National Astronomical Observatory of Japan

 Yukio Katsukawa

I want to channel my excitement for “HINODE” into another satellite launch.

Solar Science Observatory
Associate Professor

Yukio Katsukawa

We are just at the critical point in Japan’s contribution on a balloon observation scheduled to be launched in 2022.

We have just entered the final phase of Japan’s contribution on SUNRISE-3, a balloon-borne solar observatory that is currently under development as an international effort, and that occupies about 80 percent of my current workload. This balloon is to be equipped with a 1-m aperture optical telescope, and we are responsible for one of the observing instruments called “SCIP” (pronounced “skip”). This instrument will be assembled at the NAOJ Advanced Technology Center and then go through a performance evaluation that involves actual observations of solar light. Once these steps are completed, SCIP will be sent to Germany and go through another set of tests, such as putting the instrument in the telescope, adjusting the position, and letting light into the instrument to confirm that it can take clear images. The lift-off is two years away (in 2022), but there is still a pile of work remaining to be done.

In addition to the work at NAOJ, I try to teach some sort of classes every year at a university, for example, at the University of Tokyo in 2019 and at Chiba University in 2020. I am also involved in an activity called FUREAI (Friendly) Astronomy(note 1), visiting elementary and junior high schools to deliver a talk. Elementary school children, in particular, listen to my talk eagerly with their eyes gleaming with curiosity. Every time I use a software program called “Mitaka(note 2)” and show them a video zooming out from Earth to outer space, they shout out, “Wow!” Seeing their twinkling eyes makes me go back to my original intention … and it is an invaluable experience for me.

(note 1) “FUREAI (Friendly) Astronomy” is an educational program that NAOJ has offered since 2010, where professional astronomers visit elementary and junior high schools around Japan to deliver astronomy lectures.

(note 2) Four-Dimensional Universe Viewer “Mitaka”

Yukio Katsukawa during the interview.

Being able to communicate is a huge advantage.

In fact, I was kind of introverted originally. But when I started graduate school and got to visit NAOJ frequently, I happened to be involved in the development of the HINODE Solar Observatory, which had yet to be launched then. This project involved not only scientists of the observatory, but also many engineers, and people from outside manufacturers. I was assigned to serve as something like a liaison to manufacturers, and that was quite a task—It was so heavy that I had a bald patch here [points at his head]. People from manufacturers seemed to teach me what I should do, but in reality they did not, and I did not even know who or what to ask. Still, I struggled on for several months, until they started to come to me and teach me things such as how to use a measuring instrument, and eventually we grew accustomed to working together. I gradually became able to communicate, and this experience has had a major influence on my current work.

When I started my own research in graduate school, technical know-how was usually provided by someone nearby. Now we can obtain much information from the internet, but I want students to be able to work based on conversations. I believe it is important to interact with and learn from others, and to inform as many people as possible about our research. In this sense, FUREAI Astronomy is one of my important training exercises.

I took one-month leave when my second daughter arrived and commuted together with family members.

It has been 15 years since I came to NAOJ, and our working environment has changed significantly over the past years. Currently, NAOJ offers a generous benefits package to their employees with families, making it easier even for male employees to take parental leave. So, I took a full month of leave when my second daughter arrived. I used the childcare room at the observatory for one year. My wife also works here, and after her parental leave ended, we applied to a nursery school near our home, but were rejected. So, we decided to use NAOJ’s childcare room. I came to the observatory together with my wife and second daughter every morning, and my wife went back home earlier with our second daughter. It was pretty fun times.

I have two daughters ages six and three and have brought both of them to the observatory many times. They know that I study the Sun and also know what a black hole is. Although I do not know whether they are interested in such things, it seems that they, like me, love to create something with their hands. And they especially love “Kimetsu.” (Japanese manga series Demon Slayer: Kimetsu no Yaiba)

Yukio Katsukawa talking about his graduate school experiences.
Pinned on the wall near Katsukawa’s desk are drawings by his children and articles featuring his work.

I was impressed beyond words when HINODE sent back the first data.

It was very fortunate timing that I was able to get involved in “HINIDE” when I was a graduate student. It was launched two years after I earned my Ph.D. degree (in 2006), and I was deeply impressed when I first saw data acquired by the satellite. I was responsible for an important part that determines whether the telescope can capture clear images, so when I found that the first images(note 3) were unarguably clear, I felt excitement beyond description.

In the future, I want to launch another satellite into orbit. The development of SOLAR-C, our next solar observation satellite after HINODE, is already underway. But actually, not many of my ideas have been adopted into this satellite, so I want to realize another satellite integrating the experience and know-how I have gained so far.

Regarding my research, I would like to study not only the Sun, but other stars as well. Like our Sun, other stars have magnetic fields that trigger explosions, so I want to extend our findings about the Sun to other stars. This is what I want to address using every technique I have learned so far.

The first images from the optical telescope onboard the HINODE Solar Observatory.
The first images from the optical telescope onboard the HINODE Solar Observatory.
The first images from the optical telescope onboard the HINODE Solar Observatory.

(note 3) The first images from the optical telescope onboard the HINODE Solar Observatory. From darker to lighter, these were captured before, during, and after opening the door that protects the telescope’s optics. The blotchy pattern that starts to appear from the second image is called granulation and is produced by convection on the solar surface.

Yukio Katsukawa posing with replicas of HINODE Solar Observatory components.

Interview Date: December 17, 2020 / Published July 26, 2021
Interview & Article: Masami Usuda / Translation: Ryo Sato and Ramsey Lundock / Photo: Yutaka Iijima
With a few exceptions, the contents of this article are as of the interview date.