It is the procedure by which permanent images are obtained on sensitized surfaces by means of the photochemical action of light or other forms of radiant energy.
Science, which studies from outer space to the world of subatomic particles, relies heavily on photography. In the nineteenth century it was the exclusive domain of a few professionals, as large cameras and glass photographic plates were required. However, during the first decades of the twentieth century, with the introduction of the film and the portable camera, it was made available to the general public.
But in no field of science has photography played a role as important as in astronomy. By placing a photographic plate in the focal plane of a telescope, astronomers can obtain accurate images of the situation and brightness of celestial bodies. Comparing photographs of the same area of the sky, taken at different times, the movements of certain celestial bodies, such as comets, can be detected.
An important quality of the photographic plate used in astronomy is its ability to capture, through long-term exposures, almost imperceptible astronomical objects that cannot be observed visually.
In recent times the sensitivity of photography has been improved through techniques that allow greater image accuracy. In a process known as photoelectric effect, starlight releases electrons in a photocathode located in the focal plane of the telescope. The released electrons are directed towards a photographic plate to form the image.
Thanks to certain computer techniques, more detailed and accurate images are obtained, sometimes from blurry and remote photographs of outer space. Computers digitize photographic information and then reproduce it with a greater definition.
On this website you can see hundreds of examples of astronomical photographs.
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