The Antique Telescope Society
Historical documents, galleries and information on maintaining and restoring old telescopes.
http://www1.tecs.com/oldscope/

The Astrolabe
Ancient astronomical computer.
http://astrolabes.org/astrolab.htm

Caltech Astronomy - History
The telescopes at Mt. Wilson and Palomar.
http://www.astro.caltech.edu/observatories/palomar/history/

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The exquisite telescopes crafted by Alvan Clark and his sons helped make the last half of the 19th century a golden age of astronomy.
http://www.smithsonianmag.si.edu/smithsonian/issues01/oct01/refractors.html

Churches as Scientific Instruments
Solar observatories built into 17th and 18th century cathedrals.
http://cis.alma.unibo.it/NewsLetter/090496Nw/Heilbron.htm

Sir Martin Ryle - Nobel Lecture
Radio telescopes of large resolving power.
http://www.nobel.se/physics/laureates/1974/ryle-lecture.html

36 Years Ago
An essay with photographs on the construction of the Arecibo radio telescope.
http://www.naic.edu/about/history/35years.htm

Important Astronomers, their Instruments and Discoveries
From the merket to the reflecting telescope in three pages.
http://seds.lpl.arizona.edu/billa/psc/hist1.html

Virtual Museum of Measuring Engines
The history of modern astronomical measurement, emphasis on instruments.
http://www.astro.virginia.edu/~afs5z/engines.html

The Airy Transit Circle
Describes the modernization of the Greenwich Observatory. From the BBC History series.
http://www.bbc.co.uk/history/discovery/revolutions/airy_george_01.shtml

The 28-inch Photo-visual Refractor
Exhibition from the Royal Observatory, Greenwich, that explains the history of this telescope via words and archive photographs.
http://www.nmm.ac.uk/server.php?request=setTemplate:singlecontent&contentTypeA=conWebDoc&contentId=354&navId=005001004

Antique Telescopes
An overview with photographs of many lesser known telescopes typical of their time.
http://www.antiquetelescopes.org/