Download The Changing Heavens Over Time Key Commands Constellations

The Changing Heavens Over Time
Key Commands
Constellations buttons: c
v
b
Left Click to select an object
Space bar to center an object
Scroll wheel to zoom in and out
F5 to bring up the date and time box
Ecliptic: , (comma)
F6 to bring up the location box - Make sure Essex, Vermont is the current location. If not, hit
F6 and next to the magnifying glass, type in “Essex”. Select “Essex, Vermont” and also check
the “Use as default” box. Now you can close the window.
CTRL Q to quit Stellarium
To Begin With …

Open Stellarium: Start button  All Programs  EHS  Science  Stellarium.

Ensure that Essex is the current location. If it is not, hit F6 and follow the instructions above.

Hit c, v and b to turn on the constellation lines, boundaries and names.
Purpose: To help you understand that the sky changes over time. It is not static or constant.
Changes occur over tens, hundreds, thousands and millions of years.
Changing Bootes
1. Hit F5 and go to 22:00:00 (10:00 pm) on January 1, 2013. If you have not done so already,
hit c, v, and b. Also, hit g. “g” removes the ground to avoid having your view blocked. [Note:
You can stop the clock by moving your cursor to the bottom left of the page and click on the <<
arrows under the date and time.]
2. Find the constellation Bootes. [Hint: Follow the arc to Arcturus.]
3. Click on Arcturus (the brightest star in Bootes) and hit the space bar to center it.
4. Sketch the constellation below on the left. Be neat. Then highlight the year and type in
“55000”. Sketch Bootes below on the right. Be neat. Draw the main stars and connecting lines.
Bootes in the Year 2013
Bootes in the Year 55,000
The Changing North Star and Earth’s Precession
1. Go back to January 1, 2000. Find Polaris in Ursa Minor. Click on it and hit the space bar to
center it.
2. Hit e. This turns on the equatorial grid. The location where all the lines converge sits
directly above the Earth’s North Pole axis. Zoom in a bit. You can see that Polaris is close, but
not exactly above the Earth’s axis.
3. In the upper left corner of the screen, you
will see the name of the star and lines of
information about the star. RA/DE stand for
Right Ascension (analogous to longitude) and
Declination (analogous to latitude). Focus on
the Declination of the “RA/DE (of date)”. A
declination of 90o 0’ 0” would be directly over
the pole.
4. Move forward year by year and find the
year when Polaris is closest to being directly over the pole (i.e. when its DE is closest to 90o).
Year: __________________
DE: __________________
5. Find the year when Polaris is furthest from the pole to the closest thousand years. [Hint:
The DE will be between 40o and 50o.] This will be many thousands of years in the future, so
move ahead in 2000 year increments until you get close.
__________________
6. Find the year when Polaris is back again closest to pole to the closest thousand years.
__________________
7. Based upon your answers in 4 and 6, how long does it take for the Earth to precess (to make
one full wobble).
__________________
8. CHALLENGE: Do any bright stars (brighter than magnitude 2.0) come within 10o (i.e. DE >
80o) of the pole over the next precession cycle? If so, what are their names, what is their
magnitude and what year are they closest to the pole?