Junhua Pan

Junhua Pan is a scientist specializing in astronomical optics. Pan was born on 14 October 1930, in Wusong, Shanghai. His father, Weichen Pan, graduated from the Beiyang Navy Medical Academy. His father's former wife was Muying Fan. Junhua Pan's mother was Zhenhui Zhu, whose family operated a pottery workshop. Pan's eldest half-brother, Junmu Pan, graduated from the School of Civil Engineering, Shanghai Jiao Tong University. His second half-brother, Junzheng Pan, also graduated from the School of Engineering, Shanghai Jiao Tong University. His half-sister, Junzhao Pan, graduated from the Department of Chinese Language, Fudan University. And his brother Junqian Pan, graduated from the Department of Animal Husbandry, Beijing Agricultural University.

Junhua Pan grew up in Jiaxing, Zhejiang. When he was in grade two in elementary school in 1937, the second Sino-Japanese War began. Pan went out of Jiaxing with his family to escape from the japanese. They came back to Jiaxing in 1945, when Japan eventually surrendered. Pan enrolled at the Provincial Jiaxing High School in the summer of 1946, and then graduated in 1948.

Pan entered the Department of Mechanical Engineering in Tsinghua University, where he developed great interest in astronomy. When he was a freshman, he joined the society of astronomy, which was organized by the students in the department of physics. With great interest, he got a lot of knowledge about astronomy by self-learning, attending lectures, and making glasses. All along, he had been fascinated by astronomy, and it also became a career option. Pan earned his Bachelor of Science degree in August 1952. Because of his respect for Daheng Wang, Pan applied for working at the Preparatory Office of Institute of Scientific Instruments during the recruitment of Chinese Academy of Sciences, and then got the permission.

Pan went to work in Changchun from the mid-October in 1952. During his work in the Institute of Scientific Instruments, Pan modeled some scientific instruments as the ones in the foreign countries. These instruments were in urgent need. In 1955, Pan and his 5 colleagues in the Institute of Scientific Instruments were appointed to be disengaged from their work and learn Russian. After that, Pan was send to study in the Central Astronomical Observatory of the Russian Academy of Sciences at Pulkovo, and started his graduation work with Dmitry Dmitrievich Maksutov, a Soviet optical engineer and amateur astronomer. Maksutov was a Corresponding Member of the USSR Academy of Sciences, and best known as the inventor of the Maksutov telescope. During his first year in Pulkovo Astronomical Observatory, Pan got all the credits in the courses, including Russian, Philosophy, and the specialized courses. According to the suggestion of Maksutov, Pan pursued his research work on "The method for testing the convex secondary mirror of large telescopes". At the very beginning, Maksutov hoped Pan to get some useful findings from evaluating the Hindle test with a lot of calculations. After reading the publications of Maksutov, Pan found that Maksutov's compensation method for the control of primary mirrors of large telescopes was also suitable for the test of the secondary mirror, and this kind of method was helpful to reduce the size of the test mirror. Furthermore, Pan developed the formulas for testing large telescope and its convex secondary mirror. During that time, Pulkovo Astronomical Observatory was building PM700 telescope. Pan successfully applied his testing method to the PM700 telescope's secondary mirror, which was made by Pan himself, and proved his method. This method for testing was named as "Pan's method"by Russian.

In 1960, Pan got his Licentiate's degree and went back to work in Changchun Institute of Optics and Fine Mechanics. At that time, China was independently developing shooting range. A large aperture optical instrument was in urgent need for shooting range test. Importantly, the key and new knowledge and technology for making the optical instrument were what Pan acquired. In 1964, a cinetheodolite with a diameter of 625mm was worked out in the Changchun Institute of Optics and Fine Mechanics and showed high quality and satisfying detecting range. The employment of optics with perfect optical quality by Pan at the cinetheodolite was highly significant in obtaining the data. At the same time, Pan developed the making and testing methods for the large-aperture aspheric surfaces, and devoted to its application.

In 1975, Pan visited East Germany for the conduct agreements negotiation of one-meter aperture telescope. In 1977, he visited East Germany for checking the telescope before acceptance. Along with these activities, Pan got back to touch the astronomy academic community. The project on the 2.16-meter telescope restarted in Nanjing. According to Daheng Wang's suggestion, Pan joined this project not as an official researcher but as a travel staff. He was appointed as the instructor of technology group of the whole project and then the instructor of the Echellespectrograph for the Coudé focus. In 1980, Pan joined the Nanjing Research Center of Astronomical Instrument as a senior research fellow. He contributed significantly to the first largest Chinese-built telescope, 2.16-meter general purpose instrument, working both on its design, making, measurement and management. In 1988, 2.16-meter telescope was built up and moved to Xinlong Observatory, and immediately served for the jointly observation between Chinese and French astronomers. The 2.16-meter telescope was honored with the first class of National Science and Technology Progress Awards in 1988, and the Echellespectrograph was honored the third class of National Science and Technology Progress Awards in 1999.

Pan became involved with the design, fabrication, testing and measurement for the large-aperture aspheric surfaces from 1960s. He designed and made the large-aperture aspheric surfaces being used for reconnaissance vehicles, earth resources satellite, synchrotron radiation facility, and other important instruments. Based on the optical theory of two-mirror system, Pan also developed a set of formulas to calculate the three-mirror optical system, which was proved to be very helpful and ease of use, and satisfying the practical requirement. Moreover, Pan worked out the effective formulas for off-axis two-mirror optical system, the Yolo. His book "The Design, Production and Testing of Aspheric Surfaces" was published by Science Press in 1994, and then became very popular because it is very practical and handy of reference.

Pan retired from Nanjing Research Center of Astronomical Instrument in 1993. He was elected as the member of Chinese Academy of Engineering in 1999. He became the professor of the Institute of Modern Optical Technologies in Suzhou University. Since the increasing application of aspheric surfaces in important optical devices used in aerospace and national defense, Pan is still active in technology consulting about the key problems in aspheric surfaces.