News

December 20, 2007

Observing the Sky

Greg Davis ’08 discusses his experiences in Prof. Michael Stark‘s course, Observational Astronomy

Greg Davis ’08 is a physics major. This semester he took the course Observational Astronomy with Michael Stark, assistant professor of physics. The following is a first-person account of his experiences.

  • Students Participate in Hands-On Astronomy

There are many expectations that students have when coming to college, and with a little bit of effort, they can be fulfilled. One such expectation I had was that a liberal arts college should broaden the horizons of its students, even if you are a physics major like I am.

Observational Astronomy has allowed me to do exactly that. Ever since my sophomore year in high school, I have taken photography classes, worked as a photographer’s assistant in a studio, and been hired as a photographer. However, there are many more interesting and useful ways to use photography than anything I had done prior to Observational Astronomy. Since the class was small, only two students this semester, it allowed Professor Stark to be very flexible in the material taught.

Coming in to the class I knew basically nothing about astronomy or techniques used to observe what is outside of our planet. The emphasis in class was not to labor through problems, but rather to understand how astronomers obtain information. By the end of the semester, we observed the sky using everything from the naked eye to the radio telescope on top of the science building.

Now how has photography managed to become incorporated with what we have done? By using a simple adapter connected to my dSLR (a camera used by most photojournalists), I connected my camera to a telescope. By taking long exposures, the camera was able to resolve what is too faint for the naked eye to see. All of a sudden, nebulas, faint stars, etc. were visible. It was amazing how much is out there that your eyes cannot see, but a camera can.

Professor Stark was eager to help me actually do astrophotography myself and was just as excited about the possibilities as I was. Not only did we use my dSLR to observe, but the physics department also has an astronomical CCD (a sensor found in dSLRs for image detection). By using different color filters, the CCD can observe specific wavelengths at a time. With these photographs, we can categorize stars by size. Through compiling three filtered photographs taken by the CCD, we formed a color image and had a more accurate representation of what we were observing.

Now the class was not only about using photography alongside astronomy. We also worked on a lab that I was never expecting: observations of the sun. Professor Stark ordered a few lenses over the summer and a fiber optic cable. We mounted the lenses on a telescope stand and then connected the lenses to the fiber optic cable. This fiber optic cable was then connected to the spectrometer in a physics lab. The spectrometer was connected to a computer to measure and graph the intensity of light at different wavelengths.

By running this experiment twice and directing the lens at each side of the sun, we could calculate the rate of rotation of the sun through the Doppler shift. The Doppler Shift is the effect of how the measured wavelength of light changes as velocity changes. For example: If a car is coming toward you and honking its horn, it sounds like a higher pitch than it does when the car is traveling away from you. Just as with sound, you can measure this effect with light and the color will be different on each side of the sun (one side is rotating away, and the other towards you) since the wavelength and frequency appear to change.

Needless to say, Observational Astronomy has been one of the most interesting electives I have taken so far. There is an endless amount of sky out there to be explored, and through the techniques I have learned I have been able to have an intimate learning experience while having the class catered to my interests. I could not have expected more.

  • Physics

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