ASTR 181 Stars, Galaxies, and the Early Universe


section class SC2230 (PDF) lab SC 1141 (PDF)
001 M,W 10:30—11:45 Prof. Ready Th 12:00—1:50 Prof. Hernandez
101 Th 4:00—5:50 Prof. Etchemaite-Walborn
002 M,W 1:30—2:45 Fr 9:00—10:50 Dr. Scott
003 Fr 12:00—1:50 Dr. Ghavamian
004 M,W 3:00—4:15 Th 9:00—10:50 Dr. Scott
005 Th 2:00—3:50 Prof. Etchemaite-Walborn

Student Hours

M, W: 12—1:15 pm Science Complex, Room 3150M

Can’t make it during those times? No problem! Get in touch with me to arrange a time to meet. Worst case, we can do a Zoom call.

About ASTR 181

The Undergraduate Course Catalog describes ASTR 181 as follows:

A course for non-science majors covering stellar evolution, galaxies, cosmology, and possibly other topics including life elsewhere in the universe. Emphasizes determination of the distance scale and modern trends in astronomy. Development of enough algebra-based physics to understand these topics at a non-technical level. Three lecture hours and one two-hour laboratory period. Students who have successfully completed ASTR 162 will not receive additional credit for ASTR 181. Prerequisite: high school algebra suggested. Core: Biological & Physical Sciences.

Ok, not a bad description, but it could use a little fleshing out. ASTR 181 is an introduction to astronomy with a focus on the life and evolution of stars, how they organize themselves into galaxies, and how the galaxies shape the large-scale structure of the universe. We even get into the evolution of the Universe as a whole, and how it all got started in the Big Bang. 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 learn astronomy primarily in plain English, with the occasional equation to help us understand physical relationships 1.

Lab Fees

The $10.00 lab fee will be used to purchase materials needed for labs and in class activities. Additional information about fees is available at the Provost’s Budget Office.

Text & Polling

Grading & Credit

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 clicker points possible
(which in turn depends on how many poll questions were asked over the course of the semester)
Lab 25% lowest score dropped, the rest are averaged; mandatory for credit
Final Celebration 5% cumulative
Total 100%

Your final letter grade for the class will be based on the rounded value of your final Grade Score and assigned according to the following scale:

A 93—100 C+ 77—79
A– 90—92 C 70—76
B+ 87—89 D+ 67—69
B 83—86 D 60—66
B- 80—82 F 00—59 (but seriously, you really gotta want that F)

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 CoK absence can be made up. Unexcused CoK’s will receive a zero (0) score. Except in unusual circumstances, two missed examinations will result in failure of the course.

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.

Late quiz submissions will not be accepted unless arrangements have been made prior to the due date/time of that particular quiz

Throughout the semester your lowest quiz score is dropped, and 20% 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. 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: 3
  • Incorrect: 2
  • 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.

Although class attendance is not mandatory, if you miss a class, you will miss out on the points that were “up for grabs” that class session. Missed participation points will not be exempted unless arrangements have been made prior to the date of that particular class.


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. All lab work is to be completed and turned in at the end of each lab session. Proper grammar is strongly encouraged 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 weeks. But to give you some idea of what to look for and when, here’s a possible schedule we might follow. Note that I reserve the right to alter the schedule and content as needed:

Week Topics (with relevant text chapter numbers) Lab Note
1/28 1. Introduction
3. Motion, Orbits, and Gravity
Math Review:
Imaging the Universe with Skynet, Part 1
February 6 (Tuesday)

  • Change of Schedule period ends.
  • Last day to drop a course with no grade posted to academic record.
  • Last day to add.
2/4 3. Motion, Orbits, and Gravity
5. Radiation and Spectra
Imaging the Universe with Skynet, Part 2
Blackbody Radiation
2/11 5. Radiation and Spectra Spectroscopy
2/18 15. The Sun: A Garden-Variety Star
16. The Sun: A Nuclear Powerhouse
Classifying Stellar Spectra
2/25 17. Analyzing Starlight H-R Diagram
3/3 Celebration of Knowledge 1
18. The Stars: A Celestial Census
Skynet: Parallax
3/10 20. Between the Stars: Gas and Dust in Space
21. The Birth of Stars
Distances to Clusters & dustiness of space
3/17 Spring Break
3/24 22. Stars from Adolescence to Old Age
23. The Death of Stars
Analyzing the Ring Nebula
3/31 22. Stars from Adolescence to Old Age
23. The Death of Stars (Neutron stars)
24. Black Holes and Curved Spacetime
Supernova Remnants
4/7 Celebration of Knowledge 2 Analyzing Pulsars with a Radio Telescope
Skynet: Standard Candles
April 8 (Monday)

  • Last day to withdraw from full semester courses with a grade of “W.”
  • Last day to change to Pass or Audit grading Option.
  • Total Solar Eclipse is that day so I’ll probably be out of town that Monday. Also, don’t look at the Sun without proper protection.
4/14 24. Black Holes and Curved Spacetime
25. The Milky Way Galaxy
26. Galaxies
The Great Debate
4/21 27. Active Galaxies, Quasars, and Supermassive Black Holes
28. The Evolution and Distribution of Galaxies
Hubble Law and the Age of the Universe
4/28 28. The Evolution and Distribution of Galaxies Large Scale Structure of the Universe Last Lab
5/5 29. The Big Bang
Celebration of Knowledge 3
5/12 No class n/a Last day is Monday and finals begin Wed, May 15

Final Exam Celebration Schedule

Sections Room SC2230 (PDF) Note
001 & 101 Wednesday, May 15, 8:00—10:00 AM Students arriving 30 minutes late (or who don’t arrive at all) without prior communications will not be permitted to take the Final
002 & 003 Friday, May 17, 12:30—2:30 PM
104 & 105 Wednesday, May 15 3:00—5:00 PM

Based on my interpretation of the weird Final Exam Schedule matrix.


be excellent to each other

I can’t believe I have to write this, but bullying, distracting comments, trolling, and acting like a jerk will not be tolerated. The penalty for inappropriate behavior will be determined by me and may include failure and/or removal from the class.

stay on target

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.

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

academic integrity

If you’re thinking about cheating, forget it. Cheating on Celebrations of Knowledge (examinations), labs, or any other aspect of the course will result in a penalty. The penalty for cheating will be determined by me and may include failure of the course and the reporting of the incident to the Vice President for Student Life.

late/missed assignments

Assignments, including (but not limited to) labs, will be accepted late on a case-by-case basis if notice is given prior to the due date of the assignment.

Other Good Stuff


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:

accommodations for students with disabilities

Towson University is committed to providing equal opportunity and access for students with disabilities by removing barriers to participation and providing reasonable accommodations. If you have an Accommodation Memo from Accessibility and Disability Services (ADS), it is important that you share it with me as soon as possible so we can discuss your accommodations as they relate to this course. If you are not registered with ADS and would like more information, please contact the office at 410-704-2638 or or visit the ADS website.


My lectures and course materials, including, but not limited to Keynote presentations, PDFs, tests, outlines, and similar materials, are protected by copyright. I am the exclusive owner of copyright in those materials I create. You may take notes and make copies of course materials for your own use; however, you may not, nor may you allow others to, reproduce or distribute lecture notes and course materials publicly whether or not a fee is charged without my express written consent.

And yes, that includes uploading stuff to sites like Chegg, CourseHero, etc.


  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 arithmetic so don’t stress.
  2. Oddly enough, the easier it is for me to actually read your lab, the easier it is for me to grade it. I know, weird, right?
  3. Except when using clickers, in which case fiddle away.