24 relations: Achromatic lens, Aspheric lens, Cartesian oval, Curved mirror, Distortion (optics), F-number, Focus (optics), Hubble Space Telescope, Lens (optics), List of refractive indices, Maksutov telescope, Mirror, Optical aberration, Optical axis, Optics, Parabolic reflector, Reflection (physics), Refraction, Ritchey–Chrétien telescope, Schmidt corrector plate, Soft focus, Sphere, Star, Telescope.
An achromatic lens or achromat is a lens that is designed to limit the effects of chromatic and spherical aberration.
An aspheric lens or asphere is a lens whose surface profiles are not portions of a sphere or cylinder.
In geometry, a Cartesian oval, named after René Descartes, is a plane curve, the set of points that have the same linear combination of distances from two fixed points.
Christmas is an annual festival commemorating the birth of Jesus Christ,Martindale, Cyril Charles.
The Christmas season, also called the festive season, or the holiday season (mainly in the U.S. and Canada; often simply called the holidays),, is an annually recurring period recognized in many Western and Western-influenced countries that is generally considered to run from late November to early January.
Christmas Eve is the evening or entire day before Christmas Day, the festival commemorating the birth of Jesus.
Christmas traditions vary from country to country.
A curved mirror is a mirror with a curved reflecting surface.
In geometric optics, distortion is a deviation from rectilinear projection; a projection in which straight lines in a scene remain straight in an image.
The f-number of an optical system (such as a camera lens) is the ratio of the system's focal length to the diameter of the entrance pupil.
In geometrical optics, a focus, also called an image point, is the point where light rays originating from a point on the object converge.
The Hubble Space Telescope (HST) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation.
A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction.
Many materials have a well-characterized refractive index, but these indexes depend strongly upon the frequency of light.
The Maksutov (also called a "Mak") is a catadioptric telescope design that combines a spherical mirror with a weakly negative meniscus lens in a design that takes advantage of all the surfaces being nearly "spherically symmetrical".
A mirror is an object that reflects light in such a way that, for incident light in some range of wavelengths, the reflected light preserves many or most of the detailed physical characteristics of the original light, called specular reflection.
New Year is the time or day at which a new calendar year begins and the calendar's year count increments by one.
New Year's Day, also called simply New Year's or New Year, is observed on January 1, the first day of the year on the modern Gregorian calendar as well as the Julian calendar.
In the Gregorian calendar, New Year's Eve (also known as Old Year's Day or Saint Sylvester's Day in many countries), the last day of the year, is on 31 December which is the seventh day of Christmastide.
Aberration in optics refers to a defect in a lens such that light is not focused to a point, but is spread out over some region of space, and hence an image formed by a lens with aberration is blurred or distorted, with the nature of the distortion depending on the type of aberration.
An optical axis is a line along which there is some degree of rotational symmetry in an optical system such as a camera lens or microscope.
Optics is the branch of physics which involves the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it.
A parabolic (or paraboloid or paraboloidal) reflector (or dish or mirror) is a reflective surface used to collect or project energy such as light, sound, or radio waves.
Reflection is the change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated.
Refraction is the change in direction of wave propagation due to a change in its transmission medium.
A Ritchey–Chrétien telescope (RCT or simply RC) is a specialized variant of the Cassegrain telescope that has a hyperbolic primary mirror and a hyperbolic secondary mirror designed to eliminate off-axis optical errors (coma).
A Schmidt corrector plate is an aspheric lens which is designed to correct the spherical aberration in the spherical primary mirror it is combined with.
In photography, soft focus is a lens flaw, in which the lens forms images that are blurred due to spherical aberration.
A sphere (from Greek σφαῖρα — sphaira, "globe, ball") is a perfectly round geometrical object in three-dimensional space that is the surface of a completely round ball (viz., analogous to the circular objects in two dimensions, where a "circle" circumscribes its "disk").
A star is type of astronomical object consisting of a luminous spheroid of plasma held together by its own gravity.
A telescope is an optical instrument that aids in the observation of remote objects by collecting electromagnetic radiation (such as visible light).
2018 has been designated as the third International Year of the Reef by the International Coral Reef Initiative.
2019 (MMXIX) will be a common year starting on Tuesday of the Gregorian calendar, the 2019th year of the Common Era (CE) and Anno Domini (AD) designations, the 19th year of the 3rd millennium, the 19th year of the 21st century, and the 10th and last year of the 2010s decade.