Fall 2006 Astronomy 110 Tu, Th 9:00 - 10:15


When you tell someone about a movie you saw, they may ask `why did this person do what they did?' If the movie is was good, you can answer this question in terms of what you know about the character's goals and desires - for example, `She dressed like a man because she wanted to be an actor and only men were allowed to be actors.' When you do this, you recognize that motivation comes from within a character.

Real life is like that too. For example, let's say your friend decides to visit the Big Island. If you happen to know that your friend has relatives in Hilo and wanted to visit them, then you understand your friend's motivation. Again, your friend's motivation is an aspect of their personality - not imposed from outside, but something which is part of them.

Now think about your motivation. Why do you want to take this class? Maybe that you are curious about astronomy and want to learn something about it. I sincerely hope so - curiosity and a desire to learn are the best motivations you can possibly have.

Or perhaps you have only a little interest in astronomy, but need the credit because it enables you to go on and study another subject that really interests you. That's OK, too, as long as you remember your original goals and recognize that doing well in this class will help you achieve them.

But if you have no real interest and simply need a science credit to graduate, then you may have a tough time with this class. Astronomy is not easy - both logic and imagination are required to understand something about the entire Universe. You can pass the course, but it may take some hard work.

Whatever the source of your motivation, I will do my best to help you out, answer your questions, and encourage you to succeed. But - and this is important - I can't create your motivation. Your motivations are part of your personality. I can no more motivate you to study astronomy than I can tell you what foods you like, what music you enjoy, or what kind of friends you want. That's definitely not my job, and I'm very happy that it's not!

If you understand that motivation is your responsibility, I welcome you to this class and to the study of astronomy.


There is no getting around the fact that mathematical reasoning is an important part of astronomy. Students sometimes suggest that astronomy would be easier to understand if it was taught without mathematics. But without math, astronomy is little more than a random set of facts and a collection of pretty pictures. Math is the `glue' which holds the subject together.

Likewise, some understanding of physics is essential to the study of astronomy. Planets, stars, and galaxies are all physical objects, and they obey the laws of physics. Astronomers use these laws to understand the observations they have made. Without physics, we would have no way of knowing what kind of universe we inhabit.

This course has no prerequisites; any student at the University of Hawaii may take Astronomy 110. But as a University student you are expected to have some basic knowledge. Elementary arithmetic, fractions, percentages, and scientific notation (`powers of 10') will be used throughout the course. Simple algebraic equations and geometric diagrams are used as required; I'll explain things as I go along, but you must make the effort to understand, and to ask questions if you find something confusing. Keep in mind that the purpose of equations and diagrams is to express relationships between different quantities; an equation is not just a `formula' for calculating answers! Some basic facts about logarithms and trigonometry will also be useful. Finally, physical ideas will come up in almost every lecture. Concepts like energy, force, momentum, velocity, and acceleration are basic to astronomy; simple facts about atoms, light, electricity, and magnetism are crucial in understanding this subject.

Albert Einstein once said `Everything should be made as simple as possible, but no simpler.' This is a good rule, first because it says that simple explanations are better than complicated ones, and second because it recognizes that some complexity is unavoidable. As a teacher I have no wish to confuse you, and every possible motivation to explain this subject as clearly as I can. But I can't make astronomy perfectly simple - I would be cheating you if I tried! Many college-level textbooks on astronomy have been written, but all use some math and physics. We are using one of the simpler books for this course, and I'll make every effort to explain the material in clear and basic terms. Your part of the bargain is to make a real effort to understand, instead of assuming that science is just too tough. It's not.


The main reading assignments are summarized in the Course Outline, and listed in more detail on the web page for each topic. We're using The Cosmos by Jay Pasachoff and Alex Filippenko as the textbook. You should think of the book as a reference and a source of background information - not a substitute for the lectures! While the book follows roughly the same outline as this course, there are some real differences. Because of this, we will skip some parts of the book, and cover some sections out of sequence.

The most serious problem with this book - and most others on the market - is the way it treats the planets. The book begins by describing the Earth and Moon, then does a grand tour of the other planets in order of their distance from the Sun. This doesn't always make sense - for example, the rings of Jupiter are described before the much more spectacular and important rings of Saturn! Worse still, this planet-by-planet approach makes it hard to recognize the things that several planets have in common, so learning the about Solar System amounts to memorizing the properties of fifteen or so individual planets and moons. (It's a bit like learning the geology of Hawaii by studying each island separately, instead of learning that all the islands formed in the same way and so are somewhat alike). In the lectures I will not discuss the Solar System planet-by-planet; instead, I will try to emphasize the things that different planets have in common.

Many of the reading assignments are pretty short, and you may benefit by looking at them more than once. For example, it's probably a good idea to quickly read the assigned sections for each week's class before Tuesday's lecture; don't worry about understanding the details, just try to get a general sense of the ideas. Then, before Thursday's lecture, go back over the reading more carefully. It may help to highlight key ideas, but don't highlight long blocks of text; try to pick out the sentence or phrase which really explains the point. And don't feel you have to memorize numbers and names - I can't remember most of that stuff anyway, and I'm not going to test you on your ability to memorize trivia!


