Ay105 (2016-2017) 

Optical Astronomy Instrumentation Lab, spring term 2016-2017

10 units (0-6-4); third term. Prerequisite: Ay 20. An opportunity for astronomy and physics undergraduates (juniors and seniors) to gain firsthand experience with the basic instrumentation tools of modern optical and infrared astronomy. The 8 weekly lab experiments are expected to include photometry measurements, geometrical optics, polarimetry, spectroscopy, interferometry, optical and infrared detector technologies, basic telescope operations and data reduction, adaptive optics, optical aberrations, coronagraphy and high contrast imaging.

Instructor: Dimitri Mawet [146 Cahill, x1452].

TA: Yuguang Chen.

Class schedule: Wednesdays 6:15pm-9:45pm, Thursdays 12:00pm-2:30pm.

Logistics: Class begins with a short lecture in 219 Cahill, after which we move down to the lab in 29 or 15 Cahill (basement level).

Office Hours: by appointment.

Class requirements:

The class is 10 units, with 6 units in the lab. 

  • Labs 35%: presence during the warmup lecture, and participation during the labs is mandatory. Conduct the experiment in teams of your peers during the allocated hours.
  • Notebook 65%: standard Caltech collaboration policy, you may discuss the lab notebook with your classmates but you must maintain your own independently. You should not spend more than 3-4 hours on the analysis and write-up. Unpolished, but COHERENT and CLEAR write up is perfectly acceptable. 
  • Lab notebooks due on Mondays at 12pm (Dimitri Mawet’s mailbox, Cahill 2nd floor). Available for collection on Tuesdays at 5pm.


Week 1 (only Thursday 4/6, 12:00pm): introduction, good practices, visit of the labs (Cahill 219)

Introduction material: here.

Week 2 (4/12, 4/13): radiometry, photometry, intro to geometrical optics (Cahill 219, then B129)

Instructions can be downloaded here
Introduction material: here.
Notebook exceptionnally due on Friday at 12pm. 

Week 3 (4/19, 4/20): spectroscopy (Cahill 219, then B129)

Instructions can be downloaded here
Introduction material: 

Week 4 (4/26, 4/27): polarimetry (Cahill 219,  then B129)

Instructions can be downloaded here
Introduction material: here.

Week 5 (5/3, 5/4): interferometry/LIGO (Cahill 219,  then B129)

Instructions can be downloaded here
Introduction material: here.

Week 6 (5/11): Optical and infrared detectors, post-processing and telescope operation
!!! CHANGE of SCHEDULE due to weather conditions !!!

Thursday 5/11, 12:00pm to 2:30pm: introduction to optical and IR detectors (R. Smith, confirmed).
(Cahill 219)

Thursday 5/11: 9pm to 12am PDT
Bonus: we will start the calibrations at sunset (7:45 pm PDT)

(Cahill 219, then rooftop observatory)
Instructions can be downloaded here

Week 7 (5/17,5/18): introduction to adaptive optics (Cahill 219, then basement 115)
Instructions can be downloaded here.

Week 8 (5/24, 5/25): optical aberrations (Cahill 219, then basement 115)
Instructions can be downloaded here.

Week 9 (5/31, 6/1): two parallel labs, two groups (look for assignments by e-mail)

Meeting time, location: 9 pm in Cahill 219, Wednesday and Thursday

Telescope, part II: download instructions here 
Wednesday 9pm-12am, Group 1
Thursday 9pm-12am, Group 2

Coronagraph lab: download instructions here, and introduction material here
Wednesday 9pm-12am, Group 2
Thursday 9pm-12am, Group 1

Important Things to Keep in Mind

While performing the experiments, some key concepts to keep in mind are: the importance of careful optical alignment, the manifestation of physical principles in the reality of lab setting, and the need to log measurements and estimated sources of error as well as the amplitudes in those errors. In addition to understanding how to set up and do the experiments, an important part of any laboratory class is the analysis, interpretation, and discussion of the lab in a written lab report. Each person must keep her/his own lab notebook. For each experiment you may have notes from the lab work, but then you must also produce a more formal description of the experiment, beginning-to-end.

How to Approach Lab Reports
When you are writing your report, it helps to keep the would-be reader in mind. If you imagine that your report is going to be read by a somewhat incompetent physicist trying to duplicate your resuls, it will help guide your thought process: the reader has some physics background (so you don't need to explain the obvious) but is prone to error (so you need to be clear, unambiguous and point out sources of error!).

Be complete, clear, and organized!

Structure of a Lab Report

I. Introduction

State the purpose of the experiment and explain, briefly, how will it be addressed with the equipment (typically half a page or more).

II. Equipment

Describe what equipment was set up, and why. Don't just transcribe the lab handout, but accurately describe the equipment used. Do sketch the layout. You should have enough detail to allow others to repeat your experiment (or for you to figure out what went wrong if something goes awry!)

III. Measurements

Describe what measurements were made, including uncertainty estimates whenever possible. Check your measured values against expectations. Make sure your error estimates are reasonable. As in all real experiments, things often do not go according to plan. Equipment may not perform properly or unforeseen snags may arise. Describe any such problems and discuss what steps were taken as a result.

IV. Data Analysis

Discuss how you converted your raw measurements into meaningful results, showing relevant equations and calculations. Show tables and plots when appropriate, paying attention to axis labels and explanatory captions. Answer any embedded questions in the lab description and instructions. Discuss sources of error, and quantify measurement errors in your end results, paying attention to significant digits. Clearly state your conclusions.

V. Interpretation & Discussion

What do your results mean? Discuss any unexpected results and try to explain them. What might you do differently the next time, and how could the lab be improved? Also, include a brief discussion of what you learned.

VI. Summary & Conclusion

This should refer back to the introductory material and summarize your results relative to your expectations.

Useful Texts
Schroeder, D.J. (2000), Astronomical Optics
Rieke, G. (2003), Detection of Light
Howell, S.B. (2000), Handbook of CCD Astronomy
Glass, I.S. (1999), Handbook of Infrared Astronomy

Useful Links
Optics 101 from Edmund Optics
Applets illustrating basic concepts relevant to this class.
Fundamental Optics and Lasers from the Melles Griot company
Intermediate Telescope Optics
CCD detector overview.
Infrared astronomy and detector overview

© Dimitri Mawet 2017