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Plate scale is usually expressed in arcseconds per mm: , where f is in mm, [1] or expressed in arcseconds per pixel after further division through the pixel scale. Plate scale is not changed when telescopes zoom in or out because the same amount of sky will be in the pixel whether it is enlarged or shrunk.
The result, θ = 4.56/D, with D in inches and θ in arcseconds, is slightly narrower than calculated with the Rayleigh criterion. A calculation using Airy discs as point spread function shows that at Dawes' limit there is a 5% dip between the two maxima, whereas at Rayleigh's criterion there is a 26.3% dip. [ 3 ]
In computer graphics, per-pixel lighting refers to any technique for lighting an image or scene that calculates illumination for each pixel on a rendered image. This is in contrast to other popular methods of lighting such as vertex lighting, which calculates illumination at each vertex of a 3D model and then interpolates the resulting values over the model's faces to calculate the final per ...
Instead, for a source with a total or integrated magnitude m extending over a visual area of A square arcseconds, the surface brightness S is given by = + . For astronomical objects, surface brightness is analogous to photometric luminance and is therefore constant with distance: as an object becomes fainter with distance, it also becomes ...
A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol ′, is a unit of angular measurement equal to 1 / 60 of one degree. [1] Since one degree is 1 / 360 of a turn, or complete rotation, one arcminute is 1 / 21 600 of a turn.
Pixels can be used as a unit of measure such as: 2400 pixels per inch, 640 pixels per line, or spaced 10 pixels apart. Pixel art The measures " dots per inch " (dpi) and " pixels per inch " (ppi) are sometimes used interchangeably, but have distinct meanings, especially for printer devices, where dpi is a measure of the printer's density of dot ...
Popular exposure chart type, showing exposure values EV (red lines) as combinations of aperture and shutter speed values. The green lines are sample program lines, by which a digital camera automatically selects both the shutter speed and the aperture for given exposure value (brightness of light), when set to Program mode (P) .
Other factors include pixel noise, pixel cross-talk, substrate penetration, and fill factor. A common problem among non-technicians is the use of the number of pixels on the detector to describe the resolution. If all sensors were the same size, this would be acceptable. Since they are not, the use of the number of pixels can be misleading.