Astronomy 392J
Astronomical Instrumentation

Fall 1999, TTh 9:30
RLM 13.112

Professor Daniel Jaffe
Department of Astronomy, The University of Texas at Austin, Austin, TX 78712


Contacts

Prof.- Daniel Jaffe, RLM 17.218, 471-3425, dtj@astro.as.utexas.edu
TA (machine shop supervisor)- Greg Doppmann, RLM 16.308, 471-3453, greg@astro.as.utexas.edu
Machinist- Jimmy Welborn, RLM 17.330, 471-3427, jimmy@astro.as.utexas.edu
Substitute Prof- John Lacy, RLM 16.332, 471-1469, lacy@astro.as.utexas.edu

1. Introduction

This course teaches the fundamentals of the design and construction of experimental apparatus using astronomical instruments as the model for the process. We will cover key aspects of some of the most important topics in the field: optics and optical design, mechanical design and machining, electronics design and fabrication, real-time computer control, project planning, and performance analysis. Since we cannot teach you everything you need to know in a single semester, we will try to equip you with enough background to be able to continue learning on your own.

1.1 Overall Objectives

By the end of the course, you should have a concrete knowledge of many of the essentials of instrumentation. You should be able to plan out, schedule, and organize an instrumentation project and have some idea of what goes into a project budget. You should understand the steps involved in the mechanical, optical, software, and electronics design. You should have a good working knowledge of where to obtain information you need for your project in each of these areas. You should have concrete knowledge of computer aided design (CAD) programs for mechanical design (AutoCad), electronics design and simulation (Circuit Maker), and optical design and simulation (Zemax). You will know how to do basic work with hand tools and with machine shop equipment. You will be able to assemble and understand some electronics circuits and be able to use laboratory equipment to test them. You will know the fundamentals of optical design and be able to design and build a grating spectrometer. You will be able to use LabView to interface an instrument to a computer.

2. How the Course Works

2.1. Philosophy

Astronomy 392j is a team-taught course where you are part of the team. There will be only occasional classes in a more conventional seminar/lecture format. Most of the rest of the time, the class will look more like an apprenticeship, an engineering project course, a physics lab course, or a bunch of curious kids let loose in a room full of great toys. The learning in this course is centered around the activities of teams of 3-4 students. We have structured the activities to emphasize collaborative learning. As future teachers, researchers, and technical managers, you will need to know how to help colleagues, coworkers, employees, and students master complex material. You will start that process here. Your participation as a teacher/trainer in this course is as important as your role as student/trainee. You will be encouraged to work together on almost everything. Although there will be some background reading to do, most of the learning will take place in the form of activities. Compared to the typical course, this course will involve much more ``class'' time and somewhat less time outside of class. We encourage people to make themselves available to their peers by spending some extra time in the lab. We have set aside general space to allow you to work together on problem sets. Feel free to hang out, but be ready to give up your space if a working group or team needs it for some reason.

As professor for this course, I serve four purposes: (1) As facilitator. I am here to make sure you have all resources necessary to do the activities and learn the material. This includes making sure the software works, the hardware is there, the materials are clear etc. (2) As part of the coaching staff. Along with the other members of the Department and the Observatory who are making themseleves available, I am (in principle) a knowledge resource. You can come to me for advice, for direction to additional people or material, or for help when you are flat-out stuck. (3) As referee. When there are conflicts between or within teams and groups over resources or (heaven forfend!) personalities that cannot be resolved satisfactorily without help, I am there to deal with them. (4) As evaluator. This is after all a course. You will get a grade (see below). I also take seriously the part of this role that involves evaluating the course materials and organization, as well as the performance of the outside instructors and even ourselves. Y'all need to contribute to this effort by taking your own evaluating role seriously.

2.2. Texts

Building Scientific Apparatus by Moore et al. (2nd ed)

The Art of Electronics by Horowitz and Hill (2nd ed.)

Both of these are great references as well as textbooks. If you have any inkling at all that you may be around instrumentation in the future, hang onto these books at the end of the semester!

2.3. Segments and Segment Groups

The curriculum for this class has been divided into four segments. Each segment covers an important aspect of instrument design and construction: mechanical design and fabrication, electronics and circuit design, optics and optical design, and computer interfacing and software design. The segments will consist of a reading assignment, a set of problems, some hands-on skill learning tasks and a laboratory exercise.

