ASTR 161: the Sky and Solar System


 section class instructor lab instructor
005 T,Th 12:30-1:45, SM 356 Prof. Ready M 9:00-10:50, SM 504 Dr. Requena Torres
006 W 9:00-10:50, SM 504
007 M,W 3:00-4:15, SM 420 Prof. Ready M 12:00-1:50, SM 504 Dr. Walbourn
008 W12:00-1:50, SM 504
101 M 6:00-8:45 Prof. Ready W 6:00-7:50, SM 504 Prof. Ready

office hours

Office: SM 475
Hours: Mondays 4:30pm-5:30pm; Tuesdays 2:00pm-5:30pm; Wednesdays 4:30-5:30pm

I recommend letting me know ahead of time if you’d like to drop by.


ASTR 161 is an introduction to astronomy with a focus on the sky, our Solar System, and how it compares to other planetary systems. With a little curiosity, imagination, and some mathematical tools, you will understand how we come to know what we know about the universe, not just what we know.

Because this class is qualitative in nature, we’ll understand astronomy primarily in plain English, with the occasional equation to help us understand physical relationships 1.

text and polling


Your final grade will use the TU +/- grading system and will be based on the following:

Component % Total Notes
Celebrations of Knowledge (3) 30% because exam doesn’t sound fun; multiple choice; 10% each
Weekly Quizzes, Online 20% lowest score dropped, the rest are averaged
Classroom Participation 20% your total clicker response score as a fraction of the total points possible
Lab 25% lowest score dropped, the rest are averaged; mandatory for credit
Final Celebration 5% cumulative
Total 100%

celebrations of knowledge

We’ll have three exams celebrations of knowledge, each worth 10% of your final score, plus a final CoK that’s worth 5%. One (1) excused exam absence can be made up. Unexcused exams will receive a zero (0) score. Except in unusual circumstances, two missed examinations will result in failure of the course. Cheating on examinations or any other aspect of the course will result in failure of the course and the reporting of the incident to the Vice President for Student Life.

weekly quizzes

Each week, I’ll assign one or more quizzes (usually just one) on Blackboard. The purpose of these quizzes is to get you to review each week, and not the night before the exam. They may be attempted multiple times, and the highest scoring attempt submitted by the deadline is the one that gets recorded.

At the end of the semester your lowest quiz score is dropped, and 15% of the average of the remaining scores are added to your final score.

classroom participation

We will be using Poll Everywhere to record your responses to clicker questions (see registration instructions on BlackBoard). Each class (and some labs) will feature interactive questions. You’ll have some time to chat with your neighbor to determine the correct response. Points are awarded as follows:

  • Correct: 2
  • Incorrect: 1
  • No response: 0

Responses are imported into Blackboard, and your final score is simply your total number of points as a percentage of the total points possible throughout the semester.

grade scale

The standard breakdown of your final grade will be A: 93–100, A-: 90–92, B+: 87–89, B: 83–86, B-: 80–82, C+: 77–79, C: 70–76, D+: 67–69, D: 60–66, F: 59 & below (but seriously, you really gotta want that F).

Students are expected to read the relevant chapters in the textbook ahead of class, and respond to the online quiz on the subject via BlackBoard. This must be completed before 6:00 PM on the day of the next class.


Practical laboratory experiments will be conducted per the schedule above. Although mainly designed to compliment what was covered in class, some labs may be used to introduce new topics. Lab experiments will be posted to Blackboard ahead of each session. Students are expected to bring a printout of the lab experiment with them to each lab session. All lab work is to be completed and turned in at the end of each lab session, so plan to write neatly or print out a couple of copies if you’d like to turn in a human-readable version of your lab 2.

Your final lab grade will be the average of all but your lowest-scoring lab and will account for 25% of your final grade. Note that failing the lab will result in an automatic failure of the class.

tentative schedule

Every class is different so there’s no way I can guarantee we’ll hit every one of these topics on every one of these dates. But to give you some idea of what to look for and when, here’s a possible schedule we might follow:

Week Topics (with relevant section numbers)
1/28 0. Introduction
1.4 Numbers in Astronomy
1.5 Consequences of Light Travel Time
1.6 A Tour of the Universe
2.1 The Sky Above
2/4 2.2. Ancient Astronomy
2.4 The Birth of Modern Astronomy
4.1 Earth and Sky (Equatorial Coordinates)
4.2 The Seasons
4.3 Keeping Time
2/11 4.4 The Calendar
4.5 Phases and Motions of the Moon
3.1 The Laws of Planetary Motion
2/18 3.2 Newton’s Great Synthesis
3.5 Motions of Satellites and Spacecraft
4.6 Ocean Tides and the Moon
2/25 Celebration of Knowledge 1
5.1 The Behavior of Light
5.2 The Electromagnetic Spectrum
5.3 Spectroscopy in Astronomy
3/4 5.4 The Structure of the Atom
5.5 Formation of Spectral Lines
5.6 The Doppler Effect
6.2 Telescopes Today
6.4 Radio Telescopes
6.5 Observations Outside Earth’s Atmosphere
6.6 The Future of Large Telescopes
3/11 15. The Sun: A Garden-Variety Star
16. The Sun: A Nuclear Powerhouse
3/18 Spring Break
3/25 Celebration of Knowledge 2
21. Star and Planetary System Formation
4/1 7. Other Worlds: An Introduction to the Solar System
4/8 8 Earth as a Planet
9 Cratered Worlds
4/15 10. Earthlike Planets: Venus and Mars
4/22 11. The Giant Planets
12. Rings, Moons, and Pluto
4/29 13. Comets and Asteroids: Debris of the Solar System
14. Cosmic Samples and the Origin of the Solar System
5/6 Celebration of Knowledge 3
5/13 30. Life in the Universe (if the schedule permits)
classes end on 5/14
5/20 Final Celebration


Please come to class prepared to learn. As a courtesy to me and your fellow students, do not read extraneous materials, use the computers for non-class purposes, or fiddle with electronic gadgets while you are in class 3. We can take selfies during breaks.

So turn off your phone—or at the very least, set it to vibrate—when you come into the classroom. Thanks.


The Department of Physics, Astronomy and Geosciences (PAGS), in accordance with the Fisher College of Science and Mathematics (FCSM) and with the Towson University Strategic Plan, support initiatives that promote diversity among FCSM faculty, staff and students. We are committed to increasing the quality and diversity of our students, faculty and staff while increasing retention and curriculum initiatives. To obtain further information related to diversity initiatives, please visit:


  1. Relax, it’s nothing you haven’t done before, and you’ll have plenty of opportunities to break the rust off if you haven’t done any math in a while. We’re talking basic algebra and below so don’t stress.
  2. Oddly enough, the easier it is to actually read your lab, the easier it is to grade it. I know, weird, right?
  3. Except when using clickers, in which case fiddle away.