Telescopes
Man has always looked to the heavens for answers. Ancient creation myths always connected Gods and Goddesses with the heavens, as if they knew there was a deeper connection.
A telescope is an instrument designed for the observation of remote objects by the collection of electromagnetic radiation. The first known practically functioning telescopes were invented in the Netherlands at the beginning of the 17th century. "Telescopes" can refer to a whole range of instruments operating in most regions of the electromagnetic spectrum. The word "telescope" (from the Greek tele = 'far' and skopein = 'to look or see'; teleskopos = 'far-seeing') was coined in 1611 by the Greek mathematician Giovanni Demisiani for one of Galileo Galilei's instruments presented at a banquet at the Accademia dei Lincei. In the Starry Messenger Galileo had used the term "perspicillum".
History of Telescopes
The earliest known working telescopes appeared in 1608 and are credited to Hans Lippershey. Among many others who claimed to have made the discovery were Zacharias Janssen, spectacle-makers in Middelburg, and Jacob Metius of Alkmaar. The design of these early refracting telescopes consisted of a convex objective lens and a concave eyepiece. Galileo used this design the following year.
In 1611, Johannes Kepler described how a telescope could be made with a convex objective and eyepiece lens and by 1655 astronomers such as Christiaan Huygens were building powerful but extremely large and unwieldy Keplerian telescopes with compound eyepieces. Hans Lippershey is the earliest person documented to have applied for a patent for the device.
Isaac Newton is credited with building the first "practical" reflector in 1668 with a design that incorporated a small flat diagonal mirror to reflect the light to an eyepiece mounted on the side of the telescope. Laurent Cassegrain in 1672 described the design of a reflector with a small convex secondary mirror to reflect light through a central hole in the main mirror.
The achromatic lens, which greatly reduced color aberrations in objective lenses and allowed for shorter and more functional telescopes, first appeared in a 1733 telescope made by Chester Moore Hall, who did not publicize it. John Dollond independently developed achromatic lenses and produced telescopes using them in commercial quantities starting in 1758.
Important developments in reflecting telescopes were John Hadley's production of larger paraboloidal mirrors in 1721; the process of silvering glass mirrors introduced by Léon Foucault in 1857; and the adoption of long lasting aluminized coatings on reflector mirrors in 1932. Almost all of the large optical research telescopes used today are reflectors.
The first radio telescope was built by Grote Reber in 1937, and many types of telescopes were developed in the 20th century for a wide range of wavelengths from radio, to gamma-rays.
Optical Telescope Wikipedia
Radio Telescope Wikipedia
Solar Telescope Wikipedia
Telescope Wikipedia
Notable Telescopes Wikipedia
Telescopes Under Development Wikipedia
ALPHABETICAL INDEX OF ALL FILES
