Dorpat Refracting Telescope
Joseph von Fraunhofer
Joseph von Fraunhofer (1787-1826) is often called the “Father of Astrophysics” for his discovery of the famous Fraunhofer Absorption Lines in the solar spectrum, and his attribution of these tiny black lines to the Sun itself. He was the finest optician and lens maker of his time, creating many important instruments including telescopes and heliometers, and developed the diffraction grating used even today to measure the wavelengths of light. He died at a tragically early age of 39.
His last instrument was also his finest. The Dorpat Refractor is named for the observatory in Tartu, Estonia, where it was first installed, and is on display today. At 9.5” f15, it was the largest telescope in the world in 1826, and was the first application of his major inventions of the Clock Drive and Equatorial Mount. The Dorpat has long been my favorite scientific instrument for its beauty and importance in the History of Science.
I researched and built a physical 1/12th Scale model in 1987 for the National Geographic Society’s Centennial Exhibition, and my SolidWorks™ CAD model, rendered in hyperShot™ was created from my personal research collection acquired from many libraries and historians, including the director of the Museum.
The Dorpat has recently been painstakingly restored to operating condition, and is now on display in its home at the Tartu Observatory.