Telescopes


Hubble Space Telescope


April 24, 1990 - Hubble Turns 30



Hubble telescope delivers stunning 30th birthday picture
  BBC - April 24, 2020

The best Hubble Space Telescope images of all time
  BBC - April 24, 2020

NASA's Hubble telescope - here's a look at Lockheed Martin building it
  CNBC - April 24, 2020




The Arecibo Observatory



The Arecibo Observatory


The telescope was damaged by Hurricane Maria in 2017 and was affected by earthquakes in 2019 and 2020. Two cable breaks, one in August 2020 and a second in November 2020, threatened the structural integrity of the support structure for the suspended platform and damaged the dish. Due to uncertainty over the remaining strength of the other cables supporting the suspended structure, and the risk of collapse due to further failures making repairs dangerous, the NSF announced on November 19, 2020, that it would decommission and dismantle the telescope, with the radio telescope and LIDAR facility remaining operational.


Arecibo radio telescope, damaged beyond repair, seen from space


Scientists Are Sharing Memories of The Iconic Arecibo Telescope, And It's Emotional




Arecibo Message


The Arecibo message is an interstellar radio message carrying basic information about humanity and Earth that was sent to globular star cluster M13 in 1974. It was meant as a demonstration of human technological achievement, rather than a real attempt to enter into a conversation with extraterrestrials.

The message was broadcast into space a single time via frequency modulated radio waves at a ceremony to mark the remodeling of the Arecibo radio telescope in Puerto Rico on 16 November 1974. The message was aimed at the current location of M13, about 25,000 light years from Earth, because M13 was a large and relatively close collection of stars that was available in the sky at the time and place of the ceremony. When correctly translated into graphics, characters, and spaces, the 1,679 bits of data contained within the message form the image shown here.




Search for Extraterrestrial Intelligence ~ SETI


Man has always looked to the skies for answers ... as if a celestial blueprint that tells the story of humanity's journey in time and space. Creation myths connect gods with the heavens, often the constellations, sometimes with a link to ancient aliens who came to Earth to seed humanity and will one day return. As the millennia progressed, so too did the use of telescopes to find answers to many of these age-old questions. That quest continues today with new and more advanced technologies as we venture into space. One has to wonder ... have any of the advanced telescopes ever captured the image of a UFO.





A telescope is an instrument that aids in the observation of remote objects by collecting electromagnetic radiation (such as visible light). The first known practical telescopes were invented in the Netherlands at the beginning of the 17th century, using glass lenses. They found use in terrestrial applications and astronomy.

Within a few decades, the reflecting telescope was invented, which used mirrors. In the 20th century many new types of telescopes were invented, including radio telescopes in the 1930s and infrared telescopes in the 1960s. The word telescope now refers to a wide range of instruments detecting different regions of the electromagnetic spectrum, and in some cases other types of detectors.

The word "telescope" 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". Read more




History of Telescopes

The earliest recorded working telescopes were the refracting telescopes that appeared in the Netherlands in 1608. Their development is credited to three individuals: Hans Lippershey and Zacharias Janssen, who were spectacle makers in Middelburg, and Jacob Metius of Alkmaar. Galileo heard about the Dutch telescope in June 1609, built his own within a month, and greatly improved upon the design in the following year.


Galileo's telescope reaches 400th anniversary - August 25, 2009



The idea that the objective, or light-gathering element, could be a mirror instead of a lens was being investigated soon after the invention of the refracting telescope. The potential advantages of using parabolic mirrors - reduction of spherical aberration and no chromatic aberration - led to many proposed designs and several attempts to build reflecting telescopes. In 1668, Isaac Newton built the first practical reflecting telescope, of a design which now bears his name, the Newtonian reflector.

The invention of the achromatic lens in 1733 partially corrected color aberrations present in the simple lens and enabled the construction of shorter, more functional refracting telescopes. Reflecting telescopes, though not limited by the color problems seen in refractors, were hampered by the use of fast tarnishing speculum metal mirrors employed during the 18th and early 19th century a problem alleviated by the introduction of silver coated glass mirrors in 1857, and aluminized mirrors in 1932. The maximum physical size limit for refracting telescopes is about 1 meter (40 inches), dictating that the vast majority of large optical researching telescopes built since the turn of the 20th century have been reflectors. The largest reflecting telescopes currently have objectives larger than 10 m (33 feet).

The 20th century also saw the development of telescopes that worked in a wide range of wavelengths from radio to gamma-rays. The first purpose built radio telescope went into operation in 1937. Since then, a tremendous variety of complex astronomical instruments have been developed. Telescopes





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