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G. W. Lockwood (Lowell Observatory), M. Jerzykiewicz (Astronomical Institute, Wroclaw University)
The return of Harold L. Johnson to Lowell Observatory in 1952 marked the beginning of a half century of precise photoelectric photometry using a new 21-inch reflecting telescope that remains in service today. A 1953 newspaper headline proclaimed "Lowell's New Telescope to Train on Sun's Light," a somewhat misleading description that nevertheless captures the spirit of work carried out over the past half century. Johnson completed observations defining the UBV system and began regular measurements of Uranus and Neptune in a long-running effort to characterize solar variability by monitoring reflected planetary light. Although spacecraft measurements after 1980 show that the Sun's variation is less than 0.1% and thus undetectable from the ground, the "Solar Variability" theme motivated long-term studies of the variations of sunlike stars and solar system objects. Perhaps the telescope's most enduring contribution has been to supply data characterizing the sub-1% variability of sunlike stars and the power law relationship between photometric variability and mean chromospheric activity.
We illustrate the output of this highly productive facility with a sampling of results from the past half century, including 50-year lightcurves of Uranus and Neptune, a 29.5 year complete seasonal lightcurve of Titan, lightcurves of sunlike stars (now being extended into a third decade by automated telescopes at Fairborn Observatory), and shorter term projects on hot main sequence pulsators. It is unlikely that these projects would have been deemed feasible without guaranteed, uninterrupted, and convenient access to a dedicated telescope.
Work described here has been supported almost without interruption by the NSF Solar-Terrestrial program, NASA Planetary Astronomy, and the United States Air Force.
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Bulletin of the American Astronomical Society, 37 #4
© 2005. The American Astronomical Soceity.