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12/17
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Course grades have been submitted. Have a great Winter Break!
Prof. Dinerstein, Brian, and Emma
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12/11
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Exam 3 has been graded and scores are posted on Canvas, Overall semester scores as of now are also posted. To check what letter grade you will receive, find the category of your numerical total course score in the table on the Exams page. Note that we do not round up the scores. For students who did the term paper this is your final score, but we cannot file the course grades until after the final exam since grades for all students must be reported at the same time.
For those students who selected the "Exams-Only" format for the course (rather than the term paper option), the Final Exam is on Dec. 16, 9 AM - noon, in our usual classroom. It will cover the entire semester's worth of material, and will be slightly longer than the earlier exams. You will have to answer 4 questions including at least one essay, rather than 3 total questions. There will be some choice among questions. An updated equations and constants packet suitable for the final exam is posted on the Exams page. This may be helpful as a study aid; also, let me know if you see any typos or omissions.
The overall course score has been computed according to the formula in the Syllabus. Each hour exam counts 25%, x 3 = 75%. If you did the Term Paper, your grade on this assignment replaces the lowest exam score (as long as it helps). If you chose the Exams-Only track, your "re-do" opportunity is the Final Exam, and the best 3 of the 4 exams count. The highest five homework scores count, and any extra points from the Sedna exercise are added before normalizing to 200 possible homework points, that scale to 15% of the semester grade. Students who attended most classes get the full 10% participation credit. For absences in excess of five missed class meetings, one point is deducted per missed class.
If you wish to pick up your graded Exam 3, you can do so at the following times from the office of the indicated person: Thurs., 1-2 PM (Emma), Fri. 1-2 PM (Emma), Mon. Dec. 15, 1-2 PM (Prof. Dinerstein)
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12/8
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Exam 3 has been graded and scores are posted on Canvas, Overall semester scores are in the process of being calculated (awaiting some re-graded Term Papers).
You may pick up your graded exam during office hours this week. Monday and Tuesday office hours are the usual, but adjustments will be made once finals begin, to avoid conflicts. Tentatively, the following additional office hours will be held (it is against University regulations to hold group Help Sessions):
Wed, 1-2 PM (Emma), Thurs., 1-2 PM (Brian), Fri. 1-2 PM (Emma) and
Mon. Dec. 15, 1-2 PM (Prof. Dinerstein)
For those students who selected the "Exams-Only" format for the course (rather than the Term Paper option), the Final Exam is on Dec. 16, 9 AM - noon, in our usual classroom. It will cover the entire semester's worth of material, and will be slightly longer than the in-class exams. You will have to answer 4 questions including one essay, rather than 3 total questions. Some choice will be provided, as well as (the same) equations pages as for Exam 3. If you missed an hour exam, this Final takes its place. If you took all three earlier exams and take the final, we will count the best 3 exam scores.
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12/1
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As of Monday, Dec. 1, the Instructor's Notes are complete. In addition to posting all subsections of Chapter XII, revised versions of VIII.E and VIII.F, with all typos finally (I hope!) corrected, have been posted. Also now available: an Equations Addendum for Exam 3 (see Exams page).
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11/25
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During the week of Dec. 1 - 5, the UT Astronomy Department will be visited by Dr. Meg Urry of Yale, also President-Elect of the American Astronomical Society. There will be a number of events during her visit, but we call your attention to two Public Lectures: Wed., Dec. 3, 4 PM - Black Holes, Galaxies,and the Evolution of the Universe; and Thurs., Dec. 4, 4 PM - Why So Few? The Dearth of Women in Science. See the Astronomy home page for further detail, such as locations.
Exam 3 for Ast 352K will be given in class on Thurs., Dec. 4. The usual procedures will apply. This exam will emphasize the material covered since the previous exam, included in the Instructor's Notes, Ch. VIII.C. to Ch. XII.
Graded papers for Homework 7 and the Sedna Orbit bonus homework question will be returned at the beginning of class on Tues., Dec. 2. Those who did the Term Paper may turn in a revised version up until 3 P.M. on Fri., Dec. 5, or at any earlier time, at your convenience. If you do not turn in a revised term paper, the grade on the version of Nov. 18 will stand.
Keep in mind that the optional Final Exam is on Dec. 16, 9 AM - noon. It will cover the entire semester's worth of material.
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11/19
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Fast-Breaking News: There is a typo in question 4, HW 7. The question should read "The absorption lines of one of the stars shift from +15 km/s to -5 km/s" (not -15 km/s as it says). Also, for both questions 3 and 4, assume that the orbits are circular, but may be tilted at an unknown angle of inclination i.
On Tues., Nov. 18 we started discussing binary stars and how they are used to measure stellar masses. New sections (XI.A. and B.) and the corresponding slides are posted. These are relevant to Homework 7. There will be a Help Session on Wed., Nov. 19 at the usual time and place. In addition, because some of the material was not discussed until Nov. 18, we will not apply the normal lateness penalty to papers turned in by the late deadline of 4 PM on Friday, Nov. 21. Homework is not accepted by email. It must be turned in as hard copy or submitted as a clear, legible pdf through the Canvas interface.
The Elliptical Orbits in-class activity was not completed by most of the groups. We are therefore assigning it as an optional assignment for "bonus" homework credit. Normal homework rules apply, except that it must be turned in by 12:30 PM (before the start of class) on Tues., Nov. 25. You will find the question sheet on the In-Class Activities page.
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11/13
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For those doing Term Papers, we remind you that these are due Tuesday, Nov. 18 at the start of class. They must turned in as hard copy, not emailed. The papers will be read carefully by your Ast 352K teaching team and returned by early next week with comments and grades. If you choose to do so, you may turn in a revised version no later than 3:00 PM on Dec. 5.
We are now talking about stellar motions, orbits, and determining masses of stars in binary systems. Instructor's Notes are being updated. Homework 7, distributed today in class, is due Thurs., Nov. 20. This will be the last assigned homework. The lowest (or missed) two homeworks will be dropped when computing a homework total for your course grade.
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11/3
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Exam 2 is being graded and will be returned in class this week. The letter-grade-to-numerical-score correspondence will be the same as for Exam 1 (see Exams page). This week we will finish Section VIII of the Instructor's Notes and talk briefly about how we observe and what we measure about the Interstellar Medium (the stuff between the stars). Then we will move on to discussing how we measure the motions, orbits, and masses of stars. Homework 6 will be due on Thurs., Nov. 13, and Homework 7 on Nov. 20.
For those doing the term paper, the (firm!) due date for the paper is now Tues., Nov. 18. Anyone who would like another opportunity to review their progress and get help and advice, feel free to make an appointment with the instructor or TA who is handling your paper, or to submit an updated outline or partial draft for additional review and feedback.
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10/24
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You should be aware that the second in-class exam will be given on Thurs., Oct. 30. The same format and ground rules (bring scientific calculator, closed-book but open equations, must come by 12:45 PM) apply as for Exam 1. Exam 2 will cover Sections IV.A, and V through VIII.C. of the Instructor's Notes, although several additional sections are already posted. A second page of additional equations is now posted on the Exams page to help you review for the exam. You will receive both the previous and new Constants and Equations pages during the exam.
In class, we discussed the possibility of having two homework assignments in November (adding up to 7 over the semester). The consensus was that we should, so students will be able to drop the two lowest HW scores instead of just the (one) lowest. It may not be necessary to switch from Thursday due dates to Tuesday ones; we will clarify this after Exam 2.
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10/22
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As mentioned in class (also see slides for Oct. 21), there will be a partial solar eclipse visible from Austin tomorrow, Oct. 23. It begins around 5:00 PM, maximum coverage of about 25% occurs an hour later, and the Sun sets at 6:30 PM. Do not look directly at the Sun! You can make your own pinhole camera to view it, or sometimes cracks between the leaves of a tree provide a set of "natural" pinholes. Or you may come to RLM to view the eclipse with the solar telescope in 13.312 or from the roof. For details, see Eclipse Viewing at RLM.
Clarification on HW 5, question 1. The equation for the observed rotational line broadening is correct, but the description in words is backwards. The equator of the star's rotation is in the line of sight, and its rotational axis is in the plane of the sky, for i = 90 not i = 0. When the rotational axis points toward us, that corresponds to i = 0. With regard to the question about location in the sky, think about "location" in terms of the coordinate systems we discussed earlier in the semester.
Notes will soon be posted through the end of Chapter 8. Details of which sections will be covered on Exam 2 on Thurs., Oct. 30 will be announced in class. Homework 5 will be graded and returned before the exam, and there will be a pre-exam Help Session on Wed., Oct. 29.
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10/17
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New sections have been posted on the Instructor's Notes page, covering the material needed to complete problems 1 - 3 on Homework 5. We remind those who are doing the Term Paper to turn in, on paper (hard copy), a detailed title, short outline, and at least 2 or 3 sources on their topic, including at least 1 technical article, on Tues., Oct. 21. Additional feedback and guidance will be provided, to help you develop your paper. Homework 5 is due Thurs., Oct. 23, and will be the last homework assigned before Exam 2, which will be on Oct. 30.
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10/9
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We are now moving into the part of the semester when we'll be discussing spectra of stars and other astronomical objects in some detail. New sections are being added periodically to the Instructor's Notes.
On Thurs., Oct. 9, we distributed Homework 4, due Thurs., Oct. 16. Office hours and a help session will be held next week. Also, if you have not yet turned in your "choice sheet," opting for the exams-only or term paper track, please do so soon.
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10/7
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On Tues., Oct. 7, we handed out the Coursework Choice Sheet, an important document that needs to be filled out and turned in by Thurs., Oct. 9. This is the page on which you will choose between having your course grade be determined only by exams, homework, and participation; or doing a term paper that can replace a (lower) exam grade. In the first case, if you miss an exam or want to try to improve on it, you must take the final exam on Dec. 16. (However, if you take all 3 in-class exams and are satisfied with your grades, you do not need to take the final.) In the second case, you will also have a chance to do a minor rewrite of the paper after it is graded.
We require that you make a choice, sign the page (a real signature, please!), and turn it in by Oct. 9. If you choose the term paper option, also list or describe 3 tentative ideas you have for a topic.
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10/6
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Lunar Eclipse: There will be a lunar eclipse early in the morning - shortly before sunrise - on Wed., Oct. 8. The umbral (partial shadowing) phase of the eclipse starts at 4:16 a.m. Austin time. Totality (full eclipse) starts at 5:25 a.m. and ends at 6:24 a.m. The eclipse will still be in progress at moonset. Because of the early hour and the fact that the Moon will be very low in the sky during the eclipse, there will not be public viewing on UT telescopes. However, lunar eclipses are best viewed with the unaided eye. The Moon will not "disappear," it will simply get dimmer and redder, like a ghost of itself. If you've never seen a total lunar eclipse, I highly recommend it!
Exam 1 is being graded, but will not be returned until Thursday's (Oct. 9) class. Due on Thursday is the choice sheet on whether you intend to write a term paper for this course, or opt for the exams-only track. In the latter case, you will have to take the comprehensive exam during Finals Exam if you wish to replace an earlier exam score (due to having missed an exam, or having gotten a grade lower than you like).
This week (Oct. 7, 9) we will be talking about methods and instruments for astronomy, and starting the general area of spectroscopy, the key to much of what we know about stars today. We will also resume assigning weekly homework, with Homework 4 assigned on Oct. 9 and due at the beginning of class on Oct. 11.
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9/28
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Our first exam will be on Thurs., Oct. 2, and will cover chapters 1 - 4 in the Instructor's Notes. We will hold regular office hours next week and have a Help Session on Wed., Oct. 1. Recommended study strategies include reviewing the In-Class Exercises and Homeworks; these are posted on the class website. In addition, on the Exams page you will find a draft of the Equations and Constants crib sheet you'll be given to use during the exam. Going over this sheet and making sure that you understand how and when to use these equations, what the symbols mean, etc. is another good way to prepare for the exam.
Reminder: There will be NO individual make-up exams for Exam 1. If you miss this exam, even for a valid reason, your make-up opportunity will be Dec. 16, the comprehensive exam that will serve as the universal make-up exam for the course.
Also: Bring a scientific calculator to the exam. You will not be allowed to use a computer, tablet, or smartphone. You must arrive by 12:45 PM to take the exam, and no one will be allowed to leave until at least 12:50 PM (no taking exams by "relay").
You should be starting to think about whether or not to opt for the "term paper" track. The first handout on the term paper was distributed (and is posted). Towards the end of class on Tues., Sep. 30, we will have a short presentation of advice on how to find the kinds of reference sources needed for the term paper.
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9/19
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We are now up to III.D. of the Instructor's Notes. We will finish chapters III and IV next week (Sep. 23, 25). Homework 3 was distributed in class and is posted; it is due Thurs., Sep. 25. Note that a new supplement, Magnitudes Tutorial, is now available on the Supplements.
Our first in-class exam will be Thurs., Oct. 2. It will be closed-book and closed-notes, but a page of equations and constants will be given to you to use during the exam. Since no one has submitted documentation for accommodations from the SSD office, I conclude that no student requires it. As explained in the Syllabus, if you miss this exam for any reason, even a well-justified one, your make-up exam will be the comprehensive Final Exam on Dec. 16. Alternatively, if you choose the term paper option, your grade on the paper replaces that on the missed exam. There will be no exceptions to this policy.
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9/14
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Update: Just for Monday, Sep. 15, Emma will be covering Prof. Dinerstein's usual Monday office hour from 2 - 3 PM. Emma's office is listed at right.
Update on HW 2: At the end of question 4, part (c), you are asked to check whether asteroids A and B "cross over" in terms of brightness. Translation: if one of these asteroids is brighter than the other at 12 microns, does this situation reverse at 24 or 60 microns? The question asks you to calculate the monochromatic blackbody emission per unit surface area for each asteroid, and compare them (take ratios). To complete the problem, also calculate the ratio of monochromatic luminosities, that is, multiply by the ratio of surface areas, and answer the "cross over" question again for the luminosities.
On Thursday the 11th, we started Topic II on Electromagnetic Radiation, and got as far as page 25 - 26 of the Instructor's Notes. We did not cover the limiting cases of the Planck function yet. However, if you'd like to tackle the last two questions on the homework before Tuesday, please see Section II.B of the notes, which covers this and other aspects of blackbody radiation.
Homework 2 was distributed in class as hard copy, but is also posted on this site. You will need values for various physical constants to do this problem set. A good place to find most of these values is Supplement 2 on the Supplements page.
We did not have time to do the activity on the Planck function in class, but we invite you to work through it by yourself, or with classmates, before Tuesday. I will go over it then, so you can check your work and see the implications of the exercise.
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9/12
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On Thursday the 11th, we started Topic II on Electromagnetic Radiation, and got as far as page 25 - 26 of the Instructor's Notes. We did not cover the limiting cases of the Planck function yet. However, if you'd like to tackle the last two questions on the homework before Tuesday, please see Section II.B of the notes, which covers this and other aspects of blackbody radiation.
Homework 2 was distributed in class as hard copy, but is also posted on this site. You will need values for various physical constants to do this problem set. A good place to find most of these values is Supplement 2 on the Supplements page.
We did not have time to do the activity on the Planck function in class, but we invite you to work through it by yourself, or with classmates, before Tuesday. I will go over it then, so you can check your work and see the implications of the exercise.
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9/5
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We did an In-Class Activity on Thursday, Sep. 4. The questions (but not the answers!) are posted on that menu. Homework 1, due at the beginning of class on Thurs. the 11th, is also posted. See the course syllabus for policies regarding homework format and lateness. The equations needed for question 3, part (c) and question 4 were not explicitly presented in class yet but can be found in Sections I.D. and I.E. of the Instructor's Notes.
A help session for Homework 1 will be held Wed. Sep. 10, 4 - 5 PM in RLM 13.132.
Note on using SIMBAD for the Homework: When you reach the SIMBAD web pages, choose query options "Basic Search" or "[Query] by identifier." SIMBAD knows multiple names for each source. So, for example, you can type "Acrux" or "Alpha Crucis" or "Alpha Cru" or "Alf Cru" (or many other titles) to look up that star. When you click on "SIMBAD search," it will bring up a page of information on the object. You should use the first set of coordinates (ICRS); although it doesn't say so, R.A. is in hours, minutes, seconds of time and Dec. is in degrees, arc minutes, and arc seconds. If your calculator does not deliver trig functions in h m s, you may have to convert the R.A. to decimal degrees.
Next week we will finish Unit I on Positional Astronomy and move on to Unit II, Electromagnetic Radiation. All course-specific content is now password protected. The username and password were announced at the last three class meetings. If you do not know them because you have not been attending, you must come in person to class or official office hours to obtain them. However, if you have missed the first three classes, you may have difficulty catching up and perhaps should consider dropping the class.
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8/29
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We have started posting sections of the Instructor's Notes on this site; you will need the username and password given in class to access these and the Class Slides. You may find it helpful to look over the Notes before Tuesday's class. If you want to do more reading, see the optional readings in books on reserve in the PMA library, and check out Prof. Vincent's website on positional astronomy (on the Helpful Links page).
Please bring a scientific calculator to class on Tuesday for a brief in-class exercise. We will be working in small groups, so you will need at least one calculator per group.
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8/22
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The syllabus for Fall 2014 will be available at the first class meeting on Thursday, August 28. In the meantime, you can access the syllabus from Fall 2013 here, but please note that there will be some changes from last fall's schedule and policies.
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