Depth of Field
... Depth of Field The distance range between the nearest and farthest objects that appear in acceptably sharp focus. Depth of field depends on the lens opening, the focal length of the lens, and the distance from the lens to the subject. ...
... Depth of Field The distance range between the nearest and farthest objects that appear in acceptably sharp focus. Depth of field depends on the lens opening, the focal length of the lens, and the distance from the lens to the subject. ...
Clusters of galaxies
... Identification, deep photometry and spectroscopy of 10 clusters around z ~ 0.5 and 10 around z ~ 0.8 Spectroscopy is FORS2 (R ~ 1200) Science goals are build up of stellar populations with redshift (plus weak lensing). ...
... Identification, deep photometry and spectroscopy of 10 clusters around z ~ 0.5 and 10 around z ~ 0.8 Spectroscopy is FORS2 (R ~ 1200) Science goals are build up of stellar populations with redshift (plus weak lensing). ...
Lecture-12-Optics
... Most of the incident light undergoes specular reflection, similar to a plane mirror, and this occurs when i = m and m = 0 for the zeroth order beam. The problem is that most of the irradiance is wasted for the purpose of spectroscopy. It is possible to shift the reflected energy distribution into ...
... Most of the incident light undergoes specular reflection, similar to a plane mirror, and this occurs when i = m and m = 0 for the zeroth order beam. The problem is that most of the irradiance is wasted for the purpose of spectroscopy. It is possible to shift the reflected energy distribution into ...
the optical (light) microscope
... Use of a yellow-green filter and orthochromatic film yields optimum results. However, achromats do provide a relatively long working distance, that is, the distance from the front lens of the objective to the specimen surface. Working distance decreases as magnification of the objective increases. ...
... Use of a yellow-green filter and orthochromatic film yields optimum results. However, achromats do provide a relatively long working distance, that is, the distance from the front lens of the objective to the specimen surface. Working distance decreases as magnification of the objective increases. ...
op_bessel1 - School of Physics
... in an opaque screen represents an obstruction. On an observation screen placed after the hole, the pattern of light may show a set of bright and dark fringes around a central bright spot. Fraunhofer diffraction occurs when both the incident and diffracted waves are effectively plane. This occurs whe ...
... in an opaque screen represents an obstruction. On an observation screen placed after the hole, the pattern of light may show a set of bright and dark fringes around a central bright spot. Fraunhofer diffraction occurs when both the incident and diffracted waves are effectively plane. This occurs whe ...
Fraunhofer Diffraction from a circular aperture
... in an opaque screen represents an obstruction. On an observation screen placed after the hole, the pattern of light may show a set of bright and dark fringes around a central bright spot. Fraunhofer diffraction occurs when both the incident and diffracted waves are effectively plane. This occurs whe ...
... in an opaque screen represents an obstruction. On an observation screen placed after the hole, the pattern of light may show a set of bright and dark fringes around a central bright spot. Fraunhofer diffraction occurs when both the incident and diffracted waves are effectively plane. This occurs whe ...
Some Issues from Advanced Lithography General
... But that was already pushing the Hg lamp to its limits, and it was soon replaced by so-called DUV (for deep ultraviolet) excimer lasers. Excimer lasers are based on rather strange materials: Compounds of noble gases like KrF, or ArF. Rather unstable stuff, but emitting at 248 nm (KrF) or 193 nm (ArF ...
... But that was already pushing the Hg lamp to its limits, and it was soon replaced by so-called DUV (for deep ultraviolet) excimer lasers. Excimer lasers are based on rather strange materials: Compounds of noble gases like KrF, or ArF. Rather unstable stuff, but emitting at 248 nm (KrF) or 193 nm (ArF ...
Aperture
In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. The aperture determines how collimated the admitted rays are, which is of great importance for the appearance at the image plane. If an aperture is narrow, then highly collimated rays are admitted, resulting in a sharp focus at the image plane. If an aperture is wide, then uncollimated rays are admitted, resulting in a sharp focus only for rays with a certain focal length. This means that a wide aperture results in an image that is sharp for things at the correct distance. The aperture also determines how many of the incoming rays are actually admitted and thus how much light reaches the image plane (the narrower the aperture, the darker the image for a given exposure time). In the human eye, the pupil is the aperture.An optical system typically has many openings, or structures that limit the ray bundles (ray bundles are also known as pencils of light). These structures may be the edge of a lens or mirror, or a ring or other fixture that holds an optical element in place, or may be a special element such as a diaphragm placed in the optical path to limit the light admitted by the system. In general, these structures are called stops, and the aperture stop is the stop that determines the ray cone angle, or equivalently the brightness, at an image point.In some contexts, especially in photography and astronomy, aperture refers to the diameter of the aperture stop rather than the physical stop or the opening itself. For example, in a telescope the aperture stop is typically the edges of the objective lens or mirror (or of the mount that holds it). One then speaks of a telescope as having, for example, a 100 centimeter aperture. Note that the aperture stop is not necessarily the smallest stop in the system. Magnification and demagnification by lenses and other elements can cause a relatively large stop to be the aperture stop for the system.Sometimes stops and diaphragms are called apertures, even when they are not the aperture stop of the system.The word aperture is also used in other contexts to indicate a system which blocks off light outside a certain region. In astronomy for example, a photometric aperture around a star usually corresponds to a circular window around the image of a star within which the light intensity is assumed.