Celestial Sphere Lab Work Sheets

To be submitted to your lab instructor.

 

1.)  Stars on the sphere are represented by small circles of various sizes.  The larger the circle, the brighter the star.

 

What is the name of the brightest star in the constellation of Cygnus? 

 

 

What is the name of the brightest star in the constellation of Lyra?

 

 

 

2.) Other objects such as galaxies and globular clusters are also marked on the sphere.  Which globular cluster is located near the constellation of Hercules?

 

 

 

3.) Complete the table below.

 

Table 2.2: R.A. and Dec. of Stars using the Celestial Sphere

 

Star Name

Constellation Name

R.A.

Dec.

Arcturus

 

 

 

Sirius

 

 

 

Altair

 

 

 

Pollux

 

 

 

Procyon

 

 

 

Rigel

 

 

 

 

Setting the Globe for a Specific Geographic Location and Time:

 

4.) Which constellation is closest to the zenith at noon?

 

 

 

5.) Which named star is closest to the zenith at noon?

 

 

 

6.) What is the Sun's altitude at noon?

 

 

 

7.) What direction would you face in order to see the Sun at noon?

 

 

8.) How many hours after noon does sunset occur?  (Give your answer to the nearest ˝ hour)?

 

 

 

9.) What is the Sun's altitude now (i.e. at sunset)?

 

 

 

10.) What direction would you face to watch sunset today?  

 

 

 

11.) At what longitude is it now noon?

 

 

 

12.) Is the constellation you found in question 4 still above the horizon at your location?  (Indicate totally, partially, or not at all.)

 

 

 

13.) Mirach (in the constellation of Andromeda) and Markab (in the constellation of Pegasus) are two stars that are just rising at sunset.  Ask your instructor for the location of these stars on the celestial sphere and then complete the table below.  (See the Appendix at the end of this write-up for instructions on how to measure altitude and azimuth.)

 

Table 2.3: Two Stars Just Rising in the Sky at Sunset over Washington, D.C.

 

Star Name

Mirach (located in Androm­eda)

Markab (located in Pegasus)

Right Ascension

 

 

Declination

 

 

Altitude

 

 

Azimuth

 

 

 

Now rotate the sky to 3 hours past sunset.

14.) What are the altitude and the azimuth of the Sun?

 

 

 

15.) Is the constellation from question 4 still above the horizon? (Totally, partially, or not at all.)

 

 

16.) Now what are the altitudes and azimuths of the stars in question 13?

 

 

Challenge Questions

17.)    It is noon on the 20th of May.  You are on a sailboat and you use a sextant to measure the alti­tude of the Sun.  The Sun is to the south and you measure its altitude to be 75°.  What is your latitude?  Explain your answer.

 

 

 

 

 

 

 

 

18.)      You are on the same sailboat as in Question 17, but it is now July 5th and it is late at night.  You have just been through a storm and all of your maps have been washed overboard.  However, being brilliant and resourceful and having taken astronomy at GMU, you realize that all is not lost!  You look for the bright star Vega in the constellation of Lyra and find that it is at your zenith.  A chronometer (i.e. an accurate clock) on board indicates that it is noon in Greenwich, England.

A.) In what body of water are you?

B.) What are your latitude and longitude?  Explain.  No credit will be given without an appropriate explanation.

 

 

 

 

 

 

 

 

Conclusion: