttons allows you to see more or less sky.
The dropdown list contains all 88 constellations as well as many common asterisms and notable stars.
Choose an item from this list to center it on your screen. Give your ship some speed and journey to that constellation.
You can also manually edit the RA and Dec fields to point to any position in the sky. Just adjust the numbers and press [Go].
You can turn on the Asterism lines to make the constellations look more familiar to you. Check "Names" to see the names of the constellations.
If you want to see the official constellation boundaries, check "Boundaries".
A Right Ascension and Declination grid will appear if you select "Grid". You can change the spacing of the grid lines.
Selecting Stereo allows you to view the sky in 3d. When you choose this, other options become visible.
You can adjust the baseline, which is the distance between your two "eyes". It is set at 1 AU as default. You can manually edit this number to anything you like.
Be careful not to make the baseline too large. Between 1 and 4 LY is usually ideal. Set it to 0.01 to watch nearby stars like Alpha Centauri and Proxima Centauri.
It also allows you to view either "Parallel" or "Cross-eye". This simply switches the two images.
The final controls are "Proper" and and "Hipparcos". Selecting these will identify the stars on the screen with either their proper name or their Hipparcos ID.
Select Orion. Orion is distant and changes very slowly. But the foreground stars move like a swarm of bees.
Select "Stereo" and change the baseline to 3 LY to get a feel for the depth of this constellation.
Give your spaceship some speed and travel to Orion. Watch the Pleiades change shape as you pass them.
Select Pleiades, give your spaceship some speed and fly through them.
Select Alpha Centauri. Increase the minimum star size to 0.5 and slide the brightness slider to maximum, and watch as Alpha Centauri (also known as Rigel Kentaurus) and Proxima Centauri move together against the background stars.
Select "Stereo", and change the baseline to 0.2 LY to witness them as truly "foreground" stars.
Select Barnard's Star. Watch how fast it moves against the background.
To discuss this simulator, visit my forum at Gravitysimulator.com. Suggestions, bugs, interesting uses and all comments are welcome. Forum