First Person: PDS Training at the World’s Largest Radio Telescope

By: Luyao Zou (Widicus Weaver Group)

The opportunity to use a radio telescope–a gigantic steel instrument that receives messages from deep space–is one of the many reasons I chose to step into the interdisciplinary field of astrochemistry. When I joined the Widicus Weaver group at Emory, I got a chance to go to the Single Dish Summer School in Puerto Rico at the Arecibo Observatory. The summer school was hosted by the National Astronomy and Ionosphere Center (NAIC) and the National Radio Astronomy Observatory (NRAO). Professional Development Support (PDS) funds from Emory’s Laney Graduate School made this trip possible.

Click here to view a group photo of summer school participants on the NAIC website. Luyao Zou is pictured center front in a blue Emory t-shirt.

Arecibo is by far the largest single dish radio telescope in the world, excluding the 1640 foot FAST in China that is still under construction. It sits inside a karst sinkhole on the Caribbean island of Puerto Rico. Its 1000 foot dish collects a dramatic amount of radio waves. The radiation feeds into a movable dome in which a secondary dish further focuses the radiation into radio receivers. Arecibo is both a passive radio wave collector and an active radio radar. The radio waves come from various sources in deep space, such as galaxies, pulsars, and molecular clouds, and from the echoes of radar signal from the planets and asteroids in our solar system.

Group Discussion. Photo by Luyao Zou.
Group Discussion. Photo by Luyao Zou.

In the week-long camp, I was immersed in a series of intense courses talking about every aspect of radio astronomy from the fundamental theory to engineering to observation procedures to data analysis. While trying to understand so much science in such a short period of time was stressful, it was also a lot of fun to work, discuss and learn together with about a hundred fellows from around the world. We had plenty of time free for discussion after each day’s workshop. People liked to gather around the pool in the observatory, enjoy food and drink, and talk about science, as well as share fun stories with each other.

Team work. Photo by Luyao Zou.
Team work. Photo by Luyao Zou.

Two experiences provided during the summer school stand out. One was a hands-on observing project using either Arecibo or the Green Bank Telescope (GBT) to practice what we learned from the workshop. GBT is a NRAO facility that has a telescope that is smaller in size than Arecibo but operates at higher radio frequencies. Unfortunately, on the day I was assigned to the hands-on project, Arecibo encountered a little mechanical problem that suspended its operation . But I was able to sit in front of a computer terminal with my teammates, remotely operating GBT 1600 miles away in West Virginia. We sent off commands to point the telescope at the desired area in the sky, controlled the telescope to track the sources, and integrated signals emitted from hydrogen nuclei dropping from a higher energy state onto a lower energy state. We observed a few galaxies and were able to estimate their size and mass from the spectral line of hydrogen nuclei we collected.

The other fascinating activity was a platform tour on to the arms and dome of Arecibo. It was so scary to look down from an arm hanging in the air 300 feet above the main dish! When the tour approached the dome where the radio wave reflected from the main dish is further focused and sent into the receivers, I could see the giant antenna feed and horns closer than I could have imagined before.

Tour on to the Arecibo platform. The dome is at the end of this arm. Photo by Luyao Zou.
Tour on to the Arecibo platform. The dome is at the end of this arm. Photo by Luyao Zou.

Tropic thunderstorms were unpredictable on site. The rain fell before it went dark, and then the water vaporized back into the air. The atmosphere was humid after the rain, and fog rose and started to accumulate in the dish after midnight. From the control room, the dish appeared like a giant pot stewing porridge. The fog persisted in the rain forest until the finger of the sun broke the dawn.

Arecibo in the dawn mist. Photo by Luyao Zou.
Arecibo in the dawn mist. Photo by Luyao Zou.

I had been thinking about taking a photo of the telescope with the starry night as the background. But the rains and fogs every day had stopped me from doing that. Fortunately, I got my chance to take the photo I wanted during the last night of the workshop. That night we had a nice farewell banquet under the beautiful sunset and twilight. Then the sky cleared out; no clouds and no moon before midnight. I went down to the bottom of the Arecibo dish with my camera and tripod, found a spot that had an open view of the sky, and started taking photos one after another until a few hours later when I ran out my battery. By that time, the moon had risen up to the top of the sky, and clouds had accumulated. I had fully used my photography time window, and what I obtained was one astounding picture from a synthesis of about 100 single shot pictures of the telescope.

Star trail at Arecibo. Photo by Luyao Zou.
Star trail at Arecibo. Photo by Luyao Zou.

After the summer school, I took the opportunity to stay in Puerto Rico for a few days. In Old San Juan, I walked by local townhouses painted in rainbow colors through alleys covered by cobblestones. In Fajardo, I was able to kayak through a/the mangrove forest into the renowned fluorescent bio-bay, where the magic microbes in the sea water fluoresced around my kayak and paddle.

All these extraordinary experiences could not have happened without the financial support of PDS training funds. The PDS program at the Laney Graduate School at Emory provides students with the resources to embrace the excitement of travel, learning, and academic research through experiences like mine.

Disclaimer: My personal travel costs in Puerto Rico after the Single Dish Summer School were not  covered by PDS.

 

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