The Yerkes 40 inch refractor telescope - 1897
![](https://cdn.sci.esa.int/documents/33580/35361/1567216454555-Yerkes_40_inch_Refractor_Telescope-1897_625.jpg)
Date: 01 December 2013
The 40-inch (102 cm) refractor telescope at Yerkes Observatory, Wisconsin, USA, was used by Frank Schlesinger for parallax measurements.
Last Update: 23 September 2021
The 40-inch (102 cm) refractor telescope at Yerkes Observatory, Wisconsin, USA, was used by Frank Schlesinger for parallax measurements.