Seeing the Universe
before 1610 - naked eye astronomy 1608 - Galileo's hand held telescopes 1673 - Hevelius' long telescopes1780 - Herschel's large reflectors
1838 - Meridian Circles 1845 - Rosse's Leviathian 1890 - Barnard's camera 1923 - The Hooker 100 inch 1948 - The Palomar 200 inch 1990 - The Hubble Space Telescope 1998 - The Keck 10 metre pair 2000 - The VLT array 2015 - Planning for the JWST 2020? - Planning the OWL How much further?
In 1781 William Herschel discovered the planet Uranus. He also discoverd
moons around Saturn and Uranus, realised that spectrum of star light extended
beyond the visble into the infrared, mapped thousands of nebulae, and deduced
the structure of the Milky Way. In his quest for better views of the universe,
he built a series of reflecting telescopes. The image shows the largest,
with a 48 inch mirror, constructed in 1786. It prooved difficult to use.
The observer, standing on the platform, peering into the body of the instrument,
steered it onto targets by calling out instructions to a team of workmen. They
pushed the structure around its track and hauled on ropes, running through a pulley
system, to raise or lower the tube. Herschel returned to doing most of his work on
an earlier, more manageable, 24 inch reflector.
The Herschel Museum
Herschel's 48 inch reflecting telescope (Herschel Museum)