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Dear friends,
I really enjoy starting these newsletters with good news. Larry Lesyna heard about our SETI course and volunteered his help in assisting with course development. He sent me a course syllabus that he had drafted about a year ago, and we exchanged a few emails. Larry is a former SETI researcher who worked on the NASA SETI endeavors, and he believes that a SETI course can be of great value to students. Earlier this week, I learned that Larry had used our web site to make a generous donation in support of increasing student exposure to SETI. I am very grateful for his support and am excited to work towards the vision that he, Janet Marott, and I share.
The UCLA SETI course is now in full swing, and I am thrilled about the students' engagement and progress in the course so far. The first session was devoted to a lecture on radio astronomy fundamentals, including source brightness and flux, antenna beam patterns, receiver sensitivity, and the radiometer equation. Our lecture/computer room has four projectors and white boards, and I used all of these resources to highlight key points. The second session started with an explanation of celestial coordinates, followed by a computer programming task that the students tackled in small teams. I explained that they would be designing an observing program the following week, and that it was critical to figure out whether sources would be observable (e.g., above the horizon) during our observing window on April 15. I asked the students to write a computer program that converts between celestial coordinates (right ascension and declination) and horizon system coordinates (azimuth and altitude). They could either solve the problem the hard way (with a combination of matrix rotations) or the easy way (by calling existing libraries from their computer program). Some students had never written a program before, and others had quite a bit of experience with writing code. Most teams chose Python as their programming language. It was quite gratifying to see several students report the correct answer before the end of the session. This course concept really works: students are learning something new and useful, and they are motivated to learn it because it is framed in the engrossing context of SETI.
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Students in the UCLA SETI course design an observing program.
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During this past week's sessions, the students designed an observing program for the Green Bank Telescope (GBT). They are familiar with the basic parameters of the GBT because they had to compute beamwidths, telescope gain, and data rate for the first problem set ("Getting to know the GBT"). The students worked together to figure out the center frequency of observation (1400 MHz), bandwidth (several hundred MHz), and known beacons that might be useful in testing their software later (e.g., pulsars, spacecraft carriers). Then, they were back on the computer to figure out the local sidereal time corresponding to our observing window and the part of the sky that will be accessible to us. Yesterday they searched through a pulsar catalog to identify a pulsar with desirable properties, and several students independently came to the same conclusion (B0329+54). A student proposed observing a geostationary satellite, and another student proposed observing a GPS satellite. GPS satellites emit signals at frequencies that we can detect (1227 MHz, 1381 MHz, 1575 MHz), but they make two complete orbits per day, so it is important to identify which satellite(s) will be visible by the GBT during our observing window. Several teams wrote a Python program that reads orbital elements and computes satellite positions. We identified several observable GPS satellites, but we will exclude those that are no longer operational. The pseudo-random noise (PRN) sequences transmitted by GPS satellites are very similar to those used in some planetary radar applications, so their spectra will look very familiar.
Towards the end of yesterday's class, students proposed a number of exoplanets and exoplanetary systems that we may want to observe this Friday. This brainstorming session resulted in a list that requires some filtering and ordering, in part to minimize the amount of time that we spend repositioning the telescope. This weekend, I will draft an organized sequence of sources based on the suggestions that we wrote on the board and other suggestions that students are submitting by email. This Wednesday, we will review the entire observing plan together, and on Friday, we will observe remotely with the GBT!
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The white board at the end of yesterday's class included possible parameters and sources for our upcoming observing program.
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Warm regards,
Jean-Luc Margot
P.S. I hope you like the new mailing list management system that I am now using to send the SETI newsletters. This new system is easier to manage and provides a nice archive of previous newsletters. I took the liberty of importing your email address into the new mailing list.
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