Historic Scientific Instruments
at Ladd Observatory

Ladd Observatory

About the Observatory

Brown University's historic Ladd Observatory was constructed in 1890-91 and opened in October 1891 under the direction of Prof. Winslow Upton. A regular program of transit observations and time keeping was started in 1893. Prof. Charles Smiley, famous for his observations of solar eclipses, became director of Ladd Observatory in 1938. Dean David Targan is the current director.

The Observatory is open to the public for telescope viewing on Tuesday evenings, weather permitting. For more information, including the schedule and directions, see the Ladd Observatory homepage.


The Instrument Collection

The Ladd Observatory houses a 12" refracting telescope with a lens made by John A. Brashear of Pittsburgh following the lens design of Prof. Charles S. Hastings of Yale University. The equatorial mounting and mechanical clock drive were made by George N. Saegmüller of Washington D.C. The telescope is equipped with a filar micrometer, spectroscope, and other attachments.

There are also transit telescopes, precision pendulum clocks, chronometers, and various minor instruments. The links below are to images of the instrument makers' marks and indicates that the timepiece is located in the main clock vault. This is only a partial list of the many historic instruments in the Ladd Observatory collection.

Astronomical Clocks & Regulators

Image courtesy of Carl R. Friend

Frodsham chronometer

Chronograph

  • Warner & Swasey    Cleveland, Ohio    (1890)

Chronometers

Transit Instruments

  • 2 ¼"    (maker unknown)
  • 2 ½"    (maker unknown)
  • 50mm Parkinson & Frodsham    Liverpool
    (ca. 1838) Status: restoration in progress.
  • 80mm Saegmüller    Washington D.C.
    (1890; can also be used as a zenith telescope)

Observatory library

Research & Restoration

A research project on the historic scientific instruments at the Ladd Observatory began in September 2004. The goals are to restore and preserve these instruments, and to research the history of how they were used during the early years of the Observatory. The progress of this project will be documented on this web site.

The first major restoration is the Clemens Riefler astronomical clock. Philip Hannah, Certified Master Watchmaker, commenced work on October 21st to return the clock to good working order. Information about this historic clock and the status of the restoration is available at the Clemens Riefler astronomical clock web page. Concurrently, Mr. Hannah is also restoring the Charles Frodsham chronometer.

The Howard regulator has been in operation for a few months now and is performing well. At the end of Daylight Savings the clock was reset from the local timezone to Greenwich Mean Time. Procedures to calibrate the rate of the clock have commenced, with the first adjustment on Jan. 25th, 2005.

The Parkinson & Frodsham transit instrument is in very good condition. The optics have recently been cleaned and the telescope was used to observe the lunar eclipse of Oct. 27, 2004. Some minor work remains to be done. It was originally "used by James Munroe in New Bedford in 1838 in the rating and adjusting of chronometers for the whaling fleet." (Prof. Charles Smiley, in a letter to Charles P. Barber of the Providence Journal dated July 3, 1940.)


Telescope viewing

Education & Outreach

Some of the scientific instruments are on display and may be seen on Tuesday evenings when the Observatory is open to the public for telescope viewing. For the schedule and directions see the Ladd Observatory homepage.

Site Index

Valid HTML 4.01! Copyright © 2005 by Michael L. Umbricht
Last modified: 20:35 Feb. 09, 2008

http://physics.brown.edu/physics/commonpages/ladd/history/main.shtml