The class will be divided into segment groups. Each group will rotate through the segments in succession. Groups will have 3 weeks to complete each segment. You will do most of the activites as a group.

2.4. Projects and Project Teams

A major aspect of this course will be the use of what you are learning to design and construct a working instrument. The instrument project for this year's class will consist of designing and building an optical spectrograph. This instrument will have a solid-state optical detector and operate under computer control. It should be able to take wavelength-calibrated spectra of bright emission-line sources (lamps).

You will carry out the project as a member of a project team. Each team will be responsible for planning, designing, and building its own instrument. The members of your team will all come from different segment groups so that your team quickly collects all of the skills needed to carry out the project.

1. Assignments and Deadlines

Each segment will have a reading assignment, a set of paper exercises, a piece of software to master, a practical exercise, and an evaluation/debrief. Because other groups will need access to the hardware, your group must complete each section within the allotted time. The evaluations should be done individually and handed in to the instructor. You should work out the paper exercises or problem sets on your own. You may then consult with your group about the answers. Each student must hand in his or her own writeup of the problems. Problem sets will be due at the end of each segment (note that, for the computer interfacing segment, you will need to demo your knowledge rather than doing a problem set). Each project team will have a preliminary review of their design and a final review of the project. At the two reviews, each member of the team will be expected to be able to stand up and make any part of the presentation. At the preliminary review, approximately six weeks before the end of classes, each team member will have to turn in a written description of the instrument, how it will work, and how it will be built. This document should be about two pages long, plus figures.

2.6. Class Meetings

In order to transfer information between the groups and teams and between these entities and the instructors, to settle scheduling conflicts, and to provide an opportunity for making adjustments in the material, we will have a brief class meeting each TuTh at 9:30 (promptly!). Parts of some classes will be devoted to a class lecture/activity on an instrumentation topic. The remaining time will be used for meetings of groups and teams, together with the Prof. Attendance at the meetings is a course requirement.

2.7. Getting Help

(a) Your Segment or project group: You are all working together, so split up the learning task in a way that makes sense to you and then teach each other what you know.

(b) Your classmates: Many of you come into this with a great deal of knowledge and talent. Make it your business to find out which of your classmates is already an expert in something and tap into that expertise.

(c) The Prof : I will arrange meeting times with each group and team outside of class time. Apart from that, it you need to meet with me, have a member of your group arrange a time for me to be here when your group or team is. Personal problems of individual students can be handled in my office, by arrangement.

(d) Other experts: One advantage in being in a place where a lot of building is going on is that somebody usually knows the answer to your question. I will be calling on some of the local experts to share their expertise in certain areas and to serve on the design reviews for your projects. Sometimes, these folks can be helpful before you get to that stage by getting you started on something, giving you a reference, or telling you your idea won't work. These folks can be found on the 15th to 17th floors of RLM. Here is a partial list.

Optics: Phillip MacQueen, Bob Tull, Gary Hill,

Electronics: Phillip MacQueen, Gary Hansen, Fred Harvey, Al Mitchell

Computer Interfacing: Mark Cornell, Bill Spiesman.

Mechanical Design: John Booth, Gordon Wesley, George Barczak, Jimmy Wellborn

(e) (Heaven Forbid!) A book. There are tons of books out there. Some of them are even helpful. Also, check out parts catalogs. They often have little tutorials in them. The parts themselves sometimes give you ideas. Individual segments will contain some specific references to relevant reading material.

2.8. Evaluation of Your Performance

The grade in this course should reflect the amount of skill you acquire and the strength of your contribution to the efforts of your group to learn the material and your team to build the instrument. Items we will include in setting your grade are: (1) Attendance in class time and meetings with instructor, participation in these activities (~ 15%) (2) Individual problem sets and group writeups
(~ 25%) (3) The completeness, thoughtfulness and insight displayed in your evaluations of the segments and the project (~ 10%) (4) Your writeup of the instrument for the preliminary review (~ 10%) (5) Your performance and that of your team at the preliminary review (~ 10%) (6) The level of mastery you display when you (individually and as a team) exhibit and demonstrate your instrument at the end of the course (~ 30%). To carry out this last point, during the last week of class, your team will demonstrate your instrument. Each of you will have a private discussion with the prof. and TA in which you explain the workings of the various elements of your system. Your evaluation on item (6) will depend equally on how well your team did on the project, and on how well you do yourself.