Harold Lester Johnson
Harold Lester Johnson (born April 17, 1921 in Denver , Colorado , † April 2, 1980 in Mexico City ) was an American astronomer. He developed methods for the precise measurement of the brightness of stars and other celestial objects.
Johnson went to school in Denver, where he studied mathematics to graduate with a bachelor's degree in 1942. During World War II, he helped develop the radar . After the war, he studied astronomy at the University of California, Berkeley, and completed his doctoral thesis on electronic equipment for measuring photo plates in 1948. This began a lifelong preoccupation with methods for precisely measuring the brightness of celestial objects.
In 1948 he moved to the Lowell Observatory in Flagstaff , and after a short stay, at the end of the year, he continued as an assistant professor at the Washburn Observatory at the University of Wisconsin in Madison . From 1950 to 1952 he was an assistant professor at the Yerkes Observatory of the University of Chicago and then returned to the Lowell Observatory, where he was able to devote himself entirely to the further development of photoelectric methods of photometry without teaching obligations and under favorable climatic conditions .
In 1953 he introduced the UBV system for measuring brightness in three different wavelength ranges around 0.365 μm, 0.44 μm and 0.55 μm, which became the standard. Color-brightness diagrams in the UBV system have become an important tool for studying the properties of stars and the effects of interstellar extinction .
During his time as a professor at the University of Texas from 1959 to 1962 and then at the University of Arizona , he expanded his photometric system into the infrared and dealt with the spectroscopy of stars in infrared light. In the 1960s he made connections with astronomical institutes in Mexico and in 1979 moved to the Universidad Nacional Autónoma de México in Mexico City. Johnson died of a heart attack in 1980.
Awards
- 1956 Helen B. Warner Prize
- 1969 member of the National Academy of Sciences
Web links
- HL Johnson publications in the Astrophysics Data System
- Obituaries for HL Johnson in the Astrophysics Data System
| personal data | |
|---|---|
| SURNAME | Johnson, Harold Lester |
| BRIEF DESCRIPTION | American astronomer |
| DATE OF BIRTH | April 17, 1921 |
| PLACE OF BIRTH | Denver , Colorado, USA |
| DATE OF DEATH | April 2, 1980 |
| Place of death | Mexico city |