Sunday, 6 January 2013

Harold Zirin - Astrophysics Of The Sun

I thought it only appropriate seeing as I spend so much time observing and imaging the sun that I actually find out a bit more about it and what actually makes it tick.  So, I bought a copy of Harold Zirins classic book 'Astrophysics of the Sun.' 

This is an entirely new edition of Harold Zirin's classic text on the solar atmosphere. Combining an introductory course in astrophysics with a comprehensive treatment of the theoretical and observational aspects of our present knowledge of the sun, the book has been completely updated. It includes a large number of spectacular new photographs, including many of the best solar pictures from the world's observatories. Professor Zirin was one of the leading scientists in his field. His lucid writing style, combined with considerable teaching experience, has resulted in a valuable and important textbook of astrophysics.  Whether you are a beginner or experienced astronomer, amateur or pro, this book contains something that you don't know about the sun. It is perhaps the most complete source on solar astonomy available. It is written in a very "academic" style because it is intended for astrophysics graduate students and researchers, but it can be read by advanced amateurs who are not afraid of mathematical formulas. Sadly Professor Zirin died in January 2012 however his ifluential text lives on.  Here follows his obituary from the BAAS:

Obituary: Harold Zirin (October 7, 1929 - January 3, 2012)

Dr. Harold Zirin, an emeritus professor of astrophysics at the California Institute of Technology, died on January 3, 2012, in Pasadena after a long battle with debilitating chronic obstructive pulmonary disease (COPD). His passion for solar astronomy led his undergraduate students in the 1970s to produce a comic book of him as an unassuming professor who became the super-hero “Captain Corona” whenever he stepped into a solar observatory.

Hal was born in 1929 in Boston to immigrants from Russia and the Galician region of eastern Poland; he grew up in Bridgeport, Connecticut. Hal liked to recall that he had come a long way from helping out as a youngster on a chicken farm in New Jersey. His childhood interest in astronomy was aroused by a view of the moon’s craters and mountains through a young friend’s telescope. Hal’s precocity, and a telescope that he built, won him a Westinghouse Talent Search Prize and a Pepsi Cola Scholarship for Connecticut in 1946. These achievements came to the attention of the astronomer Bart Bok, who attracted him to Harvard where he stayed through completion of his Ph.D. in 1953.

After graduation, Hal worked briefly at the Rand Corporation in Santa Monica, CA. But his career there was cut short by failure to obtain security clearance because his father was a member of the Communist Party. Instead, he returned to Harvard as a teaching fellow and in 1954 he joined the High Altitude Observatory in Boulder, Colorado, a center for solar studies. There, George Gamov introduced him to Mary Fleming,and they were married in 1957.

Mary recalls how, in 1960-1961, she and Hal traveled by car to the Crimean Astrophysical Observatory, in perhaps the first scientific exchange with the U.S. that the Soviet Union permitted outside major cities. There, the six months of hands-on experience with solar telescopes and instrumentation convinced Hal of the importance of continuous solar observations at high angular resolution. This fruitful conviction was one of the most important lessons Hal passed on to students and post-docs who worked with him in later years.

In 1964 Hal accepted a professorship in astrophysics at the California Institute of Technology. A search of varied sites for high resolution solar observations was undertaken with the support of the noted Caltech physicist Robert Leighton. Reputedly, after careful measurements all over Southern California, the steadiest air was found in the Caltech parking lot! But the observatory site was chosen high in the San Bernardino mountains on the north shore of Big Bear Lake. There, steady air over the lake combined with clearer sky, promised observations even of faint structures in the sun’s outer, coronal atmospheric layers.

Hal was a born entrepreneur and with a small grant from Caltech and additional funds from the Fleischman Foundation, he built the Big Bear Solar Observatory (BBSO) and its support facilities. He also led solar-astronomy research at Caltech's Owens Valley Radio Observatory (OVRO) and developed that observatory's solar interferometer. Observations of the amazingly detailed solar structures from BBSO and OVRO produced many interesting insights into solar magnetism, flares, and magneto-hydrodynamic waves. In the 1960’s Hal’s fascination with the sun’s detailed structure was ahead of its time and, in some circles, this earned him a reputation as a “solar dermatologist.” Since then, all solar astronomers have come to recognize the importance of understanding solar phenomena at the smallest observable scales.

Hal’s achievements attracted an international group of students and post – docs, many of whom went on to make important contributions to understanding of the sun. At regular lunches he organized with solar researchers in the Caltech physics department and at nearby Carnegie Observatories, the sometimes more measured research approach of these colleagues complemented Hal’s ebullient style to produce valuable insights into the workings of our star.

In hopes of achieving full time coverage of rapidly evolving solar phenomena, Hal travelled in the 1970s from northern Sweden to the Negev Desert in Israel, where for some time he ran a solar telescope in cooperation with Tel Aviv University. Later, scientists trained at BBSO created successful solar observatories on lakes in India and China. Hal also mounted solar eclipse expeditions in Ceylon (Sri Lanka) in 1952, in the southern jungle of Mexico in 1970, and in Hawaii in 1991.

Hal’s broad knowledge of the sun is laid out in over 250 scientific papers and in his widely used texbook Astrophysics of the Sun (2nd edition, 1988). Unfortunately, increasing hypoxia prevented him from completing the third edition.

Harold Zirin’s generosity, intellectual capacity and energy will be greatly missed by all who were fortunate to work with him. He is survived by his wife, Mary Zirin, a free-lance translator-researcher in Russian literature; a son, Daniel Zirin, of Hastings Ranch, Colorado; a daughter, Dana Haigney of Altadena, California; and two grandsons: William and Jacob. The family asks that donations be made in Zirin’s name to National Jewish Health in Denver, Colorado.