End of Unit 3 Assignment
assignment consists of four parts. The first is a review with a couple
of practice questions linked directly to their answers. The second
is a short quiz that you take using Blackboard. 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, for each unit, you should
log on to Blackboard and contribute a question, an answer, or a comment
to one of the posted topics. 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.
Click here for a printable
(.pdf) version of this assignment. To view .pdf files, you will need
the free software Adobe Acrobat - click
here to download Adobe Acrobat.
Brief summary of Unit Three:
In this unit we have covered the apparent daily motion
of the sky that results from the rotation of the earth. We have then
a couple of useful concepts - equatorial coordinates, used to make
a record of the position of an object on the sky independent of the
position of the observer, and meridian diagrams, used to figure out
how high a star or planet will get in a particular observer's 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 star rises five degrees north of due east. Where will
it set? What can you say about the altitude of this star when it transits
Practice Question Two
this meridian diagram what
is the observer's latitude? Is the declination of the red star positive
or negative? What is the altitude
of the red star on the meridian at this latitude if its declination is
15? Is the declination of the blue star positive or negative? Can the
blue star be seen by an observer at latitude 75N? Explain!
When you are ready, Blackboard and
take Quiz Three.
You will get instant feedback on your score on Quiz Three
(and your instructor will also be informed of your score). If your
score is OK,
you may proceed directly to the Essay Question Two on BLackboard. Otherwise,
you might want to look at what you missed, ask your instructor about
questions you missed, or review relevant parts of the unit.
When one of the planets is very bright - like Mars in 2003 - observatories
around the world get a lot of UFO reports along the lines of the
following: "There was a really bright thing in the sky in the Southwest
at supper time; when I went out an hour later, it had moved and two
hours later it wasn't there. That must have been a UFO, right?" Explain
what this observer probably saw and why it appeared to move and then
When you are ready to answer this question, go
write your answer.
Alternative to the Essay Question
Observe a sunrise and determine how far north or south of east it rose -- translate this into an azimuth for sunrise.
On the same day, or as close to it as is possible,
altitude of the sun at noon. (One way is to use a stick of known length
held vertically. Determine the length of its shadow and draw the resulting
triangle on a piece of paper. You can then measure the angle. If you
have trig tables or calculator with trig functions, you can use (stick height / shadow length) = tangent
Don't forget to contribute to the discussion on Blackboard on one of the topics in this unit!