A photographic plate exposed on a clear night reproduces the appearance of the portion of the sky concerned, with more or fewer stars according to the power of the telescope that is being used.
Just as a photographic plate receives a different impression of a cluster of stars when a telescope is part of the intervening medium, so a brain receives a different impression when an eye and an optic nerve are part of the intervening medium.
This aims sound waves at your body which bounce back and give an echo picture on a photographic plate
. They developed out of military sonar used to detect submarines in the Second World War.
The evidence of the century-old discovery was unearthed about a year ago, when Jay Farihi from the University College London contacted Carnegie Observatories Director John Mulchaey regarding a photographic plate
in the latter's archive that contained a stellar spectrum of van Maanen's star.
To examine this, he wrapped a photographic plate
in black paper and placed different phosphorescent salts on it.
Conventional photographic photometry depended on measuring the diameters of star images but Fabry photometry involved spreading out the starlight evenly by means of a lens placed close to the image and focusing the objective of the telescope onto the photographic plate
. The density of the image on the photographic plate
was afterwards measured with a microdensitometer.
On November 8, 1895 Professor Wilhem Roentgen discovered X-rays when only the bones of his hand showed through when he put it over a photographic plate
Local photographers continued to preserve events in the town on photographic plate
and film right through the 19th and 20th centuries.
Many of his images show a characteristic lens aberration, since he was unable to focus the entire image across the width of the photographic plate
. As might be expected, Kerr has chosen to focus the centre of his image and leave the periphery out of focus.
The technique was developed in the late 1870s by Francis Galton, the founder of eugenics, who superimposed multiple portraits of individuals representing what he deemed a "natural kind" (the criminal, for instance) onto a single photographic plate
in order to reveal what the "ideal" of that type would look like.
. The instrument was useful for analyzing nonferrous materials, but the 20-cm focal length produced an unresolved continuum with specimens containing heavy metals such as iron.
Most of the alpha particles passed through, unaffected and undeflected, recording themselves on the photographic plate