Unit 1 : Activity 1 : Talking About Things in the Sky : "Which Way is North?" : What's Up? : Unit Exam

Unit 1: How to Point to a Star
Unit 2: Where on Earth Are You?
Unit 3: Earth's Rotation and the Sun's Apparent Motion
Unit 4: Yearly Changes in the Sky
Unit 5: Seasons and Climate
Unit 6: Sundials
Unit 7: Navigation
Unit 8: Ancient Astronomy
Unit 9: Constellations

End of Unit 1 Assignment

This assignment consists of four parts. The first part is a review with a couple of practice questions linked directly to their answers. This is available to all who visit Polaris. The second is a short quiz that you take using Blackboard. This will be available to you when you are enrolled for credit in Astro 102, whether you are in Iowa or somewhere else. It will be instantly scored for you by Blackboard; you only get one chance to take it, however, so be sure you are ready! The third part is an essay question. The question appears below; when you are ready to answer it, log on to Blackboard and submit your essay. Finally, those of you enrolled for credit you should log on to BLackboard and contribute a question, an answer, or a comment to one of the posted topics. (Contribute to the discussion for every unit, not just this one!) If you find the material in this unit challenging, you might want to start with the "discussion" part of the assignment in order to get some help with some of the ideas.

To use Blackboard you will need to be signed up as a student in the course. That means that first you must enroll for credit and then you can login to Blackboard. Beginning spring 2006, enrollment for credit is avialable through http://www.lifelearner.iastate.edu

Brief summary of Unit One:

Topics we have covered include the horizon system of coordinates (altitude and azimuth) and the effects of Earth's rotation on what you can see in the sky.

Before you go to the quiz, see how you do on these two questions. If you have trouble, you might want to review the unit, send a question to the discussion group, or seek help from the instructor.

Practice Question One
A bright star is shining in the southern sky about ten degrees south of your zenith. You email to your astronomer friends "What is that bright object at altitude (fill in) and azimuth (fill in)?" You (do or do not) need to tell your friends what time you made this observation.

Practice Question Two

In this diagram, which observers can see the red star? The blue one?

When you are ready, logon to Blackboard and take Quiz One.

You will get instant feedback on your score on Quiz One (and your instructor will also be informed of your score). If your score is OK, you may proceed directly to the Essay Question One on WebCT. Otherwise, you might want to look at what you missed, ask your instructor about questions you missed, or review relevant parts of the unit.

Essay Question

About forty-five years ago, US astronomers got together and developed Kitt Peak National Observatory near Tucson (about 32 degrees north of Earth's equator). At nearly the same time, US astronomers working in collaboration with astronomers in Chile established a comparable observatory in Chile, about 30 degrees south of the equator. Please explain (in sufficient detail to make it clear to someone with no background in astronomy) why it is that astronomers need to build telescopes in the southern hemisphere when they have some in the northern hemisphere.

Your answer should include a response to the following: The constellation of Ursa Minor is located near the North Celestial Pole, or about 80-90 degrees from the Celestial Equator. Orion straddles the Celestial equator (half N and half S), and the Southern Cross is located close to 90 degrees south of the Celestial Equator. Which constellation(s) can you observe from the observatory in Arizona? ...the one in Chile? ...both observatories?

When you are ready to answer this question, go to Blackboard to write your answer.

Alternative to the Essay Question

If you have friends in South America with access to email, and a good starmap or some familiarity with constellations, you may replace the above Essay Question with this activity:

Arrange to be online at the same time some night. (There will be an hour or two of time difference, most likely, but this should not cause a major problem.) Locate one of these constellations in your sky, and ask your friend to do the same: Orion (best during mid-winter evenings). Scorpius and/or Sagittarius (best during mid-summer evenings). Each of you describe to the other, via email, where in the sky the constellation appears, and how the stars are arranged relative to the horizon. Send copies of your email exchange to your instructor. To describe where the constellation is in the sky, you may use altitude and azimuth, if your friend is OK with those, or you may say "how high" and "North, NE, East, SE, S..." instead.

Don't forget to contribute to the discussion on Blackboard on one of the topics in this unit!

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