UofL Students Examine the Sun in Hands-On Physics and Astronomy Course

By Stephanie Godward, Communications and Marketing Director, College of Arts & Sciences 

Physics students recently captured images of the Sun with new portable Seestar telescopes, collecting data while getting experience in observational astronomy outside of the classroom. 

Physics Professor Benne Holwerda is teaching PHYS 308 Observational Astronomy for the first time this fall with six of the new telescopes, which are equipped with solar filters and controlled through a smartphone.  

The telescopes allow students to collect images and data while experiencing firsthand both the possibilities — and unpredictability — of observing the natural world. 

“The idea is to teach physics and astronomy students what it's like to observe, and then do something with the data,” Holwerda said.  

Unlike an experiment conducted under controlled laboratory conditions, astronomy requires students to work with whatever nature gives them. Clouds can roll in, weather can change, and equipment can malfunction just as conditions become ideal – all realities of the research process. 

“You're completely weather dependent,” Holwerda said.  

The class began its observations during the day by turning its telescopes toward the Sun. The timing has given students plenty to see: Holwerda said the Sun is on the tail end of solar maximum, providing numerous sunspots for students to observe and count.  

NASA explains that sunspots are cooler regions on the Sun caused by a concentration of magnetic field lines. Sunspots are the visible component of active regions, areas of intense and complex magnetic fields on the Sun that are the source of solar eruptions.   

The exercise connects their observations to a much longer scientific record. People have been counting sunspots for roughly 300 years, Holwerda said, and students can place their own counts within that history. 

But creating striking images of the Sun is only the beginning. 

“The idea behind the lab is that they take the actual data and then infer something — and do actual physics with it,” Holwerda said. “It comes up with beautiful JPEGs and it can do really nice photography, so it's a very powerful telescope.” 

Students are also using sunspots to observe something they cannot see simply by looking at a single image: the rotation of the Sun. 

With the help of an image taken by the course teaching assistant approximately a day before or after the students' own observations, students can compare the position of a sunspot across roughly 24 hours. From that change, they can determine how much the Sun has rotated. 

“So there's like a before and after,” Holwerda said. “They can compare 24 hours and see how much the sunspot has moved and see how much the Sun rotates.” 

The Seestar telescopes also make observational astronomy more accessible than a traditional telescope. Rather than requiring users to look through an eyepiece and manually locate an object in the sky, the instruments communicate with a phone and can automatically find an object selected by the user. 

“You basically say, ‘I want to look at the Sun,’ and it goes and just looks at it,” Holwerda said. 

That ease of use allows students to spend more of their limited observing time collecting and working with data — and gives them an opportunity to experience the process of scientific discovery themselves. 

Later this fall, students will have the chance to observe the Moon and also have visited Moore Observatory to complete other astronomy projects. 

For Holwerda, that is central to the course: giving students manageable observational projects in which they can gather evidence, analyze it, and use it to answer a real physical question. 

And along the way, students are learning that astronomy involves more than knowing what is in the sky. It means figuring out how to observe it, working around the conditions nature provides, and turning what they see into data that can tell them something about how the universe works.