Yerkes observatory telescope
Created: 1897
Creator: University of Chicago and Alvin Clark Location: Williams Bay, Wisconsin Stats: Lens: 1m (diameter) Light Collecting Area: 0.79m squared Light Gathering Power: 40,000x human eye Focal Length: 19.9m Focal Ratio: f/20 Wavelength: Optical Type: Refractor |
History:
Like the James Lick Telescope, the funding for this huge refractor in Wisconsin came from a businessman who wanted his legacy to be the largest telescope in the world. Chicago tycoon Charles Tyson Yerkes commissioned Alvin Clark to lead the construction of the telescope at Lake Geneva in Wisconsin. Unlike that of most large telescopes being built at the time, this location was relatively low. However, the location lent itself well to observations because the sky was generally clear and there were hardly ever any storms. At the time it was completed, the Yerkes telescope was the largest of its kind in the world. It is over 18m long and weighs in at 20 tons. Both the telescope and the viewing platform were designed to be controlled by motors, allowing for greater calibration to optimize the observational experience. Due to its huge size, the Yerkes telescope essentially reached the limit of feasibility for building bigger and bigger refractors. Designing a larger lens would not improve the light collection capabilities and would actually present structural problems due to its weight. As such, the Yerkes telescope represents the end of the era of great refractors. Amongst the most important discoveries at Yerkes was that interstellar dust concealed a large proportion of the starlight in the Milky Way. The refractor was also used to measure the orbits of stars around each other, which helped our ability to accurately measure stellar masses. Finally, the Yerkes telescope was used to make major contributions in the field of stellar spectroscopy, allowing Otto Struve to determine the chemical makeup of numerous stars in our galaxy. |