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Natural Science - Year I

Unit 5: Planetary Motions

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Lab Assignment for Unit 5

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Natural Science Unit 5 Laboratory Activity:
Planetary Movements

Goal: Observing planets against the background sky

Materials and Equipment:


Attached is a map of the Seattle, WA sky, for 10 October 2019 at 09:00 pm, local Daylight Savings Time. The middle line is your horizon; notice the compass points along it. You are looking southwest in this partial view. The shaded green area below this line shows the stars that are below the horizon. The curved yellow line is the path of the sun (called the ecliptic) against the background of the sky, marked with the months the sun is at that location. Note that the sun is "in" the September range, close to the Autumnal Equinox. The nearly circular white line is the celestial equator. Points along this line are marked at the boundaries of the diagram in hours of right ascension. The sun is near 12 hours of right ascension at the autumnal equinox, half-way around the sky from its 0 hour position at the vernal equinox.

Using the map as a starting point, choose a clear night at a reasonably light-free location, begin observing as soon as it is dark enough, and try to locate the following objects:

  1. the moon, if it is visible
  2. the constellations Sagittarius and Scorpius (these lie along the ecliptic)
  3. the constellation which is setting in the west
  4. the constellation which rising in the southeast
  5. the planet Saturn (setting in the west), just below the Moon
  6. the planet Mars, Venus, Mercury, and Jupiter (already set below the western horizon) [If you are able to observe before 8:00pm you may see Jupiter still above the horizon.]
  7. if you know other constellations, you may want to try and find them as well.
  8. note any differences in locations between your observations and the ones on the map (is Aquila directly over head? what time is it?)
Be careful when trying to find things using the map. This is a 180° map, from east to west looking south, but, like the Mercator projection maps of Earth, things at the top and bottom are s-t-r-e-t-c-h-e-d sideways. Also, only half the sky is visible at any one moment. Where are your "boundaries"?

Data Analysis:

There is no formal data analysis for this observation.


Your written report should include the following sections: