AST2210 - observational astronomy: review

ABSTRACT

AST2210 is overall an enjoyable subject. It poses some new challenges (as it should) that is hard to overcome, and most of the responsibility is solely on the student him- or herself. The major challenge is writing a proper report structured the Astrophysical Journal-way (which is a big part of this subject) which there are three of. There are no scheduled group sessions, so the students needs to request this every week if this is to happen. There are different lecturers almost every week, and they come in based on their field of expertise. There is a field trip to La Palma (which I unfortunately could not attend) offering hands-on experience on some ground based telescopes. There is much about different observational methods, considering wavelengths, satellites, instruments and more, and a bit of actual analysis of real world data (COBE, CMB). The focus in the lectures is more on the theoretical side considering observational methods, and the instruments supporting them, than the practical side of actually utilizing data, while the reports are heavily rooted in structure and layout, as well as using data for calculations.

MY RATING: 3/5

Fysikkbygningen. The Physical Library is newly renovated and turned into a study area called Entropia. It sports facilitated areas of different sizes to suit every physics students needs. The AST2210 lectures are held in Kristian Birkelands auditorium as of 2018.

Fysikkbygningen. The Physical Library is newly renovated and turned into a study area called Entropia. It sports facilitated areas of different sizes to suit every physics students needs. The AST2210 lectures are held in Kristian Birkelands auditorium as of 2018.

INTRODUCTION

Hello there! Short introduction: I am a student at the University of Oslo (UiO). Currently in my third year doing a bachelor in astronomy (FAM, now renamed FA). I want to do a review of the course, inspired by Astro-Maria who has done the same for several courses while doing her bachelor and masters degree at UiO.

AST2210 is probably the subject that most students in FA feel is the first real astronomy subject because it introduces us to, among other things, ground based telescopes and calculations with real observational data, as well as lectures with scientists working with current experiments. AST2000 did come one year earlier, and it was a great course, but it was an introductory course covering a broad spectrum of astronomy related business, and AST2210 does feel a bit more specialized.

THE REPORTS

The course is built up of three major reports and a final exam. Per 2018 there is no mid-term exam, which will contribute to giving students their first fall break in a long time. The reports contributes approximately 30% of the final grade, and the exam 70%. The reports have been fairly pleasant. They are not so much aimed at the content of the report as they are aimed at teaching us how to write a scientific report, “Astrophysical Journal”-style, which is much needed. The not-so pleasant part of this is that this was our first encounter in strict report typing, and without any prior training we were getting evaluations which contributed to the final grade. During the entire semester, this felt very pressing and demanded 12-14 hour days a couple of weeks. On top of this we got a lot of mixed messages from the professor and from the support teachers on how to construct the reports among other things, which I will get back to soon. FA students needs some more coursing in report writing in addition to this, preferably before. And before you protest on this and refer to the reports that happens in AST2000: those reports were a lot less formal, and the evaluation didn’t care very much about the layout, in my opinion. I have made available some of my reports from AST2000 and my reports from AST2210, if you want to take a look at the structual differences or anything else.

The two first reports were about diffraction and CCD. Diffraction is a known subject for most physics students at this point, especially for those who studied FYS2130 - Waves and oscillations, so the content of the report was fairly simple to put together. We were handed a LaTeX template which fixes all the layout. Overall it works pretty well, but we had some problems getting referencing to work properly. The CCD and the specifics about it is new ground for most students at this point, but the task was not too hard to learn and write about. The third report on the other hand, was entirely other business. The task is to analyze the four year CMB data from COBE. The Cosmic Background Explorer (COBE) was a satellite dedicated to astronomy and the study of the Cosmic Microwave Background (CMB), which operated from 1989 to 1993. While the report was highly educational, it felt all the time like we were writing about something way above our heads, both literally and figuratively. When writing a report in the Astrophysical journal-style (and probably many other styles) the objective parts like data, method, and results arent too difficult to get on paper. The method did pose with some complications because you have to understand what you’re writing, but since you don’t have to deduct equations and explain everything, the method is mostly about listing up equations and models that were used and what they mean. The conclusion and discussion on the other hand was a serious challenge. A good report needs to use the resulting data and conclude with something, and preferably link the data together with other experiments, reports and other relevant material. This is a challenge considering that this is our first meeting with cosmology and real experiments and we have to write conclusions and discussions about the data.

Worth noting is that the analysis we did on the CMB is pretty much the same analysis that Gorski et al. did in 1994, in cooperation with, among others, George F. Smoot who won the Nobel Prize in physics in 2006 for his work on COBE (with John C. Mather). We are encouraged to write a report similar to what top scientists in the field writes, which is to say it mildly, challenging and a bit frightening. We are of course not expected to be at the same level as these guys, but that is where we’re aiming when put up to a task like this.

Summary: The three reports are mostly evaluated on the layout and structure, and account for 30% of the final grade. The reports rise in difficulty, and the final one (as of 2018, COBE) is challenging. You will spend about 80% of your AST2210-time on the reports if you want top grades on them. Spend time on: method, conclusion, and discussion, writing short and consise, being strict on separating information in the different categories. Don’t spend time on: long deductions of equations and explaining your programming.


LECTURERS AND TEACHERS

Next point are the lecturers and the subject coordinators. During the semester we had a few different lecturers as a part of how the course is structured. The main professor is a very likable and down to earth guy, especially considering his line of work. He is helpful and answers every question in great detail, though that can be a bit too much sometimes. But I like his style. He does overexplain sometimes, but if you ponder over his answer for a while, and return to him after a day or two with a rephrased question, you get a new detailed answer which you’ll understand much more of. At the start of the semester, we learned that there are no scheduled group sessions, and no use of Piazza which is widely used in MATNAT and IFI at UiO. We pushed on, and had an AST2210 Piazza created. The answers are frequent and detailed.

We had different lecturers for different parts of the curriculum. I think that was a good initiative, as the lecturers were experts in the subject they were lecturing, and it is always refreshing to have some swapping of lecturers in case it gets a bit boring or tedious. They were of varying quality performance wise, but they were all fairly good! One big miss is that we had a big lecture about the CCD after we had written and handed in the report on the CCD. This should obviously have been before/during writing of the report. Another time, one of the lecturers showed up 30-45 minutes late to the interferometry lecture. I think that we have to expect that one lecture gets a bit messed up during the semester, but this in combination with other factors has made me feel that this course is a bit uncoordinated. This was mostly resolved by us learning and realizing that we cannot depend on this course in the same way we have depended on earlier courses, which is not good considering that we used half a semester on it.

The subject coordinators, or support teachers, were two PhD students, one in solar physics and the other in cosmology (I may be mistaken because I havent specifically asked them of what their fields are). While they were helpful, especially in report writing, I felt that they were a bit uncoordinated with the professor and we got a lot of mixed messages in the beginning of the semester. For example on how to structure the report, and some mathematics, but we gave them quick feedback on this and I havent experienced this later on. I know that some of my co-students have been a bit held back on asking for help and feedback because it has come back as aggressive. While this is somewhat unfortunate, I think that this is mostly about us as students being able to handle and work with different kinds of people, and we should manage that. We should not be forced to like it if we dont, but we can learn from it. Partially due to this, at least me and some of my co-students prioritize going to the professor when we have questions, because we get better answers.

Summary: We’ve had several different lecturers based on their field of work, and they have all been fairly good. Though some of the lectures have been confusing and come in the wrong ordering. The professor is very skilled, both in relaying the information and in the subjects themselves, and gives very detailed explanations. The support teachers are helpful considering writing reports, and somewhat to the subjects themselves, but they were uncoordinated with the professor in the beginning of the semester.

PROGRAMMING

The second report (CCD) introduced us to a new programming language; Interactive Data Language, or IDL for short. Using IDL was entirely optional and using Python instead was no problem for those who chose it. I chose to use IDL because it sounded like a cool challenge, and since I am quite fond of programming and only ever used Python (and a bit MATLAB but I don’t think that counts), I wanted to try it out. It was not a big problem, and overall a fun challenge. I don’t regret it, but if you don’t wanna spend your time on debugging code in a new language, then it’s not for you. If you want to have a look at the code for lab 2, go ahead. IDL has to be used on an UiO computer, preferably through SSH. This is easy to do, but it is a bit messy if you want to edit your code locally on your computer (eg. with Atom or VS Code). To edit it locally is wery much preferable unless you are comfortable using emacs, vim or nano in the command line. My solution was to edit the file locally on my computer, and push it to the UiO computer using Secure Copy (scp) every time I wanted to run it. Using iTerm, I had one terminal session locally on my computer with scp, and another terminal session in SSH to the UiO computer with IDL open. Two more key presses per run compared to Python, but it worked well. IDL is a widely used language in solar physics, and considering its high level nature, it is very easy to use if you have prior knowledge with programming.

The last project incorporated quite a lot of programming in Python. It was important to implement good vectorization of the code to keep the computational time down. With full vectorization, the likelihood estimation in the COBE project took about 10 minutes with a 40x40 grid, and a full 22 hours pushing it to a 500x500 grid. 500x500 was not necessary, but why the hell not. Using a single loop in the main calculation at 500x500 would probably push the calculation time to several days.

CURRICULUM, MATERIAL, AND EXAM PRACTICE

The curriculum is made available to us in the form of slides from the lectures, Kahoot quizes from the lectures and a compendium from the era of earlier professors. We are promised that the exam will start out with a set of short-answer questions (like the exams from the previous two years) that are taken directly form the Kahoot quizes. This makes the goal of practicing for this part of the exam pretty straight-forward.

For me, the compendium is more or less unused. Some parts of the curriculum is not presented in a good way, which have resulted in me not using it. Since I havent used it much, I wont make any conclusions from my experiences.

Since the compendium does not cover all parts of the curriculum, and since we need some things explained twice and in a different manner, we have often been redirected to Wikipedia, forums, and other various sources online. While this can be fitting, it can also be a cheap and bad way to teach. A few times when we physically showed up to ask a few questions, we were asked if we had tried to Google it first. There are a couple of problems with this. Most of us were more or less born with a keyboard under our hands, and Googling is the first thing we ever do before asking anybody. Secondly, when we do show up physically, not using Piazza (or mail god forbid), we are there to speak with a person because there is something we don’t understand. Teaching is about helping others get a better understanding, in a friendly manner. Sometimes direct human interaction is necessary. Another problem about reading about this online, is that, considering that we are beginners at whatever subject we’re stuck at, articles online are very often much too general for our skill level. When working with tasks at the university, we get questions that often are very specific and require specific explanations. Many times, after learning the correct answer, finding the solution on Google seems like the easiest process in the world. But bear in mind that this is after aquiring the correct answer. It is much easier to look for something when you already know where it is (that goes on my tombstone).

Lastly, practicing for the other part of the exam is an ok task, but the material is scarce. We only have three exams to work on, and one of these does not come with a solution. These exam sets are done in a few days, and after that there are no more directly exam relevant tasks to do.

Summary: The compendium is not particularily good, and there are few exam sets to work with. It is sometimes very hard to find good and relevant teaching material for many subjects, so go and ask the professor a lot. Do this from the very beginning so you don’t lag behind. This course should have a book or a rewritten compendium, as well as more directly exam relevant problems to work on.

CONCLUSION/DISCUSSION

So here comes the hard part. Concluding with something. I think AST2210 is overall enjoyable with a lot of hard work on the reports. Maybe I’m just overdoing it, but I know that several of my co-students agree. Spending 80% of the time on writing reports that account for 30% of the grade isn’t very good for what is coming considering the exam. The way this course is carried out, there should be no final exam, only reports (or home exams, call them what you want). 30% of the grade is already from reports, so I don’t see a big challenge with expanding this. 80% of the work in this couse was writing a proper report, and the grade should reflect on that.

The subject wast fragmented considering mixed messages from the professor and from the support teachers, but this leveled out. Starting out, the subject didn’t have a Piazza group, and hand-ins were all via mail. We pushed through to get a Piazza going, but the hand-ins are still via mail, not Devilry or Canvas as the rest of the university is using. I see absolutely no reason why this subject should hold back on the communications standards that most of the other subjects at MATNAT uses.

The final exam was just fine. Practicing the Kahoot questions helped a lot, and not much unexpected showed up. Mostly central parts of the curriculum were present on the exam, and it felt fair.

FEEDBACK

Please leave a comment here, or contact me at jonkd at uio dot no if you have an opinion about where I’m wrong, right, or unnecessarily condescending/mean. I only intend to give constructive feedback and some material for upcoming AST2210 students to read.