# Physics

Sp11 Name: ________________________________

Lab Report for Lab #1: Motions in the Night Sky and the Celestial Sphere

Part I: Observations of the Night Sky

1. Before you make any observations, write down a prediction: Considering that the Sun and Moon both rise and set, predict what the motions of the stars you observe will be.

2. Make and record an observation of the night sky. [Drawings are observations and used by the student to answer questions. Nothing to “report” for this question.]

3. Make and record a second observation of the night sky. [Drawings are observations and used by the student to answer questions. Nothing to “report” for this question.]

4. Compare the two observations you made.

a. Knowing the time between the observations, compare the two and determine whether you observed motion.

b. Then determine the direction and rate of the motion you observed. (About how far did the stars move and in what general direction?)

c. To determine whether you’ve analyzed your data sufficiently, determine the time it would take for a star you observed to set (disappear beyond the horizon).

Part II: Using an Astronomical Model

5. Use an astronomical model to check your observations.

a. Now you can check to determine what objects you saw. Identify at least 10 objects (stars or planets or other celestial objects) from your drawing using the model you chose.

b. Determine the time it would take for a star you observed to set (disappear beyond the horizon).

6. Compare your observations to your prediction. Answer the following questions regarding your observations and prediction. Each answer should be at least a few sentences, not just a single word or sentence. Try to give as complete an answer as possible.

a. Did the stars move as you expected? (If you did not expect them to move, rephrase this question to read: Did the stars stay stationary as you expected?) If the answer is no, describe in detail how the motion of the stars differed from your prediction.

b. Compare the motions of the stars that you observed to the motion of the Sun. Use the planetarium software, the celestial sphere, or a planetarium to simulate the motion of the Sun.

c. Describe, in detail, using only your observations and the model you have (celestial sphere, planetarium or planetarium software) the reason for the apparent motions of the stars across the sky. It is not important that this answer is scientifically correct. It is more important that you base your explanation on the model you are using and the observations you made. (1. Are the stars moving around Earth, or is Earth’s motion causing the stars to appear to move? 2. What does the model you are using make it seem like and 3. why?)

d. Describe, in detail, using resources in your textbook, in the library or on the internet, the reason for the apparent motion of the Sun across the sky. For this response, be sure to cite the resources you use. This answer should be a scientifically correct explanation for the apparent motion of the Sun across the sky. Check with your instructor to make sure you have the correct scientific explanation before you proceed to the next question. Would this reason explain the star motions you observed?

Part III: Evaluation and Final Product of Observations

7. Evaluate the model by answering the questions below.

a. Compare the model you have (celestial sphere, planetarium or planetarium software) to the correct scientific explanation. Does the model demonstrate a correct explanation for the motions of the Sun and stars?

b. Evaluate the usefulness of the model for demonstrating the motions of objects in the sky.

1. Does the model replicate the motions accurately?

2. Is the model easy to use?

c. Evaluate the usefulness of the model for explaining the reasons for the apparent motions of objects in the sky. Does the model create any misconceptions about the motions of objects in the sky?

Part IV: Celestial Sphere

Directions: Use the star charts posted on eCampus to answer the following questions.

8. The Earth coordinates for Dallas, Texas are approximately 32° 47’ (latitude) and 96° 48’ (longitude). How far above my northern horizon should I expect to find Polaris?

9. What would I expect the radius (in degrees) of my circumpolar region be for Dallas, Texas?

10. Sketch an outline of your circumpolar region on Chart 1. Then list the 6 constellations that are located within the circumpolar region for Dallas, Texas.

11. How many degrees exist between a pole and the celestial equator?

12. How many degrees above my southern horizon is the celestial equator?

13. How high above the northern horizon is my zenith from Dallas, Texas?

14. What is the declination of my zenith point, as viewed from Dallas, Texas?

15. How many hours on a clock are in one day?

16. How many hours of sky can I see any time I view the nighttime sky?

17. How many hours exist between the meridian and the eastern horizon?

18. What is the RA of February 21st’s meridian?

19. What is today’s date?

20. What constellation is the Sun in today?

21. When is your birthday? (month and day only)

22. What constellation is the Sun in on your birthday based upon the star charts?

23. Between what dates will Orion be on the meridian at 8pm local time?

24. What star is located at 6 hrs 44 mins right ascension and -16.7° declination?

25. What star is located at 5 hrs 14 mins right ascension and +46.0° declination?

26. What star is located at 5 hrs 13 mins right ascension and -8.2° declination?

27. What star is located at 13 hrs 23 mins right ascension and 55.1° declination?

28. What star is located at 16 hrs 28 mins right ascension and -26.4° declination?

29. What are the coordinates for the star Castor in the constellation Gemini?

30. What are the coordinates for the star Dubhe in the constellation Ursa Major?

31. What are the coordinates for the star Deneb in the constellation Cygnus?

32. What are the coordinates for the star Fomalhaut in the constellation Piscis Austrinus?

33. What are the coordinates for the star Mimosa in the constellation Crux?

34. What is the declination for the vernal equinox?

35. What is the declination for the autumnal equinox?