|
TellStar
TellStar was the first graphical astronomy program available for personal computers. It was sold from 1980 to 1986 by Scharf Software Services, initially for the Apple II, and later for IBM PC compatibles. The program came in two versions: Level 1, which only plotted the Northern Hemisphere; and Level 2, which could plot the entire celestial sphere. TellStar could predict the position of celestial objects at any point on Earth and at any time between 0 and 3000AD. The program's database included various celestial objects such as planets, Messier objects, and stars from three different catalogs, totaling over 600 entries. Plots could be generated in nine directions: N, NE, E, SE, S, SW, W, NW and overhead (a view of the sky upwards). By clicking on a star with a joystick or gamepad, users could access detailed information about each object, including its declination, right ascension, magnitude, rising and setting times in sidereal time and Universal Time Universal Time (UT o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telstar
Telstar is the name of various communications satellites. The first two Telstar satellites were experimental and nearly identical. Telstar 1 launched on top of a Thor-Delta rocket on July 10, 1962. It successfully relayed through space the first television pictures, telephone calls, and telegraph images, and provided the first live transatlantic television feed. Telstar 2 launched May 7, 1963. Telstar 1 and 2—though no longer functional—still orbit the Earth. Description Belonging to AT&T, the original Telstar was part of a multi-national agreement among AT&T (USA), Bell Telephone Laboratories (USA), NASA (USA), GPO (United Kingdom) and the National PTT (France) to develop experimental satellite communications over the Atlantic Ocean. Bell Labs held a contract with NASA, paying the agency for each launch, independent of success. Six ground stations were built to communicate with Telstar, one each in the US, France, the UK, Canada, West Germany and Italy. The Am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamepad
A gamepad is a type of video game controller held in two hands, where the fingers (especially thumbs) are used to provide input. They are typically the main input device for video game consoles. Features Gamepads generally feature a set of buttons handled with the right thumb and a direction controller handled with the left. The direction controller has traditionally been a four-way digital cross (also named a joypad, or alternatively a D-pad, and never called arrow keys), but most modern controllers additionally (or as a substitute) feature one or more analog sticks. Some common additions to the standard pad include shoulder buttons (also called "bumpers") and triggers placed along the edges of the pad (shoulder buttons are usually digital, i.e. merely on/off; while triggers are usually analog); centrally placed ''start'', ''select'', and ''home'' buttons, and an internal motor to provide force feedback. Analog triggers, like that of the GameCube controller, are pres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Universal Time
Universal Time (UT or UT1) is a time standard based on Earth's rotation. While originally it was mean solar time at 0° longitude, precise measurements of the Sun are difficult. Therefore, UT1 is computed from a measure of the Earth's angle with respect to the International Celestial Reference Frame (ICRF), called the Earth Rotation Angle (ERA, which serves as a modern replacement for Greenwich Mean Sidereal Time). UT1 is the same everywhere on Earth. UT1 is required to follow the relationship :ERA = 2π(0.7790572732640 + 1.00273781191135448'' · Tu'') radians where ''Tu'' = (Julian UT1 date - 2451545.0). History Prior to the introduction of standard time, each municipality throughout the clock-using world set its official clock, if it had one, according to the local position of the Sun (see solar time). This served adequately until the introduction of rail travel in Britain, which made it possible to travel fast enough over long distances to require continu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sidereal Time
Sidereal time (as a unit also sidereal day or sidereal rotation period) (sidereal ) is a timekeeping system that astronomers use to locate celestial objects. Using sidereal time, it is possible to easily point a telescope to the proper coordinates in the night sky. In short, sidereal time is a "time scale that is based on Earth's rate of rotation measured relative to the fixed stars", or more correctly, relative to the March equinox. Viewed from the same location, a star seen at one position in the sky will be seen at the same position on another night at the same sidereal time. This is similar to how the time kept by a sundial (Solar time) can be used to find the location of the Sun. Just as the Sun and Moon appear to rise in the east and set in the west due to the rotation of Earth, so do the stars. Both Solar time and sidereal time make use of the regularity of Earth's rotation about its polar axis: solar time following the Sun while, roughly speaking, sidereal time fol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heliacal Rising
The heliacal rising ( ) or star rise of a star occurs annually, or the similar phenomenon of a planet, when it first becomes visible above the eastern horizon at dawn just before sunrise (thus becoming "the morning star") after a complete orbit of the earth around the sun. Historically, the most important such rising is that of Sirius, which was an important feature of the Egyptian calendar and astronomical development. The rising of the Pleiades heralded the start of the Ancient Greek sailing season, using celestial navigation. Cause and significance Relative to the stars, the sun appears to drift eastward about one degree per day along a path called the ecliptic because there are 360 degrees in any complete revolution (circle), which takes about 365 days in the case of one revolution of the earth around the sun. Any given "distant" star in the belt of the ecliptic will be visible at night for only half of the year, when it will always remain below the horizon. During th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apparent Magnitude
Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's light caused by interstellar dust along the line of sight to the observer. The word ''magnitude'' in astronomy, unless stated otherwise, usually refers to a celestial object's apparent magnitude. The magnitude scale dates back to the ancient Roman astronomer Claudius Ptolemy, whose star catalog listed stars from 1st magnitude (brightest) to 6th magnitude (dimmest). The modern scale was mathematically defined in a way to closely match this historical system. The scale is reverse logarithmic: the brighter an object is, the lower its magnitude number. A difference of 1.0 in magnitude corresponds to a brightness ratio of \sqrt /math>, or about 2.512. For example, a star of magnitude 2.0 is 2.512 times as bright as a star of magnitude 3.0 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Right Ascension
Right ascension (abbreviated RA; symbol ) is the angular distance of a particular point measured eastward along the celestial equator from the Sun at the March equinox to the ( hour circle of the) point in question above the earth. When paired with declination, these astronomical coordinates specify the location of a point on the celestial sphere in the equatorial coordinate system. An old term, ''right ascension'' ( la, ascensio recta), "''Ascensio recta'' Solis, stellæ, aut alterius cujusdam signi, est gradus æquatorus cum quo simul exoritur in sphæra recta"; roughly translated, "''Right ascension'' of the Sun, stars, or any other sign, is the degree of the equator that rises together in a right sphere" refers to the ''ascension'', or the point on the celestial equator that rises with any celestial object as seen from Earth's equator, where the celestial equator intersects the horizon at a right angle. It contrasts with ''oblique ascension'', the point on the ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Declination
In astronomy, declination (abbreviated dec; symbol ''δ'') is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle. Declination's angle is measured north or south of the celestial equator, along the hour circle passing through the point in question. The root of the word ''declination'' (Latin, ''declinatio'') means "a bending away" or "a bending down". It comes from the same root as the words ''incline'' ("bend foward") and ''recline'' ("bend backward"). In some 18th and 19th century astronomical texts, declination is given as ''North Pole Distance'' (N.P.D.), which is equivalent to 90 – (declination). For instance an object marked as declination −5 would have an N.P.D. of 95, and a declination of −90 (the south celestial pole) would have an N.P.D. of 180. Explanation Declination in astronomy is comparable to geographic latitude, projected onto the celestial sphere, and right ascension is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joystick
A joystick, sometimes called a flight stick, is an input device consisting of a stick that pivots on a base and reports its angle or direction to the device it is controlling. A joystick, also known as the control column, is the principal control device in the cockpit of many civilian and military aircraft, either as a centre stick or side-stick. It often has supplementary switches to control various aspects of the aircraft's flight. Joysticks are often used to control video games, and usually have one or more push-buttons whose state can also be read by the computer. A popular variation of the joystick used on modern video game consoles is the analog stick. Joysticks are also used for controlling machines such as cranes, trucks, underwater unmanned vehicles, wheelchairs, surveillance cameras, and zero turning radius lawn mowers. Miniature finger-operated joysticks have been adopted as input devices for smaller electronic equipment such as mobile phones. Aviation Joy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apple II
The Apple II (stylized as ) is an 8-bit home computer and one of the world's first highly successful mass-produced microcomputer products. It was designed primarily by Steve Wozniak; Jerry Manock developed the design of Apple II's foam-molded plastic case, Rod Holt developed the switching power supply, while Steve Jobs's role in the design of the computer was limited to overseeing Jerry Manock's work on the plastic case. It was introduced by Jobs and Wozniak at the 1977 West Coast Computer Faire, and marks Apple's first launch of a personal computer aimed at a consumer market—branded toward American households rather than businessmen or computer hobbyists. ''Byte'' magazine referred to the Apple II, Commodore PET 2001, and TRS-80 as the "1977 Trinity". As the Apple II had the defining feature of being able to display color graphics, the Apple logo was redesigned to have a spectrum of colors. The Apple II is the first model in the Apple II series, followed by App ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KPJK
KPJK (channel 60) is a non-commercial independent television station licensed to San Mateo, California, United States, serving the San Francisco Bay Area. Owned by Northern California Public Media (not to be confused with Northern California Public Broadcasting), it is sister to PBS member station KRCB (channel 22) and NPR member stations KRCB-FM (104.9) and KRCG-FM (91.1). KPJK's studios are located on West Hillsdale Boulevard on the campus of the College of San Mateo in southwestern San Mateo, and its transmitter is located atop Sutro Tower in San Francisco. KPJK operates 24 hours a day with programming coming from American Public Television and other independent producers. Previously, the station was owned by the College of San Mateo, and operated as KCSM-TV. History The KCSM stations were originally established by the College of San Mateo as college radio and student television station training facilities for radio and television broadcasters. Many well-known media pers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Messier Object
The Messier objects are a set of 110 astronomical objects catalogued by the French astronomer Charles Messier in his ''Catalogue des Nébuleuses et des Amas d'Étoiles'' (''Catalogue of Nebulae and Star Clusters''). Because Messier was only interested in finding comets, he created a list of those non-comet objects that frustrated his hunt for them. The compilation of this list, in collaboration with his assistant Pierre Méchain, is known as ''the Messier catalogue''. This catalogue of objects is one of the most famous lists of astronomical objects, and many Messier objects are still referenced by their Messier numbers. The catalogue includes most of the astronomical deep-sky objects that can easily be observed from Earth's Northern Hemisphere; many Messier objects are popular targets for amateur astronomers. A preliminary version first appeared in 1774 in the ''Memoirs'' of the French Academy of Sciences for the year 1771. The first version of Messier's catalogue con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
