Who invented the astronomical telescope (the origin of the astronomical telescope)
The origin of the astronomical telescope
The picture shows the Spanish Canary Telescope.
Records of the telescope first appeared in a patent report submitted to the *** by a Dutch spectacle maker in 1608.
In 1999, when the astronomer Galileo heard the news of the new invention of the telescope, he immediately applied the telescope to astronomical observations.
When Galileo aimed at the starry sky through the telescope, he saw an unprecedented scene: there are craters on the moon, and there are 4 satellites around Jupiter…
Since then, astronomical observation Entering a new stage, astronomers no longer rely solely on the naked eye to gain insight into the mysteries of the universe.
The diameter of the pupil is only 6mm, and the light that can enter the eye through the pupil is limited. The aperture of the telescope is larger than the human pupil, which can collect light from a larger area, allowing astronomers to see fainter objects and richer details on them.
The performance of an astronomical telescope depends on many indicators, and the observation effect is also closely related to the observation environment. But the aperture of the telescope is always an important indicator. This is also an indicator that people have been working on improving during the development of astronomical telescopes. Galileo used an astronomical telescope with a diameter of only 4.2 centimeters. The single optical telescope with a larger aperture that has been put into use at present is the Spanish gran telescopio canarias, with an aperture of 10.4 meters.
The telescope used by Galileo is similar to our common telescope: the light passes through the main lens at one end of the barrel, and then enters the human eye through the eyepiece at the other end of the barrel. This kind of telescope is called a refracting telescope, which has a simple structure and is easy to manufacture.
As the aperture of the telescope increases, the shortcomings of the refracting telescope also appear: under the action of gravity or temperature changes, the center of the lens will be deformed, which will affect the imaging quality. Light rays of different colors will be dispersed after passing through the lens, making it difficult to accurately focus on one point, resulting in chromatic aberration in the observed image. When the light passes through the lens, the signal in the ultraviolet band will be seriously absorbed, making it impossible to accurately observe the lens.
Therefore, at the end of the 19th century, no attempt was made to enlarge the aperture of refractor telescopes. In 1897, the Yerkes Observatory in the United States built the 1.02-meter refractor telescope, which is still the largest in the refractor telescope family.
In 1666, Newton, the pioneer of physics, discovered through the phenomenon of dispersion that the white light we see every day is actually composed of light of different wavelengths and colors. Newton immediately realized that the refracting telescope must have chromatic aberration, and proved his idea through experiments.
To overcome this problem, Newton designed an entirely new telescope: it placed a spherical lens at the bottom of the tube that reflected light. Light entering the lens barrel is reflected by the spherical mirror and then focused on a point in front of the lens barrel. Newton directed the light to one side of the barrel through another flat mirror,for viewers to watch. Telescopes using this principle are called reflective telescopes, which effectively solve the dispersion problem of refracting telescopes.
Afterwards, astronomers improved the lens shape and optical path structure on the basis of reflective telescopes, and developed reflective telescope systems such as the Segling system, R-C system, and folded axis system, further improving the reflective telescope. performance. Users can choose according to different observation needs. The mechanical structure of the telescope can well support the reflective telescope lens, which solves the problem of lens deformation to a certain extent.
Of course, the telescopes mentioned in this article are all optical telescopes, and they are also the most widely used and familiar telescopes. For other astronomical telescopes, we will introduce them later.