Description:
- Object ID: ALSA 2006.24.01
- Made by: AGA Geodimeter
- Model: 6
- Serial Number: 6571
- Date Made: circa 1964.
- Approximate size: 21″ high, 14″ wide, 8.5″ deep
- Accessories: The instrument comes with a tan colored fiberglass back back mounted instrument case . The case contains: one 12 volt battery cable, one monogram and calibration table.
- Condition: good
Commentary:
Serial 6571. This instrument is 21″ high, 14″ wide, 8.5″ deep (with scope in vertical position). A large electronic beam generator in an aiming tube. It is mounted on a tripod at point A. It is powered by a 12 volt battery to generate the beam which is reflected by a glass prism at a point B.
The geodimeter Model 6 introduced in 1964, was a transisorized instrument with coaxilly mounted transmitter and recieving optics. It had a range of 1-2 miles in daylight and 10 miles in darkness. It had a standard accuracy of 5mm +1mm/km. Without a case or tripod it weighed a mere 35 pounds.
Equipped with a tungsten lamp and various accessories, it cost approximately $10,000 and could be powered with a 12 volt car battery. A mercury vapor lamp for the model 6 cost some $2,500 more and required a special generator.
The Geodimeter (acronym for geodetic distance meter) was the invention of the Swedish Physicist Dr. Erik Bergstrand who designed and applied it to the measurement of the speed of light over measured distances in 1947. His original device, introduced in 1949, weighed more than 100 kilograms and was the first EDM instrument ever made..
Source of Object: Donated by J.B. Underwood & Associates Ltd.
Notes:
References:
- Visit article Measuring by Speed of Light – The Geodimeter for additional information.
- R. Smith “The History of Geodimeter, 1947-1997, http://www.geotronics.it/public/geodimeter_story.pdf
- James Smith Murphy, Electronics Based Innovation in a Niche Market: Distances Measured By The Speed Of Light, Thesis submitted to the Graduate Faculty of North Carolina State University. 2004: https://repository.lib.ncsu.edu/bitstream/handle/1840.16/961/etd.pdf?sequence=1
- 100 Years of Geodetic Surveys in Canada. https://www.nrcan.gc.ca/maps-tools-publications/maps/100-years-geodetic-surveys-canada/9110
- Spectra Geospatial, About Us: https://spectrageospatial.com/about-us/
Description by: Updated by Ed Titanich, October 3, 2024.