Eye of the beholder: a look through microscopes and telescopes

The lens telescope
The starlit sky has fascinated humanity since ancient times but it was not until the beginning of the 17th century that researchers began to develop the first telescopes. Around 1610 a dispute broke out between Galileo Galilei and Ansbach court astronomer Simon Marius over the discovery of the moons of Jupiter. However, one thing became clear: as a result of the findings of the new lens telescopes, mankind had to bid farewell to the geocentric world view—the misguided belief that the earth was the center of the universe.

The Fraunhofer refractor
During the Age of Enlightenment in the 18th century, there was a growing interest in astronomy. In 1781 Friedrich Wilhelm Herschel discovered the planet Uranus, just before Munich optician and physicist Joseph von Fraunhofer began constructing telescopes in a scientific fashion at the start of the 19th century.

This refractor was created in 1828 at Joseph von Fraunhofer's Optical Institute, 2 years after his death. In 1829 the telescope was installed in the Royal Observatory in Berlin, and was used by astronomer Johann Gottfried Galle in his discovery of the planet Neptune in 1846.

Joseph von Fraunhofer
Born in 1787, the 11th son of a glazier from Straubing, Lower Bavaria, Fraunhofer joined Georg Friedrich von Reichenbach's Mathematical-Mechanical Institute as an optician when he was just 19. He developed the spectroscope in 1814 and discovered and gave his name to the Fraunhofer lines in the sun's spectrum in 1817. In 1824 he became an honorary citizen of the city of Munich and was knighted. Fraunhofer died of pulmonary tuberculosis in 1826 at the age of just 39. This oil painting by Rudolf Wimmer from 1905 hangs in the Hall of Fame in the Deutsches Museum. It shows Fraunhofer holding a prism, standing next to his spectroscope.

Carl Zeiss
A certain Carl Zeiss was only 7 years old when Fraunhofer died. Shortly after his 30th birthday, Zeiss set up a workshop for optics and precision mechanics. In close collaboration with his colleagues, physicist Ernst Abbe (1840–1905) and chemist and glass specialist Otto Schott (1851–1935), Zeiss developed the best and most precise microscopes in the world. The company, which was named after him and is still based in Jena, is now a global corporation with multiple sites worldwide.

The telescope in the Western Observatory
Zeiss also produced the refractor that was specially designed for the Deutsches Museum in 1924 and has stood in the Western Observatory on the Museum Island since 1925. It was used for astronomical observations until 2008, when the mechanics were damaged. While the gigantic 8.4-ton telescope was transported to Jena and overhauled in 2010, renovations began in the western dome. In 2012 the telescope was returned to Munich.

The telescope in the Eastern Observatory
This telescope, constructed by the Goerz corporation in Berlin in 1913, was originally designed for an expedition by the Technical University of Berlin and Goerz
to observe the total solar eclipse of August 21, 1914
in Norway. This expedition was canceled due to the outbreak of the First World War. Since the opening of the museum building in 1925, the Goerz telescope has been the main instrument in the Eastern Observatory of the Deutsches Museum. It was restored in Jena in 2009. The eastern dome was renovated in 2011.

It is still fully functional today and provides spectacular insights into the vastness of space. Whether here in the constellations of Taurus and Orion…

…the planets of our solar system such as Jupiter…

...Saturn...

…the sun itself at a distance of over 90 million miles…

…or even the Oktoberfest Ferris wheel from 1.2 miles away.

The ESO telescope in Chile
The European Southern Observatory (ESO) in the Atacama Desert in Chile is home to the most modern telescopes in the world today. ESO's best-known telescope currently is probably the Very Large Telescope (VLT) at the Paranal Observatory, which was able to analyze carbon monoxide molecules in a galaxy about 11 billion light years away for the first time ever. Starting in 2020, the ESO wants to use the Extremely Large Telescope (ELT), which has a mirror diameter of almost 40 meters, to investigate the earliest objects of our solar system and planets outside our solar system.

The planetarium
On May 7, 1925 a premiere was held in the Deutsches Museum for the world's first projection planetarium, where visitors could gaze at a simulated starlit sky projected onto the dome above them. At the heart of the planetarium is the star projector: a complex optical device with precise mechanics that imitates the starlit sky. The first planetarium projector in the world was developed and built at Zeiss from March 1919 to July 1923.

The planetarium still enjoys incredible popularity today. Here visitors can see not just the night sky over Munich, but also the sky over any point on earth. This is made possible through the state-of-the-art Zeiss-Skymaster ZKP4 fiber-optic star projector, which creates displays of starlit skies and planetary movements using LED light sources and around 7,300 optical fibers. Visitors can travel 13.7 billion light years to the limits of the observable universe, flying to planets and looking at our solar system or the Milky Way from the outside as they go.

Microscope by Antoni Van Leeuwenhoek
Antoni Van Leeuwenhoek (1632–1723) from Holland was passionate about microscopes. Because the microscopes at that time were not particularly good, he built them himself, constructing around 500 microscopes over his lifetime. Their core part was a single lens but one that was perfectly polished and free from blemishes. This allowed him to reach magnifications of up to 270x.

Thanks to his microscopes, Antoni van Leeuwenhoek is still considered a pioneer of microbiology, having provided the first accurate description of red blood cells in 1674, shown how blood cells circulate through the ears of a rabbit and proved that fleas and corn weevils, for example, developed from eggs and did not spontaneously emerge from sand, as was believed at the time.

Leeuwenhoek was so proud of his microscopes that he never sold them, not even to royalty such as Peter the Great or Frederick the Great of Prussia.

Many people wanted to know how he managed to make such perfect lenses. It is believed that he achieved this lens quality mostly through melting, and less through grinding. But he never revealed his secret. So, once he passed away, bacteria could not be observed again until the 19th century, when people learned to construct even higher-quality microscopes.

The Waterhouse microscope
Special microscopes for museums and exhibitions were created at the start of the 20th century so that even the tiniest of objects could be viewed by a large audience. Here we can see the 1931 Waterhouse microscope.

Through this microscope, observers gained deep insights into the secrets of nature and saw plants and creatures as they'd never seen them before, from the common flea to the bristles of a stinging nettle or ...

...the sucker of a blow fly!

The electron microscope
The development of the electron microscope, which uses electron beams instead of visible light to create an image of an object, was a breakthrough. Electrical engineer Ernst Ruska (1906–88) took advantage of the fact that electron beams have a much shorter wavelength compared to light, and therefore a much higher resolution. The electron beam is sent through a vacuum, as it would otherwise be deflected by air molecules. Electron microscopes can now be used to reach a resolution in the nanometer range. In 1986 Ernst Ruska received the Nobel Prize in Physics for his invention.

Through the scanning electron microscope, observers gain unprecedented insights into the microcosm of nature—like in the Microscopic Theater presentations in the Deutsches Museum—with fascinating 3D effects. Like here, with an ant…

…a pill bug…

…or a head louse.