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View Full Version : Proper motion of Ursa Major (Big Dipper)



tony873004
2015-Oct-18, 05:38 AM
https://www.youtube.com/watch?v=8p9qhAZx8vU
Here's an animation I made showing the evolving shape of the Big Dipper over 300,000 years. Present-day is in the middle of the vid.

antoniseb
2015-Oct-18, 12:09 PM
Nice. I like that you also included Arcturus.

Hornblower
2015-Oct-18, 01:56 PM
Nice. I like that you also included Arcturus.

If I am not mistaken, Arcturus would have been just outside the left edge of that field of view, rapidly moving top to bottom toward Spica.

DaveC426913
2015-Oct-19, 05:25 PM
That's very cool but it took me several retries to even see which stars to observe.

What would be cool is some subtle indicator of the stars in question. (Not overdone though. Say, a paused few seconds at the start, with a halo or arrow pointong at the stars, which goes away when the animation starts)

antoniseb
2015-Oct-19, 10:34 PM
I was curious as to which two bright stars are the ones that cross paths near the end of your window.

tony873004
2015-Oct-20, 01:32 AM
I was curious as to which two bright stars are the ones that cross paths near the end of your window.
I don't know if they have proper names. They might not even be naked-eye bright in the current epoch. Their Hipparcos numbers are 102422 & 81693. They're not very bright at the beginning of the simulation, so they probably have high radial velocity, and get bright as they get close. Our descendants might give them proper names.


If I am not mistaken, Arcturus would have been just outside the left edge of that field of view, rapidly moving top to bottom toward Spica.
That's exactly what its doing. You're right, Arcturus never made in the YouTube video. It's off the left edge of the screen. You have a very good sense of ancient the night sky!

You can run the simulation here:
http://orbitsimulator.com/gravitySimulatorCloud/stars.html?13,39,60,45,22,60,300,-300000,1000,0,100,0,3,0,2,30,0.4,1,0,0,0

This is not a YouTube. You're actually running the sim that made the YouTube. I re-centered, zoomed it out a bit, and turned on the names to answer your questions. Press the Play button ">" to start the sim. You can turn the stars' names on and off using the "Proper" and "Hipparcos" checkboxes.
Arcturus starts near the top, in the center. Spica starts near the bottom, left of center.