Course Information for Physics 112L Astronomy Lab
by Dr. J.
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Course Information for Physics 112L Astronomy Lab by Dr. J. |
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Astronomy is a study of the contents and structure of the universe and an effort to answer questions about perspective, that is where we fit within that universe. This is the lab designed to accompany the Introduction to Astronomy course, Phys 112. The list of labs is given below. Many of these labs will be held in the PC computer lab in Science 102. We use the CLEA (College Lab Experiments in Astronomy) software developed at Gettysburg College to simulate actual conditions encountered by practicing research astronomers. Marywood owns an excellent 8-in (203 mm) Celestron telescope with a focal length of 2032 mm and of Schmidt-Cassegrain design. It is located on the roof of the Science Building and students will be observing the skies on class nights when the weather is clear. The course grade is determined by 10 labs, your participation in observing sessions, a midterm, and a final examination. See below for a sample midterm and final exam. |
The Andromeda Galaxy |
Click on any of these labs to download a copy.
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Lab 1 |
Introduction |
Basic concepts and observations. |
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Lab 2 |
Determine the lunar phases according to its orbital position relative to Earth and the sun. |
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Lab 3 |
Use sunspot measurements to determine the solar rotational rate. |
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Lab 4 |
Acquire an understanding of the apparent motions of the sun, stars, and planets |
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Lab 5 |
Determine the orbital radius and period of the moons of Jupiter. These values are used to compute the mass of Jupiter using Kepler's Laws. |
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Lab 6 |
Generate the spectra of several stars of unknown spectral type and determine the type and temperature. |
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Lab 7 |
Determne the focal length of two lenses, construct a simple telescope, and determine its magnification, light-gathering power, and resolving power. |
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Lab 8 |
Use video clips of a recent transit of Venus to determine the mean distance of Earth from the sun. |
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Lab 9 |
Use the stars in the Pleides star cluster to create an HR-diagram and use it to compute the distance to the cluster. |
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Lab 10 |
Determine and plot the distances and velocities of several galaxies and approxiamte Hubble's constant. |
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Lab 11 |
Create a large-scale map of the universe using right ascension and velocity (redshift) as the coordinates. |
Sample Problems for the Midterm Exam
1. Using 3-hour increments between midnight and noon, fill in the times below for when the moon rises during each phase.
Phase Rises Phase Rises
New Full
Waxing Crescent Waning Gibbous
First Quarter Last Quarter
2. The only star that appears almost motionless in the sky during the evening is ________________. It is the end star in the handle of which constellation? ___________________________ All stars "appear" to rotate in a circular path around this star at a rate of __________ degrees/hour. What phenomenon is actually responsible for this apparent motion?
3. What is the brightest star in the northern hemisphere sky? ___________________ What are the four corner stars in the constellation Orion?
4. On what two dates does the ecliptic cross the celestial equator on the celestial sphere? (These are the equinoxes.) __________________________________________ What angle does the ecliptic make with the celestial equator? ____________
5. Use the celestial sphere or your star map to identify the stars having these coordinates:
Right Ascension Declination Star Constellation
i) 06h 43m –16° 39' ___________________ _______________________
ii) 14h 13m +19° 27' ___________________ _______________________
6. Suppose you have observed Saturn and one of its moons several times over a period of days, keeping accurate scaled distances of the moon from the planet. Then you plot your distances versus time and obtain the following graph. If each mm = one Saturn diameter, find the radius of the orbit and convert it to AU. (1 AU = 1250 Saturn diameters.) Extending the half-wave of the sine curve below would intersect the horizontal axis at 1 day and 7 days. Use Kepler's Law to find the mass of Saturn (in solar masses).
7. A partial table of absolute magnitudes are given below for main sequence stars. You gather light from a star, examine the spectrum, and determine the spectral type to be A0 and the apparent magnitude to be m = 6.3. What is the distance to the star? (in parsecs)
Spectral Type |
M |
B0 |
–4.1 |
A0 |
0.7 |
F0 |
2.6 |
G0 |
4.4 |
8. Suppose the wavelength of maximum radiation in the spectrum of a star is 750 nm. What is the temperature of the star?
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Sample Problems for the Final Exam
Multiple Choice.
1. The only star that "appears" almost stationary in the sky during the evening is
A. Betelgeuse B. Procyon C. Sirius • D. Polaris E. Castor
2. All stars "appear" to rotate in a circular path around the above star at a rate of
A. 1°/day • B. 15°/hr C. 24°/day D. 23.5°/month E. None of these.
3. The lunar phase between full moon and third quarter is called
A. Waxing gibbous B. Waxing crescent • C. Waning gibbous D. Waning crescent
4. What is the brightest star in the northern hemisphere sky?
• A. Sirius B. Betelgeuse C. Arcturus D. Pollux E. Polaris
5. Star Alpha has apparent magnitude m = 1.8 and star Beta has magnitude m = 4.8. What is the
light intensity ratio of Alpha to Beta?
A. 3.0 B. 6.6 • C. 15.85 D. 1000 E. 27
6. What is the (approximate) rotational period of the sun at the equator?
A. 10 hours B. 25 hours C. 15 days D. 2 months • E. None of these.
7. The apparent path of the sun through the sky is known as the
A. equator • B. ecliptic C. right ascension D. meridian E. None of these.
8. Our Celestron 8 telescope on the roof has a focal length of about 2000 mm. What magnification is obtained using an eyepiece of focal length 25 mm?
A. 25 times B. 50 times • C. 80 times D. 200 times E. None of these.
9. How much more light is gathered by a 20-cm telescope than a 5-cm telescope?
A. 40 B. 4 • C. 16 D. 25 E. None of these.
10. A luminous but cool star would be found in which corner of the HR diagram?
A. Upper left • B.Upper right C. Lower left D. Lower right
11. Using 3-hour increments between midnight and noon, fill in the times below for when the moon rises during each phase.
Phase Rises
New 6:00 am
Waxing Crescent ________
First Quarter ________
Waxing Gibbous ________
12. You measured the H absorption line in the spectrum of Vulcan galaxy to be at 4307.6 Angstroms. If the wavelength of the H line is 4301.2 Angstroms, then compute the radial velocity of Vulcan. (The speed of light = 300,000 km/sec.) [Ans: 446 km/sec]
13. You have determined the Hubble constant to be 70 km/sec/Mpc. Determine an upper bound for the age of the universe. [Ans: 14.3 billion years]
14. The apparent magnitude of a star in the open cluster M21 is m = 4.52. You measure the spectrum and determine the absolute magnitude to be M = –3.07. What is the distance (in parsecs) of this star? [Ans: 329 pc]
15. During a transit of Venus, you compare your measurement of last contact with that of an astronomer in Quito, Ecuador. You determine that the angular separation is 9.5 arcseconds. If the straight-line distance between Scranton and Quito is 4370 km, compute the distance from Earth to Venus. [Ans: 9.5 x 10^7 km]
16. Suppose you have sketched Zantar and one of its moons (Lorus) several times over a period of days, and have kept accurate distances of Lorus from Zantar in units of Zantar diameters (ZD). Then you plot your distances versus time and obtain the graph below.
i) Find the radius R of the orbit and convert it to AU.
(There are 1270 Zantar diameters in one AU.)ii) Find the period p of Lorus and convert it to years.
iii) Use Kepler's Law to find the mass of Zantar. (Be sure to use the correct units.)