Astronomy 10: Observing the Moon

Observing the Moon

Worth 30 points -- Due Monday, July 1st 2002

A critical part of the scientific process is making your own observations. From observations one must then draw appropriate conclusions and report their results. To help you gain an appreciation for this you can observe the Moon as a good example.

Choose a location where you will have an un-obstructed view of the sky (roof of a tall building, peak of a hill or mountain, or a large clearing). The roof of Campbell Hall is a good spot for this lab. The building will be locked after 6PM, but on nights that there are star parties you will be able to get in. Wherever you choose, always make your observations from the same location.

Choose a time from which to observe from this location. You should observe the Moon at this time for 2 weeks or until it is no longer visible at that time. Then you may alter your observing time appropriately. You should continue to observe the Moon throughout one complete cycle of phases. Given the brevity of this course you should decide early if you are going to do this lab and begin your observations on or before Sunday, June 2nd. A good time to start looking in this time frame would be sunrise (or a few hours after). Around the date of June 10th you might want to try observing around both sunrise and sunset for a couple of days to see which will be better for the next two weeks. You should observe every-other day/night if you can, and daily would be even better.

You should record the following things for each observation:

  1. Location of Observation
  2. Time and Date of Observation
  3. Weather Conditions at that Time and Location (cloudy, foggy, clear, etc.)
  4. The Moon's position with respect to the compass directions on the horizon (North, East, South, and West).
  5. The Moon's phase with a sketch and a name (i.e. crescent, gibbous, quarter, etc.)
  6. If possible, the Moon's position with respect to bright stars in the sky (the Sun counts as a bright star).
If the weather is foggy and you cannot make an observation at that time record that information. You should make these observations in a single notebook that you will hand in at the end of the project. Be as artistic as you want with the sketches and observations. You make take photographs if you so desire. Probably the best thing to do would be to make a sketch of the horizon from where you are making your observations and label it with the compass directions (North, East, South, and West). Then make photocopies of these sketches and draw the moon in when you make your observations.

On or about June 30th you should wrap up your observations of the Moon. At this point make a prediction as to where the Moon will be and what phase it will be in at the conclusion of class (12:00 PM noon) on Tuesday, July 2nd. Write the prediction down. At the conclusion of class we'll all step outside to see if your predictions were accurate.

Beside the observation notebook you should also turn in a discussion of your results. In your discussion, you should answer the following questions:

  1. Why is the Moon in a different place each night?
  2. Did the Moon's phase change with its position in the sky?
  3. Was the Moon always up at the time of your observations?
  4. Is the Moon sometimes visible throughout the day? Explain using your observations to support your conclusion.
  5. What causes the Moon's phases? Explain the variation in lunar phases with pictures and words.
  6. Based on your observations, what is the approximate orbital period of the Moon around the Earth?
  7. What did you learn about the Moon in this exercise that you did not know before?

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