The McCormick Observatory News

Fall 1995


Still going strong in its 110th year, the McCormick `Great Refractor' is to the best of our knowledge the only telescope of its size and age still used regularly in research, teaching, and public viewing programs. It was the largest telescope in the United States at the time of its inauguration in 1885, and it is still the fourth largest telescope of its kind in the U.S.

The research emphasis is "astrometry". Photographs obtained on glass plate negatives with the McCormick telescope constitute our basic observational data. The main point of this work is to determine fundamental physical parameters for nearby stars, such as luminosity and mass, through high precision measurements of stellar distance ("trigonometric parallax") and the orbits of double stars. The photographic program was begun in 1914, and the McCormick Observatory is internationally renowned as one of the world's four most productive astrometric observatories.

Observatory Highlights

The regular first and third Friday night public program has continued to be very popular and well received by local Charlottesville residents and area visitors alike. Most recently people have been treated to views of Saturn with its ring system edge on. About 75 people a night come to McCormick, and we have had about 300 people at Fan for each of its twice yearly open nights. Daytime tours were also given to school children during the week and for several special Saturday school enrichment programs.

The next Fan Mountain open night will be held on April 19, 1996. For further information contact the Astronomy Department (804-924-7494). Public night schedules and information is also available on the World Wide Web from the Department home page:

A major crisis developed in early February when we learned that author John Grisham was going to fund a Little League baseball park at the foot of Fan Mountain, within two miles of our telescopes. Called Cove Creek Park, there were to be four playing fields and two practice fields with sports lighting for all four playing fields. Fan Mountain is the largest dark sky research observatory on the east coast. The field lighting would have destroyed that dark sky, brightening the sky in the direction of the park to the level of the full moon. Through an intense effort by the Astronomy Department, the University, and friends of the Observatory, we were able to convey to Mr.Grisham the detrimental effect the lights would have on the Observatory, and he decided to drop plans for lighting the fields. The 40--inch is now twenty years old, and an evaluation last year showed some serious wear problems in the tracking system. State funds have become available to fix the right ascension tracking, and this work will be done by DFM Engineering of Longmont, Colorado. The modifications will include a large bearing at the south end of the polar axis and a new friction drive design to smooth out the telescope motions. The bearing will take most of the downward thrust load of the telescope. New drive motors and position encoders will be installed, as will be a new computer control system.

Research Highlights