MCC PHS 142 M01 Astronomy Homework Ch.6-7
Adjunct: Sam Wormley <swormley1@mchsi.com>
Web: edu-observatory.org/eo/mcc.html
Background Material
Fix - Read Chapters 6-7
Fix - Glossary, pg G-1 words like, opposition, conjunction
Web - http://www.mhhe.com/fix
Web - http://hyperphysics.phy-astr.gsu.edu/hbase/forces/isq.html
Web - http://edu-observatory.org/eo/starcharts.html
Web - http://www.asahi-net.or.jp/~zs3t-tk/atlas_85/atlas_85.htm
Web - http://mathworld.wolfram.com/Eccentricity.html
Web - http://edu-observatory.org/eo/telescopes.html
Web - http://www.celestron.com/education/tel4ast.htm
Web - http://edu-observatory.org/eo/dark.html
Web - http://antwrp.gsfc.nasa.gov/apod/archivepix.html
Web - http://edu-observatory.org/eo/radio_astronomy.html
Homework Problems
Note the answers to the odd (Conceptual Questions, Problems and
Figure-Based Questions) are in the back of your textbook. It is
strongly suggested that you do some of those in every chapter so you
have immediate feedback as how well you are understanding the material.
There are online multiple choice quizzes for each chapter of your
textbook. Goto http://www.mhhe.com/fix then click on
Your book
Student Edition
Choose a chapter
Multiple Choice Quiz
You are expected to do all of your own homework. Statistical patterns
showing copying or collaboration will result in no credit for the
homework assignment for all participants involved. The Code of Academic
Conduct for Iowa Valley Community College District is found in the
Student Handbook.
We all had algebra in high school and the algebra in this astronomy
class is pretty trivial. But if you need to review, look at this
Introduction to Algebra
http://www.mathleague.com/help/algebra/algebra.htm
Problem 1:
Determine in what constellation, Venus appears to be on your next
Birthday. Note the Right Ascension, in degrees for the first day of
each month, is on the back of your planisphere. The declination is that
of the ecliptic as planets tend to follow the ecliptic.
Problem 2:
Listed in the table below are the equatorial coordinates in Right
Ascension (RA) and Declination (Dec) for the Sun, Moon and Planets.
Also listed are distances from the Sun in astronomical units (AU) and
the visual magnitude (V) of each body as it appears from MCC.
Limb Equ: Topo 2000.0 2/12/2008 3:00:00 UTC: (Feb 11, 2008 9pm)
-------------------------------------------------------------------
Cns RA (hr:mm:ss) Dec (d:mm:ss) SnDst(AU) V-Mag
-------------------------------------------------------------------
Sun Cap 21:40:01.52 -13:57:46.1 -27
Moon Psc 1:26:54.33 13:39:34.0 0.9859 -11
Mercury Aqr 20:51:02.75 -14:01:43.5 0.3655 1.9
Venus Sgr 19:39:17.99 -21:17:43.3 0.7257 -4.0
Mars Tau 5:37:00.08 26:30:05.1 1.6261 -0.3
Jupiter Sgr 18:52:35.29 -22:46:46.2 5.2324 -1.9
Saturn Leo 10:33:54.66 10:59:50.2 9.2772 0.6
Uranus Aqr 23:13:39.36 -5:46:36.1 20.096 5.9
Neptune Cap 21:36:28.33 -14:34:01.5 30.041 8.0
Below are two sky charts centered on 6hr RA and 18hr RA respectively.
The celestial equator (0° dec) runs through the center of each.
Plot and label the positions of the Sun, Moon and planets from their
coordinates from the table onto the following sky charts.
Sky Chart - Right Ascension 0h-12h (right-to-left) ±90° Dec
Sky Chart - Right Ascension 12h-24h (right-to-left) ±90° Dec
Problem 3:
What is the wavelength of electromagnetic radiation that has a
frequency of 3 x 1016 Hz? In what part of the spectrum does this
radiation occur? Hint: if you use Figure 6.5 on page 105, look at
Appendix 17 on page A-14. One could also use equation (6.2).
Problem 4:
How close to the Sun would a spacecraft have to go to reach the
distance that the flux of solar energy (intensity of heat and light) is
20 times as large as the solar energy flux at the Earth? Hint:
Think about this--Newton's inverse square law applies. You could
estimate this graphically or you could create and use a formula.
Problem 5:
Suppose atoms at rest emit visible light with a wavelength of 500 nm.
At what wavelength would the light from the atoms be observed if
the atoms were moving toward the Earth at a speed of 20,000 km/s?
Hint: Would equation 6.3 be useful as an step toward the answer?
Problem 6:
A 4-meter optical telescope operates at a wavelength of 5 x 10-7
meters. How large would an infrared telescope operating at
10-4 m have to be to have the same resolution as the optical
telescope? Hint: You could create an equation equating ratios.
Problem 7:
An astronomer observes Mars at opposition using a telescope that has an
aperture of 50 cm (20 inches) in diameter. The astronomer observes in
visible light at a wave length of 500 nanometers (nm). What is the
smallest feature the astronomer could resolve assuming no degradation
by the Earth's atmosphere. Hint: To do this problem you have to
know:
o What does it mean that Mars is at opposition?
o What is the distance between Earth and Mars when Mars is at
opposition?
o What is the angular resolution of the astronomer's telescope?
Yes you can use equation (6.6) to determine the angular
resolution. You must keep track of units and convert them so that
the the numerator and denominator are in the same units.
o Once you have the angular resolution, either use trig, or the
small angle equation (3.1) or (3.2) to determine the the smallest
feature the astronomer could resolve. Show all of your work
including all units.
Problem 8:
Use Figure 6.5 to find the wavelength of a radio wave with a
frequency of 106 Hz. Hint: Appendix 17 on page A-14.
Problem 9:
Using your star wheel (planisphere), determine how many hours and
minutes the star Sirius is above the horizon.
Problem 10:
Use Figure 7.4 to find the pressure at an altitude of 20 km.
Problem 11:
How does the brightness of sunlight at Neptune's distance compare
with the brightness at the Earth? Hint: Newton's inverse square law
applies.
Problem 12:
The half-life of an unstable isotope is 10 years. After what length
of time would there be less than 1% of the original atoms of the
isotope remaining? Hint: There isn't any applicable formula in your
textbook, so you should approach this graphically.