Master clocks
Title
Master clocks
Subject
Astronomy
Clocks
Measuring instrument
Clocks
Measuring instrument
Description
Wood, glass, metal
They are model 25 IBM Master clocks. There are two 60 beat with a Graham dead-beat escapement with micrometer adjustment. Magnet wound, spring drive, self-regulating movement, 63 1/6” x 19 ¼” x 7 5/8”, plain glass door, 12” Arabic dial, white with black numbers, separate hours and smaller seconds circle. There is a one second switch as well as a 59 second switch. Pendulum is a mercurial compensating pendulum, 45 5/16 inches long and approximately 11.5 pounds, accurate to 10 seconds over a 30-day period. The standard time clock has the original mercurial pendulum with two cylinders. The sidereal clock pendulum is a replacement Invar pendulum with one cylinder. Clocks are automatically wound with reserve power for approximately 12 hours. Clocks are housed in a walnut wood case with a glass door and two locks.
A=central standard time (south side of pier), B=local sidereal time (east side of pier). Clock serial numbers are 462905 and 462904.
Included in the purchase order was the new switching wiring and metal storage cabinet and control panel outside the clock room. Paper instructions included.
These clocks replaced the original 1896 Clemens Riefler clocks both of which are now part of the Alder Planetarium collect.
They are model 25 IBM Master clocks. There are two 60 beat with a Graham dead-beat escapement with micrometer adjustment. Magnet wound, spring drive, self-regulating movement, 63 1/6” x 19 ¼” x 7 5/8”, plain glass door, 12” Arabic dial, white with black numbers, separate hours and smaller seconds circle. There is a one second switch as well as a 59 second switch. Pendulum is a mercurial compensating pendulum, 45 5/16 inches long and approximately 11.5 pounds, accurate to 10 seconds over a 30-day period. The standard time clock has the original mercurial pendulum with two cylinders. The sidereal clock pendulum is a replacement Invar pendulum with one cylinder. Clocks are automatically wound with reserve power for approximately 12 hours. Clocks are housed in a walnut wood case with a glass door and two locks.
A=central standard time (south side of pier), B=local sidereal time (east side of pier). Clock serial numbers are 462905 and 462904.
Included in the purchase order was the new switching wiring and metal storage cabinet and control panel outside the clock room. Paper instructions included.
These clocks replaced the original 1896 Clemens Riefler clocks both of which are now part of the Alder Planetarium collect.
Creator
IBM
Publisher
Astronomy Department, University of Illinois, Urbana, Illinois
Date
1954
Contributor
Michael Svec
Rights
Copyright Michael Svec
Format
image/jpg
Language
English
Type
physical object
Identifier
University of Illinois Observatory Collection A211.1, 211.2
University ID 196631A, 196631B
University ID 196631A, 196631B
Coverage
University of Illinois Observatory, Urbana, Illinois
Files
Collection
Citation
IBM, “Master clocks,” University of Illinois Observatory Collection, accessed April 18, 2024, https://uiobservatory.omeka.net/items/show/19.