Memories of Katsuo

The Astronomical Herald, Astronomical Society of Japan, 1990 July issue

In 1971 Prof. Z.Suemoto wrote me that he would like to send me his student, the outstanding young solar physicist in Japan, Katsuo Tanaka. He came to Caltech as research fellow and worked in our group from July 1971 to March 1973. I soon found that I had gotten a tiger by the tail. Katsuo was not only smart, he was full of energy, constantly exploring new ideas and new directions. We immediately hit it off; he shared my feeling that we could learn a lot about solar activity by observing the grand patterns with the highest possible resolution. But he had more energy than I did, and carried out his studies with deep detail and care. I would often find him in the film room late at night or on weekends, intensely analyzing some spot or another. He had an artistic gift, too, with the ability of making accurate detailed drawings of the complex Hα structure that had filtered out the information from the movies. He took the data and carried out sophisticated analyses, such as his work on the force-free fields with Nakagawa. He was not only focused on solar activity; together with Bhatnagar, he carried out detailed measurements of the oscillations in Hα which still stand as an important key to that subject. He made high resolution observations of spicules that showed they often are doubled. Others doubted this, but subsequent observations showed that he was right. I was sorry to see him leave Pasadena, though I knew he had important things to do in Japan.

Subsequently he was Visiting Associate at Caltech in 1975, 1977, and 1986. We collaborated on several papers and many projects. All through these years we maintained close intellectual contacts. We seemed to be worrying about the same problems, so that when we met in Japan or here, we seemed to be continuing the same conversation. And we always needed to share what we had accomplished and get the other's approval. We were always so happy to meet, especially if we could look at solar movies together.

During their stay here and visits to Japan, my wife and I got to know his family, his lovely wife Chisako and the two charming girls Kaoru and Sanae. Gradually the barriers of formality broke down and we became close friends. Katsuo was one of the finest human beings I have ever known.

Whoever decided to put Katsuo in charge of Hinotori was smart. He combined the unusual characteristics of a person who understood instruments, but also who understood what science was needed. He did not just study X-rays because it was interesting, but because he had a definite idea what was sought. After the successful conclusion of a project, some experimenters follow the natural tendency to breathe a sigh of relief and go back to their labs; Katsuo dove right into the analysis; he couldn't wait to find the answers. His broad approach: experiment, observation, theory, and his beautiful sketches, should be an inspiration to all.

When he learned the true nature of his disease, he characteristically attacked it with his great energy and spirit. As you know, he survived two or three times as long as the average person with this type of leukemia. He kept a long chart with a plot of his white blood-cell count, as objectively as one might keep the brightness record of a flare. Each time a new medicine was tried he marked this with an arrow, we would see the count drop, then inexorably rise again.

Before Christmas he wrote me a long letter, telling me his situation, telling of the papers he was writing, and of his plans for other papers. He worked on scientific problems to the very end. On the day after he died I received a handwritten letter from Tanaka, a letter, so to speak, from the other world. He enclosed with it the manuscript of a paper he had completed, which I was to edit for a Big Bear preprint. That paper will appear, but we will never see the other papers. We will truly miss him.

Hal Zirin (Big Bear Solar Observatory, CALTECH)