Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Dialogue Concerning the Two Chief World Systems wikipedia , lookup
Canis Minor wikipedia , lookup
Corona Australis wikipedia , lookup
Cassiopeia (constellation) wikipedia , lookup
Cygnus (constellation) wikipedia , lookup
Perseus (constellation) wikipedia , lookup
Timeline of astronomy wikipedia , lookup
Constellation wikipedia , lookup
Aquarius (constellation) wikipedia , lookup
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?