Weekly homework assignments are an important part of this course. It's impossible to really learn astronomy by just going to the lectures and reading the text - you must also actively work with the concepts, and each assignment is designed to help you do that. The assignments will be fairly short, and each one is directly connected to the topic covered that week. Homework is handed out each Tuesday; as a rule, it's exactly due one week later, and will be graded and returned to you on Thursday. This schedule insures that you tackle each assignment while the relevant class material is still fresh. Partial credit is given for late papers, but you must hand your work to me before the start of class on Thursday.

The assignments will include observations, simple experiments, plotting graphs, basic calculations, and written questions. You will need a calculator, preferably one which can take square roots and cube roots, a ruler marked with a metric scale, and other everyday items.

In every case it's important to show your work and briefly explain your reasoning. For example, suppose you are asked to do a calculation. It's not enough to just write down the final number - you must explain how you got that number to receive credit. This is not just `busy work'; rather, it is a key part of the learning process. In explaining how you found an answer you have a chance to review your reasoning, and this can help you find any mistakes you may have made. In addition, I can give you partial credit if you have the right approach but don't get the right answer. That's impossible if you write down an answer without an explanation! The same goes for observations, experiments, or any other kind of assignment - you must briefly explain what you did to get credit.

Finally, a word about working together on assignments. Studying together can help in solving problems, but you must make sure that everybody is actively involved. If you work in a group, everybody must write their own explanation using their own words. This is very important - expressing yourself in your own terms will help you to understand the material. It's pretty obvious when people copy from each other, and I will not give full credit if people turn in identical answers! On the other hand, I will give full credit if you take the trouble to use your own words - because that shows that you understand the answer. Likewise, if you find an answer to a question in the textbook, don't copy it word for word, but take the time to rephrase the answer in your own terms. Doing so makes the answer your work!

Homework counts for one-third of your course grade.


A brief in-class quiz will be given at the end of each Thursday's class. Each quiz focuses on the key topics covered that week and consists of one question requiring a short written answer. The purpose of the quiz is to make sure that you understand the main point of the week's lectures. Notes and textbooks are not allowed, and you will not need a calculator. Each quiz will be graded and returned to you at the start of next week. Of the fourteen scheduled quizzes, only your twelve best scores will count towards your grade for the course.

The quiz will start ten minutes before the end of class. Once the quiz starts, nobody will be allowed to enter or leave the room. If you finish before the time is up, check over your answer or sit quietly until the class ends. These rules are designed to make sure that everybody have a chance to think without being distracted by other people coming and going.

Makeup quizzes will only be given if you have a legitimate reason for missing class. Legitimate reasons include illness, family emergencies, and college athletic activities. If you miss a class because of illness, you must bring a doctor's note to schedule a makeup quiz (let me know ahead of time if your religion prevents you from seeing a doctor). If you miss a class because you are participating in sports, you must bring a note from your coach before being absent. Makeup quizzes will be oral; the question will not be the same as the one asked in class.

Since Thursday, November 23 is a holiday, no quiz will be given that week. In addition, no quiz will be given on the last class.

The quizzes count for one-third of your course grade.


The final exam will take place in Watanabe 112 on Thursday, December 14 from 9:45 to 11:45. Nobody can be admitted to the exam once anyone has left, so please be on time. You will need a Number 2 pencil to fill out machine-readable forms.

This is a closed-book exam covering the entire course. It will include written questions requiring short answers, simple calculations, and multiple choice questions. You are allowed to bring a calculator and one page of notes.

You must take the final to pass the course. Special arrangements can be made for students participating in organized sports; please ask your coach to contact me before the last day of class. Students absent because of serious illness or family emergencies will be given an `incomplete' grade, but only if they contact me before 5 pm on Friday, December 15.

The final counts for one-third of your course grade.


As a university student, you may be going through a time of rapid change. Perhaps you are living away from home for the first time. You have new freedoms - the freedom to decide your own hours, chose new friends, set your own goals. With those freedoms come important responsibilities.

As a university professor, I assume that you are ready to accept both freedom and responsibility. You are free, for example, to decide to skip the lectures; I can't make you come to class if you don't want to, and I have better things to do than take attendance! But freedom implies responsibility. If you don't attend class, you will miss quizzes and homework assignments as well as a chance to learn the material. If you fail astronomy because you don't show up for lectures, you can only blame yourself, and nobody else will take responsibility for your failure.

Your responsibilities do not end when you come to class. I don't expect you to pay attention 100% of the time, but if your attention wanders then you must make an effort to refocus on the subject. Needless to say, things like talking or reading in class show that you are not even trying to pay attention. I can and will summarize the lectures, review the key points, and in general give everyone a good chance to learn the material, but I can't direct the focus of your mind - you are the only person who can do that.

Likewise, it is your responsibility to know and follow the rules for the homework, quizzes, and final exam. These rules are designed to make sure that everyone gets proper credit for their work. Someone who tries to gain credit without doing the work, or tries to prevent other people from getting credit for the work they have done, is cheating. Cheating is not limited to violations of the rules spelled out above - any action which gives someone an unfair advantage cheats everyone else. Treat other students as you'd like them to treat you.

Joshua E. Barnes (
Last modified: August 21, 2006
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