A telescope is a tool that astronomers use to determine faraway objects. Most telescopes, and mostly all large telescopes, work by using curved mirrors to assemble and focus light from the night sky. The primary telescopes focus light by using pieces of curved, clear glass, called lenses.
There are two basic types of telescopes, refractors and reflectors. The part of the telescope that gathers the sunshine, called the objective. A refractor telescope uses a glass lens as its objective.
The history of the telescope are often traced on before the invention of the earliest known telescope, which appeared in 1608 within the Netherlands, when a patent was submitted by Hans Lippershey, an eyeglass maker. Although Lippershey failed to receive his patent, news for the invention soon spread across Europe. The planning of those early refracting telescopes consisted of a convex objective lens and a concave eyepiece. Galileo improved on this design the subsequent year and applied it to astronomy. In 1611, Johannes Kepler described how a way more useful telescope can be made with a convex objective lens and a convex eyepiece lens. By 1655, astronomers like physicist were building powerful but unwieldy Keplerian telescopes with compound eyepieces
During the period 1850–1900, reflectors suffered from problems with speculum metal mirrors, and a substantial number of “Great Refractors” were built from 60 cm to 1 metre aperture, culminating within the Yerkes Observatory refractor in 1897; however, ranging from the first 1900s a series of ever-larger reflectors with glass mirrors were built, including the Wilson 60-inch (1.5 metre), the 100-inch (2.5 metre) Hooker Telescope (1917) and therefore the 200-inch (5 metre) Hale telescope (1948); essentially all major research telescopes since 1900 are reflectors. variety of 4-metre class (160 inch) telescopes were built on superior higher altitude sites including Hawaii and also the Chilean desert within the 1975–1985 era. the event of the computer-controlled alt-azimuth mount within the 1970s and active optics within the 1980s enabled a brand-new generation of even larger telescopes, starting with the 10-metre (400 inch) Keck telescopes in 1993/1996, and variety of 8-metre telescopes including the ESO Very Large Telescope, Gemini Observatory and Subaru Telescope.
The era of radio telescopes (along with radio astronomy) was born with Karl Guthe Jansky’s serendipitous discovery of an astronomical radiator in 1931. Many varieties of telescopes were developed within the 20th century for a large range of wavelengths from radio to gamma-rays. The event of space observatories after 1960 allowed access to many bands impossible to watch from the bottom, including X-rays and longer wavelength infrared bands.
CLAIMS OF PRIOR INVENTION
In 1655 Dutch diplomat William de Boreel tried to resolve the mystery of who invented the telescope. He had a known magistrate in Middelburg to follow up on Boreel’s childhood and early adult recollections of a spectacle maker named “Hans” who he remembered because the inventor of the telescope. The magistrate was contacted by a then unknown claimant, Middelburg spectacle maker Johannes Zachariassen, who testified that his father, Zacharias Janssen invented the telescope and also the microscope as early as 1590. This testimony seemed convincing to Boreel, who now recollected that Zacharias and his father, Hans Martens, who he remembered.
SPREAD THROUGH EUROPE
The Italian polymath astronomer was in Venice in June 1609 and there heard of the “Dutch perspective glass”, a military spyglass, by means of which distant objects appeared nearer and bigger. Galileo states that he solved the matter of the development of a telescope the primary night after his return to Padua from Venice and made his first telescope the following day by fitting a lens in one extremity of a leaden tube and a diverging lens within the other one. some days afterwards, having succeeded in making a far better telescope than the primary, he took it to Venice where he communicated the small print of his invention to the general public and presented the instrument itself to the doge Leonardo Donato, who was sitting fully council. The senate reciprocally settled him forever in his lectureship at Padua and doubled his salary.
Galileo spent his time to improving the telescope, producing telescopes of increased power. His first telescope had a 3x magnification, but he soon made instruments which magnified 8x and at last, one nearly a meter long with a 37mm objective (which he would stop all the way down to 16mm or 12mm) and a 23x magnification. With this last instrument he began a series of astronomical observations. In October or November 1609, discovering the satellites of Jupiter, hills and valleys on the Moon, the phases of Venus and observed spots on the sun (using the projection method instead of direct observation). Galileo noted that the revolution of the satellites of Jupiter, the phases of Venus, rotation of the Sun and therefore the tilted path its spots followed for a part of the year pointed to the validity of the sun-centered framework over other Earth-centered systems like the one proposed by Ptolemy. Galileo’s instrument was the primary to tend the name “telescope”. The name was invented by the Greek poet/theologian Giovanni Demisiani at a banquet perseved day.
